accounts of our memories are like meticulously made reports in laboratory notebooks of carefully observed results obtained by using poorly calibrated apparatus designed for a different type of experiment. They may faithfully reproduce information, but that information is not entirely reliable.
Is remembering something a sufficent reason to believe it happended?
I came to the realisation that something I had remembered, was not actually something that had happened. I had experienced it as a genuine memory – but on reflection soon afterwards I knew full well it was not the case (indeed, could not have been the case). This could have been rather disconcerting in other circumstances. That is, if this had occurred during what we consider a normal state of consciousness. Even so, it gave me pause for thought.
Memories and false beliefs about memory
Memory is one of these things we all know about, but tends to be generally poorly understood. Nomenclature such as 'remember', 'recall', and 'forget', are part of the mental register – the set of terms that are used in everyday discourse to talk about mental experience and related phenomena (Taber, 2013). Our familiarity with this kind of talk probably encourages most of us to feel we have a pretty good handle on the basis of what memory is; what remembering is; and what it means to forget.
Yet, actually, this is not generally so. Research shows that even when people recall events with clarity and are confident in the accuracy of these recollections, their memories may not be trustworthy. Certainly much of what we remember is basically sound (though I am not sure anyone has a good estimate of just how much!) But details often get changed. And sometimes, more than just details.
We represent experience in memory but this is not usually akin to making a video record (even if some people experience their memories as if watching a recording). Memory (the faculty) seems to have evolved to give us an abstracted, generalised impression of past experience. From an evolutionary perspective, we have inherited the kind of memory that was selected for in the context of how our ancestors lived.
Related experiences are often represented without proper discrimination. So, if you regularly get the train to work, you have a memory of this – but not discrete memories of each separate occasion. At least, not unless you are one of those rare people who have been gifted, or perhaps cursed (Luria, 1987), with an eidetic memory. Arguably, for most purposes, a generalised memory of a much repeated scenario is more useful than a large set of records of similar events distinguished by variations in incidental detail. There is value in remembering how to make a cup of tea or unlock a door: less so in having a record of each time one has made tea or unlocked doors.
Memory as a reconstruction
Research shows that memories are often in part constructed – representations ('in memory') activated in remembering offer a partial account, which is filled-in with feasible details BEFORE the memory is presented to consciousness. The person reporting the memory does not know which elements were actually recalled, and which then added.
This has been shown, for example, by testing people a few days after they have been told an unfamiliar story. Typically, people get some points correct, forget some details, but also change details, or even add material that was never in the original. But the person 'remembering' (actually, reconstructing) the story does not necessarily have any less confidence in the fabricated elements, as they have been integrated into the account pre-consciously: 'out of mind' so to speak. Reports of memories are usually honest – it is just that they are honest reports of imperfect memories. Eye witness testimony is famously unreliable, but not because most people lie.
In this way, accounts of our memories are like meticulously made reports in laboratory notebooks of carefully observed results obtained by using poorly calibrated apparatus designed for a different type of experiment. They may faithfully reproduce information, but that information is not entirely reliable. We cannot trust such results just because someone provides an honest report of what was noted down in the record.
Memories are somewhat like those historical reconstructions based on incomplete accounts filled in by a dramatist to offer a full narrative for the viewer, perhaps with some scenes moved to locations that seem to be more keeping with the overall progression of the storyline (or are just considered more visually compelling). Crick and Watson may not have had those specific conversations as portrayed when walking across the backs, or in The Eagle, but there is a sense in which the story has greater coherence and truth if shown that way. Not a strict, historical, truth, of course – but perhaps it creates a better mythology, or acts as more effective pedagogy, or just offers a better aesthetic?
"Look, according to the script here, they are going to film us having this conversation on the tennis court." (Tim Pigott-Smith as Francis Crick and Jeff Goldblum as Jim Watson in a still from the 1987 Horizon special docudrama, 'Life Story' {a.k.a. 'The Race for the Double Helix'}.)
Memories are not fixed. Each time you activate a memory you change the trace. It is therefore possible to 'plant' memories. The first time you are asked to recall the crime scene you are asked if you saw a knife and report not. But when asked again at a later date, you may now associate a knife with the scene (as you had been invited to think about it in that context previously, the image has got linked to the memory). This can be done deliberately, but criminal investigators have to be very careful of accidentally planting memories.
People sometimes recall events from very early in their lives at an age research suggests is before distinct autobiographical memories can be laid down. Presumably, what is actually being remembered is having previously imagined the scene years before when told about it.
I can picture myself in my pram telling enquiring passers-by my name and address – but that is actually my memory of a report of someone else's memory. I almost believe I recall escaping from my playpen by emptying out the toy box and turning it upside down to act as step. But that could be a fabrication I have been fed. I do know these are memories ofstories about me and not actual memories of the events, but perhaps some of my actual early memories of events were also 'planted' without my being aware of this?
It is all in the mind
After all, what we actually recall is a representation ofour experience, which is effectively mental. We have mental experiences when we are out acting on the environment (e.g., walking in the woods) – but also when watching a film, or listening to a story, or simply daydreaming. And, indeed, we also have mental experiences when we sleep.
Researchers have found children giving convincing and committed accounts of how when they were younger
they had to attend hospital for a minor emergency, or
when they drifted away from caregivers at the shops and got lost
although these were imaginary events which the researchers themselves had previously planted, and which parents confirmed did not reflect any actual event the child had experienced. (Such research raises ethical issues – now we know memories can be suggested by researchers, is it ethical for investigators to continue to carry out such studies? If so, what are the limits on the kinds of memories it is acceptable to try and plant?)
False memory syndrome
A very serious consequence of this phenomenon has been the recognition that accusations against parents and teachers and other caregivers of child abuse can arise from the inadvertent planting of false memories when children are questioned. Careful probing of the children's memories may be needed over sequences of interviews. Unfortunately, that very scenario also provides suitable conditions for leading questions to plant false memories.
Identifying cases of child abuse can be especially challenging as young children may not understand what has happened to them (especially in cases of sexual assaults) and/or may be traumatised. Young children are also less able to distinguish memories of real and imaginary events.
Recalling previous mental states
There is a procedure undertaken in psychology where a youngster is shown a biscuit box, say, and asked to guess its contents. For example:
Cookies.
The child is then shown that the box actually contains something incongruous:
Pebbles!
They are then asked what they had thought was in the box when first shown it, before they saw inside:
Pebbles, of course.
This is normal behaviour. The child gives what for them is a genuine response – but it is false. It is not a lie – it would hardly be convincing if it was. With maturation a child becomes able to distinguish what I think now from what I thought before – but below a certain age this distinction is simply not available.
That particular result is specific to young children, but a degree of memory distortion is normal for the rest of us – indeed the best of us, according to the historian/philosopher of science Thomas Kuhn,
"Not always, but quite usually, scientists will strenuously resist recognising that their discoveries were the product of beliefs and theories incompatible with those to which the discoveries themselves gave rise."
Kuhn was not suggesting that scientists were seeking to claim a prescience they did not have, but simply that they too are effected by the difficulty of returning to an earlier state of ignorance before they slowly built a more nuanced and deeper understanding of a field. The instrument they used to expand their understanding – their prior understanding – was the very thing that was being modified. That is something teachers need to bear in mind – many of those things that now seem obvious and straightforward to the expert were obscure and complex when met as a novice.
The dilemma of 'recovered' memories of abuse
It is obviously imperative to detect and stop sexual abuse, but it became clear that in some communities there seemed to be an inordinate amount of such child abuse going on, often involving strange rituals more at home in a Hammer Horror film. Children who were perfectly happy at home were being separated from their families on the basis of an investigative methodology which unfortunately created the 'evidence' of abuse (and made it indistinguishable from any real memories of actual abuse).
Some adults in therapy also found they gradually uncovered (or perhaps, actually, gradually constructed) previously undetected memories of childhood abuse, and consequently became estranged from parents that they now labelled abusers. Of course, such 'recovered' memories could be real, but sometimes they were not, and unfortunately recall does not come with metadata tags to tell us how and when what is being recalled was first represented in memory.
How is it possible that adults might live for decades without any conscious awareness that their parents had abused them as children, only for this to come to light when they entered into a psychoanalytic relationship with a therapist? Supposedly, the memories of something so awful, and often inconsistent with an otherwise happy family life, had been repressed.
There are different views on whether false memory syndrome leading to fabricated accusations of abuse is very widespread as has sometimes been claimed (an 'epidemic'), or is just an occasional aberration (Goodman, Gonzalves & Wolpe, 2019; Otgaar, Howe & Patihis, 2022). The challenge is that when there is nothing to corroborate memory with, then all we have is the memory; and memory is fallible and susceptible to distortion.
Memories are like conceptions
The research into student conceptions in science makes it clear that a learners' knowledge of a topic does not exist on a single dimension from ignorance to knowledge – they can have knowledge that is more or less complete, but also alternative conceptions that are more or less canonical. In a similar way, memories can also be more or less complete, but also more or less accurate – indeed, more or less fabricated.
Memory and sleep
We know that sleep is essential to good health and, indeed, that healthy sleep must include dreaming. It is normal to dream every night, although we may only remember dreams if they occur just before waking. Clearly, sleep must be physiologically important as sleeping involves taking the significant risk of losing awareness of our environment when, for example, predators may be around.
Sleeping leaves us vulnerable. Of course, some creatures are less vulnerable than others when they nod off. (Image by PublicDomainPictures from Pixabay)
One of the areas that sleep is considered to support is memory consolidation. That is, without good sleep, our ability to update and maintain our memories suffers. I do not think the details of this are well understood – but the effects of sleep deprivation are well known (such that it can be used as a form of torture).
No one really knows for sure the function of dreams, or whether, perhaps, dreams are just an epiphenomenon, a kind of by-product of the maintenance processes going on in the brain during sleep. There is a very long tradition of trying to read meaning in (or into!) dreams (the story of Daniel in the Bible Old Testament for example) and the interpretation of dreams was a key part of Sigmund Freud's psychoanalysis. Dreams are such a part of our lives, it often seems they must have significance – but there is no strong scientific support to suggest this is so. Given the nature of most of my dreams, I find this reassuring.
Autobiographical and semantic memory
Our memories represent both autobiographical and semantic material. That is, we recall specific events in our lives as well as abstract material such as Ohm's law, the theory of natural selection, or the molecular structure of benzene.
So, if our sleeping brains are maintaining memory function and this involves activating memory traces, and we experience – or make sense of – some of this as dreaming, then why do my dreams involve me in 'social' situations, but I do not (that I can recall) dream about, say, molecular shapes or circuit configurations? After all, August Kekulé supposedly discovered the structure of benzene when he was drifting into sleep.
Does this reflect my lack of genius – would an Albert Einstein or a Richard Feynman dream in abstract mathematical symbols? I do not, at least, not that I notice. Generally my dreams are very mundane, which is why one of last night's dream's seemed out of place.
A dream party (no teaching involved)
I was at a kind of Hollywood-type party – a party attended by many of those who would be labelled by the general public as 'stars'. To be fair, I did not recognise (or perhaps, better, actually notice) who most of the people there were: rather I just had the impression that these were 'stars'.
I should point out that I do not tend to go to those kinds of parties (obviously, I do not tend to be invited to them), and indeed I am not really one for parties. So, I am not sure why I was dreaming about being at one.
More typically, my dreams involve teaching situations. Yet, I never actually teach anything substantial in these dreams – more often I am
getting myself ready to teach a class,
organising a class to get ready to work, or
on my way to teach a class (which for various reasons never gets started)
as if my dreaming brain has access to autobiographical material, but does not know any chemistry or physics or research methodology or anything I might actually teach. It seems as if I do not have access to my semantic knowledge for use in my dreams. This raises an interesting question.
If dreaming is considered to support the processes of memory consolidation – why do we not dream about the material we are learning?
(And although I am not taking any formal classes – I read books and listen to podcasts which would provide plenty of subject matter.)
Is it just that this processing happens at a more abstract level that we cannot picture directly in dreams?
Why are dreams not more realistic?
What has long intrigued me about dreams is that although I do sometimes dream about my late wife or close family: in general the people in my dreams seem to be made up, like characters in a fiction. I do not dream about students or classes I have taught but rather populate my dreams with fictional people. This seems odd, as when I am awake I can remember many students I have taught and it would seem more economical for my brain to use their images than construct people de novo. 1 Why are my dreams so 'CGI-heavy' (as in 'computer generated imagery') when it is known that requires a lot of processing?
And this is not just people. In my dreams I am in buildings or in streets, etcetera – but when I awake and can recall a dream I realise that the house I was living in, in the dream, is not my house, or any other house I have ever lived in. Or know. (And when there is an exception, the house seems to have been moved! 3)
The classroom in a dream is not one where I taught, even though there are several very familiar classrooms where I taught a great number of lessons over a period of years. The same applies with the teaching institutions more generally – when I move around these buildings in my dreams I use hallways, go to canteens, and the like; pass thought entrance areas. All these things are experienced as familiar to me – in my dreams, the people, rooms and buildings and sometimes even streets and town centres all seem familiar – but only till I wake up. Then it is immediately clear they were constructed – in effect imagined – and not recalled from real life. Perhaps they are sometimes recalled from a previous dream, but not recalled from my actual 'awake' life. They are familiar in sleep – but not known from my waking life.
[There is a theory that we live to dream. Our real lives, the lives that really matter, are the lives we have in sleep when we dream. In order to maintain these meaningful lives we need the support period when we are awake and eat and, so forth. From this perspective, the question of why we dream disappears. Instead we might ask why we need to be conscious when awake: presumably this makes it easier to find sustenance, mates, shelter and the other things that allows us to continue the human lineage, and to regularly settle down for a good night's sleep.]
There are exceptions. Once when younger and at my parents house, I dreamt that I flew out of their house down the road, turning into the adjoining road then right at a junction into another road that led to the local shops, over the roundabout and headed down to town. I will not bore you with the details except to say the flight was exhilarating rather than scary…and was (certainly, subjectively seemed) detailed. I saw the roads and buildings in detail, and, as far as I could tell when I awoke, accurately. This seemed to me more memory than imagination…with one obvious caveat. In the dream I was seeing everything from maybe 10 metres above the ground looking down. I had walked along those roads hundreds of times, but only from a vantage point of less than two metres above ground level.
Maybe there is a good reason we do not dream realistically too often. When I have had dreams where I interact with real people then I have sometimes become confused later. I have had to realise that 'no, that was just a dream'. If one does not realise on waking, perhaps one would never know of the mistake – but that could have consequences. ("You told me to give the house to Marxist anarchists!")
And awaking from a conversation with a loved one, only to then realise that must have been a dream because the person is no longer with us, is difficult: waking up and realising that was not a real experience, and it could not have been, tends to ratchet the grief process back up a few notches. Spending time with the loved one, only to wake and realise – again – she is gone offers a bitter-sweet counterpoint and reprise to the old adage that it is better to have loved and lost…
All the same, it does suggest that if dreaming is largely a constructive process that requires the brain to design and simulate new but realistic-seeming environments and populate them with convincing androids, then that is an awful lot of mental work. Perhaps it calls upon 'memories' at some level, but it seems largely the work of imagination.
Transitioning to sleep
I had slept for about four hours, but then awoke wishing to use the bathroom. That is not unusual, and more often than not I crawl back into bed and straight back to sleep. On this occasion I just lay there waiting to drop off again. I can often tell when I am about to go to sleep as my visual cortex does its version of the iTunes visualiser and I see various shapes and colours gradually appear and then start moving around. Sometimes, not. But I have a strategy to avoid lying awake worrying that I am not asleep. I go on adventures.
So, I take sea voyages, and spend time relaxing on my private tropical island with its bananas, coconuts and pineapples – I have built quite a repertoire of scenarios I slowly develop knowing that usually the story does not get very far before I drift off somewhere else. (That is, I have represented in memory my previous imagined experiences of my repertoire of getting ready for sleep scenarios.)
However, this time my body did not seem to want to go back to sleep, and I seemed to still be lying awake waiting for sleep hours later. This went on so long I could eventually hear the voices of others in the house, now up to start the day; and eventually they were even leaning over me in bed to try and get access to the breakfast things. (That should have been a clue, even if my sleeping self had forgotten there was no one else in the house.)
Then, I was at the party.
I 'remembered' (…in my dream…) that Elton and I go back a long way (Elton publicity shot accessed from Wikimedia, with apologies to Bernie)
My friend, the superstar
I did not really know the people there – I do not mix in these circles.
But then I saw Sir Elton John, and realised there was someone at the party that I did know well. Elton greeted me, and at that moment I recalled how we regularly engaged in repartee on the morning radio show. In that instant, Elton being there and acknowledging me, fitted with a long-standing and familiar part of my life.
Except, of course, this was completely fabricated. I have never met Sir Elton, and the Elton in my dream was for some reason Elton from the 1980s. And I certainly do not appear on any morning radio show, with or without him. Elton (I am pretty sure) does not know I exist, and would not be seeking me out at the kind of parties that I do not in any case go to, and that I would not be invited to (and that I would not really want to go to even if I was invited. Though meeting Elton would be cool.)
So what? This is just a dream – so, it is not real. I do not usually dream of celebrities. (Though Joe Root tuned up in a dream a while back.2)
Why Elton? I have no idea. I do have a lot of his records and rate him highly as a songwriter/singer/pianist. But my dreams would be pretty crowded if all the musicians who moved me made an appearance. 4 Perhaps I just associate Elton with glitzy parties – and I did not spot Freddie was over the far side of the room.
But that was not the point that really struck me. It was rather a phenomenon that I have noticed before about dreams: that one is in a scenario where something needs explaining (here, Elton greeting me as a friend) and there is an immediate in-fill of backstory which is experienced in the dream as authentic recall. Our brains (i.e., we) are able to make up stuff, and present it to us, and convince us that it is what we have previously experienced: here regular jovial exchanges with Elton on a non-existent radio show. In the waking world (where I am well aware that I do not move in those kinds of circles) I immediately saw through this, but in the context of the dream I simply accepted the false memory as being a genuine, recalled, experience.
So, what is to say something similar is not happening regularly in my waking life?
Almost a century ago, the experimental psychologist Frederic Bartlett (1932/1995) concluded from his empirical studies on memory that the three phenomena we consider separately as perceiving, remembering, and imagining, were not so discrete and separate at all.
Perception, imagination, and memory are generally considered separate mental faculties – but are probably not as distinct as we tend to think
What we think we see or hear is strongly framed by (memory of) previous experiences. What we can imagine is resourced by (memory traces of) what we have experienced – what we have seen and heard in the past. What we think we remember is often fragmentary data filled-out with imaginary components that seem (on the basis of our general experience of the world, i.e., a kind of memory) feasible. What we remember may be based on what we have experienced, or what we have previously imagined we have experienced, or even what has been suggested to us in the past as something we have experienced. The memory that seems so genuine and convincing may be filled-in by guesswork, and may indeed be a memory of something other than a real experience.
Probably, we all live with false memories that we never have reason to question and discard. (Perhaps some of them even do a great deal of good work in supporting our self-esteem and self-worth? Or, perhaps, the opposite?)
Based on past experience, at least as I remember it(!), the Elton dream was atypical, as it involved a real person rather than the usual rolling cast of fictional characters. (But see notes 2 and 4) Perhaps that is just as well, as we are less likely to misconstrue recollections of dreams involving imaginary people in imaginary places as being memories from our waking lives. So, I probably will not meet any stars in my dreams tonight. However, just in case, I wonder if Kate Bush is free?
See you in my dreams?
Work cited:
Bartlett, F. C. (1932/1995) Remembering. A study in experimental and social psychology. Cambridge; Cambridge University Press.
Goodman, G. S., Gonzalves, L., & Wolpe, S. (2019). False memories and true memories of childhood trauma: Balancing the risks. Clinical Psychological Science, 7(1), 29-31.
Kuhn, T. S. (1984/1887) Afterword: Revisiting Planck, in Black-Body Theory and the Quantum Discontinuity, 1894-1912. With a new afterword (pp.349-370). The University of Chicago Press.
Luria, A. R. (1987).The Mind of a Mnemonist: a little book about a vast memory.Harvard University Press.
Otgaar, H., Howe, M. L., & Patihis, L. (2022). What science tells us about false and repressed memories. Memory, 30(1), 16-21.
Schacter, D. L. (Ed.). (1995). Memory Distortion. How minds, brains, and societies reconstruct the past. Harvard University Press.
1 This question vexes me when I also consider that I believe that, in a sense, I do not directly interact any other real people. By that, I mean, that although I seem to be, say, talking to a person in the external world, I only have direct experience of a simulation of them constructed in my brain based on sensory data and past experience. We all (I assume?) have mental conversations with people we know well when they are not present: we think we know what they would say in a situation: how they would react; what they might suggest. When they are [actually, physically] present we are surely engaging the same simulation, just with a modest drip feed of sensory data blending in.
(Does that sound strange? I think it would be more strange that if you have been married for 20 years you would assume that you base your interaction with a spouse primarily on transient and likely incomplete immediate sensory data rather than the detailed mental simulation of them that you have incrementally and iteratively built up over hundred of hours of past experience.)
If I call upon those simulations deliberately when asking myself "what would X think about this?", why not in my dreams? (Perhaps, I suggest above, as realistic dreams that are remembered would too readily be confused with waking experience.)
If my simulation argument seems unconvincing, ask yourself why you feel you are engaging with the same person
when you meet them under different conditions (lighting, background noise);
when you only see a two-dimensional image on a small flat screen; or even
when you only have a low quality reproduction of their voice coming from a tiny speaker?
It is not because the sensory data matches well in these different situations.
2 This is my note of my dream involving cricketer Joe Root
I awoke 3 from a dream where I'd been watching sport – football, and switched to cricket [at this point I seem to be watching television], there was a run out call. English bowler, never seen before, seemed to hesitate as he picked up the ball, but direct hit on wicket – awaiting replays to see if it was a run out.
Joe Root was watching next to me on the grass (this was just after it had been announced he was standing down as test team captain) but seemed fidgety – he was moving about and taking up yoga-like positions. [Note, I am now actually at the cricket match, not watching TV.]
There were two young women, girls really, wearing Summer gear (shorts, top tied up high so bare stomach area). They were exchanging glances, and edging closer to Joe. Eventually he did some kind of flip, and landed on one of the girls who had moved up close behind him.
Giggles.
I joked that this was a litigation issue and he might be sued for millions.
Report of a dream [this is a purely imaginary account and in no way reflects any real (waking!) event involving Joe Root that I am aware of!]
Why Joe Root? Just because he had been mentioned in the news? Perhaps. However Root was involved in two of my own alternative conceptions (we have them in all areas of knowledge, not just science), and in both cases I had sensed there was something I was missing in the particular situation – so, perhaps it might be said I felt some 'cognitive dissonance' until I realised my misunderstandings.
One of these misconceptions concerned advertising for pet insurance* that often featured Root alongside a dog, by a company who sponsored some of the cricket highlights on television. It struck me as odd that this company could afford to air so many adverts employing a leading sportsman when I could not imagine the market for pet insurance was especially lucrative. It eventually dawned on me (many months later) that the company were advertising insurance for people – not pets. Perhaps the dog was meant to represent health (rather than, as I had assumed, a creature likely to soon need veterinary attention). [* Note, my clear memories of regularly seeing advertisements for pet insurance turned out to be unreliable as I had misconstrued the sensory data that became represented in memory.]
The other misconception concerned the regular occurrence of booing of Root on the cricket field. Generally cricket crowds do not boo – although fast bowler Stuart Broad had incurred the wrath of Australian supporters who had taken to booing him. But Root, an English international cricketer, seemed to get booed at English grounds whenever he went out to bat, or when he hit a boundary, even though I was not aware of anything he had done or said likely to offend. And, indeed, from after-match interviews I had seen, I thought he did not seem like a person who would offend a large proportion of spectators. Indeed, he was always polite, and sensible, and modest. Again, it took quite a while before I realised that what I was hearing as "bo:o" was actually the crowd calling out an extended "ro:ot".
3 Actually, this is part of a longer account I noted down because it involved a dream within a dream. The account continues:
I woke up, and went downstairs, and went to the table I use as a desk at the front of the house. Looking out I saw the house opposite [which should have been obscured by my garden hedge] had no door and looked like they were having workers in to put in a new door. Then I realised that the house as a whole (which was much larger than usual, and all red brick [unlike the actual house opposite]) was not finished, and looking around I realised that none of the houses in the street were finished yet. I noticed there was no computer on my desk. I went to look out of the back of the house and saw rolling hills and countryside – it look like the West Country around Bristol. I realised I must still be asleep, and found some paper to write down the dream so I could have a record when I really wake (!). Found a pen but it did not seem to work very well.
So, if I can wake up from one dream within another dream, perhaps I am not actually awake now?
4 I have a note of the guitarist/composer Steve Hackett appearing in one dream that was part of a sequence of scenes I recalled when I awoke,
2. Hackett was in an office with charts/manuscripts for music he intended to play for a concert, and in discussion over whether to bring in a second guitarist to play some parts. A person advising – 'manager'(?) of the venue – was going to play some of the music there in the office.
I am not sure what triggered that, although the previous scene that I recalled was unusual (for me) in that it was an auditory dream5:
listening to the first Genesis album ('From Genesis to Revelation') and noticing atmospheric instrumental passages with subtle electric guitar parts I'd never noticed before
I had not noticed these passages before, because – of course- they are not actually on the album! Steve Hackett did not join Genesis till after that album, but perhaps my sleeping brain was thinking that these were contributions he might have made if he had been in the band then?
5 Again, it seems odd that as much of my waking life is accompanied by music, I seldom dream of music. Indeed the first time I recall this happening I was so struck by the dream that I still recall the occasion over 40 years later. I was about 17 and I had fallen asleep one Sunday afternoon, after a having been up late the night before as someone in the sixth form had had a party. (No, Elton was not there – at least, as far as I recall!) I dreamed what seemed to me at the time a very vivid and detailed rendition of 'Shine on you crazy diamond' by Pink Floyd.
Of course, that is just my recollecti0n of my subjective experience on waking from sleep (that is, the waking memory of the dream) – but the music had (at least) seemed so real and intense and deep that, all these years later, I still remember the effect such a detailed dream had on me when I awoke.
Is it possible that a publisher might be using fictitious academics to attract submissions to its journals?
Keith S. Taber
An obvious discrepancy is that the University of Ottawa is not Ottawa University, USA. One is in Ontario, in Canada – the other is in Kansas, in the United States. Someone who has attended one of these universities would be unlikely to be confused about which one they studied at, and graduated from.
I received an email from a journal managing editor claiming to be a highly qualified scholar (two doctorates)- for whom I can find absolutely no evidence on the web of her having ever published anything, or having any association with any university, research group, or learned society. Suspicious?
Wanted!
Information on the academic research of this woman
(Additional image elements by No-longer-here and OpenClipart-Vectors from Pixabay)
I received one of those dodgy emails from a publisher that are now part of the normal noise one has to navigate through in the Academy. The email was signed by a Dr Nicoleta Auffahrt, as Managing Editor of the 'Department of Humanities and Social Science' 'at Global Journals'. So far, nothing too suspicious.
She had read it and felt it was worthy of admiration
She had shared 'the finding' with her [unspecified] colleagues
She reported that other [unspecified] scholars of our [sic] research community had also commended 'them' [?]
She suggested that this paper demonstrated my potential to influence and inspire fellow researchers and scholars.
Two classes of academics
Now, perhaps there was a time when I might have taken some of this at face value, being naïve enough to believe that most people are basically honest, and that at least in the world of scholarship people value truth and honesty and would not casually lie.
One might expect such compliments to often hit home with academics: after all, isn't academia made up of two classes of scholars
those who suffer imposter symptom and are waiting to be found out as not belonging;
those who know their work is important and ground-breaking, deserving of being more widely known, and a sufficient cause to bring them attention, prestige, admiration, acolytes, and prizes?
The latter group, at least, would not find anything odd in receiving such unsolicited praise.
However, I've had too many emails of this kind that praise my work but which are clearly not truthful: often they either
The reference to 'our research community' was intriguing, as the letter (appended below) was structured so as to
(i) first praise me as though Dr Auffahrt was so impressed with my work that she needed to tell me; and then,
(ii) by the way, incidentally, as she was writing – she thought she would mention, "also" her role working for a publisher that led her to invite me to submit some work.
So, was it feasible that Dr Auffahrt did consider us part of the same research community? When I checked her email signature I saw she signed herself as Dr. Nicoleta Auffahrt "D.Litt in Teaching Education".
Now I was intrigued. Clearly 'teaching' and 'education' suggest that at least 'Dr' Nicoleta has a background in my general field of teaching and learning which makes a nice change from being invited to contribute on topics such as nanotechnology and various medical specialisms. Yet, this also raised some questions: what exactly is meant by 'teaching education' (cf. e.g., science education) as an academic area – was her work in teaching the subject of education or…?
Moreover, I was surprised that someone with a higher doctorate was acting as a 'managing editor' for a publisher. A D.Litt.was only likely to be awarded to a highly productive and influential scholar, and such a person might well take on editorial roles (as an editor, an associate editor, an editor-in-chief), but probably not as a managing editor.
A managing editor is employed by a publisher to oversee the administration and business side of a journal, unlike an editor who would normally being doing the intellectual work of evaluating the quality of submissions and directing the peer-review process (work which would often be seen as taking a leadership role in a research field) – and then usually only as a subsidiary post undertaken alongside an academic appointment. The prestige of the journal is often in part seen to be reflected in the university affiliations of its editors and associate editors.
There is, of course, no reason why someone who has achieved eminence in their academic field, recognised ultimately by being awarded a higher doctorate such as a D.Litt., might not decide to then make a career change and move into publishing; and, similarly, there is no reason why a publisher should not employ such a person if they were available – but it seemed an unlikely scenario. Unlikely enough for me to dig a little.
So, I did a web-search for Dr Nicoleta Auffahrt. I found her listed on one of the publisher's web-pages as part of an editorial board for social science. Her listing was:
"Ph.D. University of Pennsylvania, Master of Arts in Ottawa University, USA"
So, a Ph.D., but no mention of the much rarer and more prestigious D.Litt.degree. Of course, the web-page may be out of date, whereas perhaps Nicoleta had updated her email signature, so that proves nothing.
What was very odd though, was the limited number of web-pages that a search turned up.
Search term "Dr Nicoleta Auffahrt"/ "Dr. Nicoleta Auffahrt"
1 hit on Google (https://globaljournals.org)
Search terms Dr + "Nicoleta Auffahrt"
4 hits on Google (https://www.facebook.com; https://globaljournals.org; https://globaljournals.us; https://beta.globaljournal)
How can a successful scholar who has two doctorates and is (or, perhaps, was until recently) working in a top US university be virtually invisible on the web?
Apart from three pages for the publisher, Google only provided one other 'hit' – a 'Facebook' page. Dropping the reference to 'Dr' still only found "Nicoleta Auffahrt" on Facebook and Global Journals webpages. That seemed very strange.
I also tried using Google Scholar. Google Scholar is a specialist search engine used by academics to find research reported in journal articles, academic books, conference proceedings, on websites, and so forth. Google Scholar did not suggest a single publication (and Google Scholar is pretty liberal in what it counts as a 'publication'!) that had been authored, co-authored or edited by "Nicoleta Auffahrt".
Typically searching for an academic brings up myriad references to their publications, conference talks, involvement in research groups, links with university departments, and so forth. A search for an experienced and successful academic would be expected to turn up, at least, hundreds, indeed – likely – thousands, of hits.
This is unavoidable if you work in academia – even if for some reason a scholar chooses not to have a specific Google Scholar listing (this does not stop your work being included in the database and returned in a search – it just means you do not get a personal profile page); not to have an Academia listing; not to post on ResearchGate; not to be on Linked-In (which is a common place for those working in publishing to seek to make contacts); and does not upload their dissertations/theses to University repositories…they still cannot prevent their books and papers and conference talks being referred to here and there.
Academic prestige is, after all, largely based on publications, and publications are by definitionpublic documents. Assessment for a higher doctorate such as a D.Litt. is usually largely in terms of a scholar's published work being judged to be highly influential in their discipline or field (something that is usually only possible to judge some years after publications first appear). Moreover, one of the principle ways in which any academic is evaluated is in terms of the influence of their publications, as judged by citations – but Nicoleta Auffahrt's work does not seem to be cited anywhere. At least, Google Scholar had not found any. (No publications, and no citations.1)
So, here the only evidence I had of a person called Nicoleta Auffahrt really existing that was independent of the publisher who had contacted me was…Facebook, and that offered limited pickings.
I responded to the email (text appended below), asking Dr. Nicoleta Auffahrt about her area of work and where she had been awarded the prestigious D.Litt.
The next morning, I found I had a reply – but from someone else at the publishers. I say 'someone' else, as the email account was linked to the name Dr. Stacey J. Newman but the email was signed Dr. Nellie K. Neblett. Stacey, or was it Nellie, had ignored my questions to Nicoleta (but sent me an interesting brochure which revealed how the publisher calculated its own impact factor, but using data from the very catholic listings in Google Scholar – so vastly inflating the value compared with properly audited impact factors).
The response to my email reply to Nicoleta Auffahrt
Then a couple of days later, I had another email (appended below) from 'Dr' Auffahrt "following-up" on her earlier email, but written as if I had not replied to her – and repeating the information that she was going to be in Sydney 'next week' (it should have been 'this week' by then, if her earlier email had been correct) and again wishing my (non-existent) Christmas candles would be glorious. Given that she had asked me to confirm my affiliation with the University of Cambridge in Cambridge Uk, United Kingdom [sic, we in the U.K. tend to capitalise both letters, something one might expect an editor to appreciate – but perhaps she thought 'Cambridge Uk' was a place in the United Kingdom?], and I had done so, I was not entirely sure why she thought it useful for me to know she would be in Sydney, unless this was just 'small talk'.
I replied pointing out that,
"If you have checked your emails and seen my reply, you will have found I was asking about your research, as I wondered how it might link with mine. You have me at a disadvantage(!) as you tell me you have read some of my work, but I've not had a chance to read yours – perhaps you could direct me to some of it?"
My reply to 'Dr' Auffahrt 's second email.
So far, no response to that.
Nicoleta Auffahrt's Facebook presence
The Facebook page had not been updated since Christmas day 2021 (when a video from the University of Pennsylvania about the student-run Medical Emergency Response Team was re-posted.) According to this page: 'Dr' Auffahrt
Works at University of Pennsylvania
Worked at University of Ottawa
Studied at University of Ottawa
Studied at University of Pennsylvania
Went to Emma Hart Willard School
Lives in, and is from, Ottawa, Ontario
(I was unable to verify that there is a Emma Hart Willard School in Canada, and it is unlikely any current school would not have a website that could be picked up in a Google search, but, of course, it may have closed down or changed its name since Nicoleta studied there.)
Her Facebook page 'cover' picture (see below) is an image of 'Canada's University'.
A photograph of the Université d'Ottawa (Canada) – and the profile picture on 'Dr' Nicoleta Auffahrt's Facebook page.
The wrong Ottawa?
An obvious discrepancy is that the University of Ottawa is notOttawa University, USA (where the publisher's site claimed 'Dr' Auffahrt was awarded her M.A. degree). One is in Ontario, in Canada – the other is in Kansas, in the United States. Someone who has attended one of these universities would be unlikely to be confused about which one they studied at, and graduated from.
Some people use a Facebook page extensively to connect with friends and family. Not everyone does. Some people start a Facebook page and either abandon it, or seldom update it. So, limited information on someone's Facebook page is not of itself evidence of any wrongdoing.
Nicoleta's account was linked to two 'friends' – the University of Pennsylvania, and a Canadian ice hockey player Brendan Jacome. (His Facebook page was even less informative than Nicoleta's – but unlike her, he has quite a web presence – Google made over 2000 returns for "Brendan Jacome").
Nocolata's Facebook activity was limited to
posting a picture of 'her baby' (see below) as her profile picture, updating her cover photo, and posting a message that "Real education is only obtained through self- education" – on the same day just before before Christmas 2016;
posting that she had "Started New Job at Global Journals Incorporated" in 2o19;
and updating her profile picture and reposting the University of Pennsylvania video on Christmas day 2021.
Nicoleta's baby?
It looked like the only real clues on the Facebook page were the photographs of Nicoleta and the woman she described as her 'baby' – so, perhaps her daughter?
I tried to find any other photos that matched the image supposed to be of Nicoleta Auffahrt. I failed, so that lead did not help.
However, I soon found an image matching the picture of the other woman.
The two images above are taken from Nicoleta Auffahrt's facebook page and a public profile for one Alessandra Manganelli when she was a Ph.D. student in Brussels (this page has no new content beyond a conference attended in the UK in November 2017). A smaller version of the same photograph appears on another page at the Vrije Universiteit Brussel site.
Unlike 'Dr' Auffahrt, a quick Google for "Alessandra Manganelli" gives over 2500 hits. That is much more in line with what one might expect for an academic.
According to the web, Dr Manganelli, having completed her doctorate at the the Universities of KULeuven and Vrije Universiteit Brussel, moved to a post-doctoral position in Hamburg. It seems she undertook her doctoral studies in Engineering Science with input in Architecture from one institution (KULeuven) and in Sciences from the other (VUB). She works on areas such as Urban Governance, Social Innovation, Urban Agriculture, Local Food Policies, Urban Environmental and Climate Governance. Google Scholar lists a range of publications she has written or co-authored. That is, unlike in the case of 'Dr' Auffahrt, there is a lot of publicly available information about Dr Manganelli's research activities to support her claim to be a genuine scholar.
A Canadian connection?
Although Dr Manganelli seems to have done most of her work in Europe, one might imagine that, if she was indeed Nicoleta Auffahrt's baby, then she was perhaps born and brought up in Canada, before moving to Europe to study? However, not so: it appears Dr Manganelli is from Sienna in Italy.
Intriguingly, however, one of her publications is a book for a major academic publisher: "The Hybrid Governance of Urban Food Movements. Learning from Toronto and Brussels". She also co-authored a paper in the journal 'Critical perspectives on food guidance' on "… FoodShare Toronto´s approach to critical food guidance…". So, there is a Canadian connection.
Dr Manganelli's has her own Facebook page. (Dr Manganelli has 840 friends listed on Facebook, but Nicoleta Auffahrt is not one of them.) Her page suggests she did work at Toronto Metropolitan University from January/February to June 2017 (so, at the time when Nicoleta Auffahrt was supposedly in Ottawa before moving to Pennsylvania) – and Toronto is 'only' about 350 km from Ottawa. (Dr Manganelli's Facebook site tells visitors that she visited Toronto again in November 2022.) But Nicoleta Auffahrt seems to have posted Alessandra Manganelli's picture on her Facebook page just beforeAlessandra Manganelli arrived in Canada.
One would presumably have to have a strong connection with another person to use their photograph as your social media profile picture for five years (Nicoleta Auffahrt used Alessandra Manganelli's image as her profile picture from 22nd December 2016 till 25th December 2021). But, perhaps I was being too literal in my reading of the term 'my baby'.
Perhaps
Nicoleta and Alessandra had met somewhere (a conference, a holiday, on line?) and formed a close friendship which may even have influenced Dr Manganelli's decision to spend some time in Canada (fairly) near Nicoleta Auffahrt; then
excited with anticipation at Alessandra's imminent arrival in the country, Nicoleta had posted a picture of her friend (her 'baby') as her new profile picture.
This seems a little forced to me, but it is not completely impossible. (I had no substantive interest in 'Dr' Auffahrt's personal life {nor Dr Manganelli's} – I just wanted to find out if there was evidence she was a real person who had genuinely earned those academic qualifications.)
Given the amount of information on the web, I am fairly confident Dr Manganelli is a real person.
(I emailed her to tell her I had found her picture on Nicoleta Auffahrt's Facebook page and asked if she had an email contact for Nicoleta Auffahrt. No reply (as yet) but Dr Manganelli is under no obligation to reply to emails from strangers asking her about her friends.)
I am less sure about 'Dr' Nicoleta Auffahrt.
I also emailed the registry at the University of Pennsylvania to say I had been contacted by someone claiming to hold a Ph.D. from the University, where I had suspicions about this, and asked if there was a public listing of Ph.D. holders that could be checked. So, far no response (beyond an automatic reply with a case number pointing out that a response "may take up to 3-5 business days", sent over two weeks ago). Perhaps the University of Pennsylvania does not concern itself with people who are possibly falsely claiming to hold its doctorates.*
Conclusion?
Perhaps, Nicoleta Auffahrt is a real person who does hold the degrees she claims, including a higher doctorate, despite having no scholarly trace on the web (though this seems incredible to the point of being virtually impossible), and does work for 'Global Journals'; and perhaps she did write the email telling me she was visiting Sydney (why tell me that?) and wishing me glorious Christmas candles (why say that weeks after Christmas?)… and then also writing the second email email ignoring my reply and repeating the information about Sydney and candles? I guess this is not impossible, just extremely unlikely. And if this is the case, and if she is so keen to 'develop an academic relationship' with me, then why does she ignore my replies and my request to learn more about her work?
Alternatively, perhaps Nicoleta Auffahrt is a real person with a genuine, if seldom updated, Facebook page, and a close relationship of some kind (which is genuinely none of my business) with Dr Alessandra Manganelli, but her identify has been 'borrowed' by Global Journals. So, perhaps, there is wrongdoing, but Nicoleta Auffahrt is totally innocent of this.
It seems more likely to me that the Facebook page is a sham set up to give some kind of minimal web presence to 'Dr' Auffahrt (a fictitious Managing Editor at Global Journals), and that there is no Nicoleta Auffahrt (and that Dr Manganelli's image was simply arbitrarily sourced from the web somewhere without her knowledge).
Of course, I may be wrong, but there is certainly something dodgy about communications from this publisher, as the supposed managing editor seems to share her email account with Dr. Stacey J. Newman / Dr. Nellie K. Neblett – and checking back through old email I found another invitation (appended below) from the same email addresssupposedly from a Dr. Gisela Steins (there is a real academic with this name who is a psychology professor in Germany and is listed on the editorial board of the Global Journal of Human-Social Science).
Congratulations on your role as Managing Editor, Department of Humanities and Social Science at Global Journals. This sounds a prestigious and challenging position. I hope you enjoy Sydney – I've not been there myself. I was a little confused by your remark about candles, as I had always assumed most Australians celebrated Christmas at the same time as in Western Europe – I am afraid Christmas already seems a memory here.
I wonder what you found of particular interest in the paper – perhaps you would be prepared to share what it is you found especially of value in this work?
In answer to your question, I am now retired from my teaching role. I maintain an affiliation with my Faculty as an Emeritus Officer of the University, and intend to follow my own scholarly interests for as long as I am able.
Perhaps this links to your own research? I hope you would be kind enough, in return, to answer a question for me. I was intrigued to see that you had a higher doctorate, a D. Litt. in Teaching Education, so clearly your background is relevant to my work. I was wondering where you were awarded that? I see from the journal publisher' web-pages that you were awarded your Ph.D. from the University of Pennsylvania and your Master of Arts from Ottawa University, USA, but it does not mention your D.Litt. Is 'Teaching Education' meant to be an abbreviation for teaching and education or was your degree specifically related to teacher education? In my national context a D. Litt. would usually only be awarded after a highly positive evaluation of a portfolio of post-doctoral publications, but I believe in the U.S. some universities offer this as an outcome of a thesis-based programme. I would be interested to know more about your area of work – in particular the body of work for which the D.Litt. was awarded, and how it links to my own scholarship and research.
Best wishes
Keith
What is this obsession with Christmas candles?Praise (supposedly) from a psychology professor who found time to read my 'remarkable' work.
Update: Dr. Nicoleta Auffahrt succeeded by her doppelgänger?
My thanks to Dr. Murat Siviloglu for forwarding to me this extract (above) from an invitation he received from the current Managing Editor of the Global Journal of Human-Social Science. It seems perhaps "Dr Nicoleta Auffahrt" has moved on form her role, and now invitations are being sent out by "Dr Carolyn C. Mitchell". According to the invitation, Mitchell, like Aufffahrt holds the higher doctorate of a D.Litt., again in the odd subject of 'Teaching Education'.
The only references to a "Dr [or Dr.] Carolyn C. Mitchell"that showed on a web-search were on the Journal publisher's sites. I could not find anyone called Carolyn Mitchell who seemed to have a D.Litt., so, like her predecessor, Mitchell seems to have achieved high academic status without any visible trace of research and scholarship. 1
Mitchell is also a 'dead ringer' for Auffahrt, as their profile pictures seem, well, identical.
And the similarities do not stop there. According to the Journal website, "Dr Carolyn C. Mitchell" also holds the degrees of
"Ph.D. University of Pennsylvania, Master of Arts in Ottawa University, USA".
It seems that when appointing senior editors, Global Journals certainly 'go for a type' as they say.
1 It may seen obvious that if someone has not published any work, then no one can be citing them. That is fair enough. However, Google Scholar will find citations in work that is accessible on the web to work that is not itself found on the web – for example, references made to books that were published many years ago and have never been digitised, or to conference papers that were distributed at talks in hard copy, but have never been included in web repositories.
* Update. On 17th March I received a reply, from a Student Service Center Counselor, to my enquiry from eight weeks earlier:
Sorry for the delay as the registrar's office is months behind on email requests. We have been tasked with assisting to clear their portal. Below is what we typically send 3rd party requests for information:
Thank you for contacting Student Registration and Financial Services (SRFS). We have received your education verification request for (INSERT STUDENT NAME) from the University of Pennsylvania. Third-Party education verifications are required to go through the National Student Clearinghouse (NSC). Please use this link: https://secure.studentclearinghouse.org/vs/Index to place your request. Penn's school code is…
email from University of Pennsylvania
When I investigated the National Student Clearinghouse website, I found I needed to first register as either a representative of a 'company' or as a student seeking to verify my own record.
Screenshot of part of a webpage of the National Student Clearinghouse
"The mission of the National Student Clearinghouse is to serve the education and workforce communities and all learners with access to trusted data, related services, and insights."
https://www.studentclearinghouse.org/about/
It seems there is no facility for someone approached by a publisher to check the veracity of an editor's claimed qualifications.
Particle intuitions may not match scientific models
Keith S. Taber
Sophia was a participant in the Understanding Science Project. I first talked to her when she was in Y7, soon after she began her secondary school course.
One of the first topics she studied in her science was 'solids, liquids and gases', where she had learnt,
that solids are really hard and they stay together more, and then liquids are close together but they move around, and gases are really free and they just go anywhere
She had studied a little about the topic in her last year of primary school (Y6), but now she was being told
about the particles…the things that make – the actual thing, make them a solid, and make them a gas and make them a liquid
Particle theory, or basic kinetic theory, is one of the most fundamental theories of modern science. In particular, much of what is taught in school chemistry is explained in terms of theories involving how the observed macroscopic properties emerge from the characteristics and interactions of conjectured sub-microscopic particles that themselves often have quite unfamiliar properties. This makes the subject very abstract, challenging, and tricky to teach (Taber, 2013a).
Particle theory is often introduced in terms of the states of matter. Strictly there are more than three states of matter (plasma and Bose-Einstein condensates are important in some areas of science) but the familiar ones, and the most important in everyday phenomena, are solid, liquid and gas.
The scientific account is, in simple terms, that
different substances are made up of different types of particle
the different states of matter of a single substance have the same particles arranged differently
These are very powerful ideas, even if there are many complications. For example,
the terms solid, liquid and gas only strictly apply to pure samples of a single substance, not mixtures (so not, for example, to bronze, or honey, or, milk, or ketchup, or even {if one is being very pedantic} air or sea water. And cats (please note, BBC) are completely inadmissible. )
common salt is an example of a pure substance, that none-the-less is considered to be made up of more than one type of particle
This reflects a common type of challenge in teaching science – the full scientific account is complex and nuanced, and not suitable for presenting in an introductory account; so we need to teach a simplified version that introduced the key ideas, and then only once this is mastered by learners are they ready to develop a more sophisticated understanding.
Yet, there is a danger that students will learn the simplified models as truths supported by the authority of science – and then later have difficulty shifting their thinking on. This is not only counter-productive, but can be frustrating and de-motivating for learners who find hard-earned knowledge is not as sound as they assumed.
One response to this is to teach science form very early in a way that is explicit about how science builds models of the natural world: models that are often simplifications which are useful but need to be refined and developed to become powerful enough to expand the range of contexts and examples where they can be applied. That is, students should learn they are being taught models that are often partial or imperfect, but that is just a reflection of how science works, developing more sophisticated understanding over time (Taber, 2017).
Sophia confirmed that the iron clamp stand near where she was sitting would have particles in it, as would a lump of ice.
Are they the same particles in the ice as the iron?
Yeah, because they are a solid, but they can change.
Ah, how can they change?
Cause if, erm, they melted they would be a liquid so they would have different particles in.
Right, so the iron is a solid,
Uh hm.
So that's got one type of particle?
Yeah.
And ice is also a solid?
Yeah.
So that has the same sort of particles?
Yeah, but they can change.
The ones in the ice?
Mm,
To a learner just meeting particle theory for the first time, it may seem just as feasible that the same type of particle is found in one state as in one substance.
In the scientific model, we explain that different substances contain different types of particles, whereas different states of the same substance contain different arrangements of the same particles: but this may not be intuitively obvious to learners.1 It seemed Sophia was thinking that the same particles would be in different liquids, but a change of state led to different particles. This may seem a more forced model to a teacher, but then the teacher is already very familiar with the scientific account, and also has an understanding of the nature of those particles (molecules, ions, atoms – with internal structure and charges that interact with each other within and between the particles) – which are just vague, recently imagined, entities to the novice.
Sophia seemed to misunderstood or misremembered the model she had been taught, but to a novice learner these 'particles' have no more immediate referent than an elf or an ogre and would be considerably more tenuous than a will-o'-the-wisp.
Sophia seemed to have an alternative conception, that all solids have one type of particle, and all liquids another. If I had stopped probing at that point I might have considered this to be her thinking on the matter. However, when one spends time talking to students it soon becomes clear that often they have ideas that are not fully formed, or that may be hybrids of different models under consideration, and that often as they talk they can talk themselves into a position.
So, if I melted the ice – that changes the particles in the solid?
Well they are still the same particles but they are just changing the way they act…
Oh.
How do they change?
A particle in a liquid [sic, solid] is all crammed together and don't move around, but in a liquid they can move around a little but they are still close and, can, you can pour a liquid, where you can't a solid, because they can move in.
Okay, so if I have got my ice, that's a solid, and there are particles in the ice, and they behave in a certain way, and if the ice melts, the particles behave differently?
Yeah.
Do you know why they behave differently in the liquid?
No. {giggles} So, they can, erm
• • • • • • • • • • • • [A pause of approximately 12 s]
They've more room cause it's all spread out more1, whereas it would be in a clump
The literature on learners conceptions often suggests that students have this or that conception, or (when survey questions are used) that this percentage thinks this, and that percentage thinks that (Taber, 2013b). That this is likely to be a simplification seems obvious is we consider what thinking is – whatever thought may be, is it a dynamic process, something that moves along. Our thinking is, in part, resourced by accessing what we have represented in memory, but it is not something fixed – rather something that shifts, and that often becomes more sophisticated and nuanced as we explore a focus in greater depth.
I think Sophia did seem to have an intuition that there were different types of particles in different states of matter, and that therefore a change of state meant the particles themselves changed in some way. As I probed her, she seemed to shift to a more canonical account where change of state involved a change in the arrangement or organisation of particles rather than their identity.
This may have simply been her gradually bringing to mind what she had been taught – remembering what the teacher had said. It is also possible that the logic of the phenomenon of a solid becoming a liquid impressed on her that they must be the same particles. I suspect there was a little of both.
When interviewing students for research we inevitably change their thinking and understanding to some extent (hopefully, mostly in a beneficial way!) (If only teachers had time to engage each of their students in this way about each new topic they might both better understand their students' thinking, and help reinforce what has been taught.)
Did Sophia 'have a misconception'? 1 What did she 'really think'? That, surely, is to oversimplify.
She presented with an alternative conception, that under gentle questioning she seemed to talk /think herself out of. The extent to which her shift in position reflected further recall (so, correcting her response) or 'thinking through' (so, developing her understanding) cannot be known. Likely there was a little of both. What memory research does suggest is that being asked to engage in and think about this material will have modified and reinforced her memories of the material for the future.
Johnson, P. M. (2012). Introducing Particle Theory. In K. S. Taber (Ed.), Teaching Secondary Chemistry (Second ed., pp. 49-73). Association for Science Education/John Murray.
1 Actually, the particles in a liquid are not substantially spread further apart than in a solid. (Indeed, when ice melts the water molecules move closer together on average.) Understanding melting requires an appreciation of the attractions between particles, and how heating provides more energy for the particles. This idea of increased separation on melting is therefore something of an alternative conception, if one that is sometimes encouraged by the diagrams in school textbooks.
Teaching an introductory particle theory based on the arrangement of particles in different states, without reference to the attractions between particles is problematic as it offers no rational basis for why condensed states exists, and why energy is needed to disrupt them – something highlighted in the work of Philip Johnson (2012).
Sotakova, Ganajova and Babincakova (2020) rightly criticised experiments into enquiry-based science teaching on the grounds that such studies often used control groups where the teaching methods had "not been clearly defined".
So, how did they respond to this challenge?
Consider a school science experiment where students report comparing the rates of reaction of 1 cm strips of magnesium ribbon dropped into: (a) 100 ml of hydrochloric acid of 0.2 mol/dm3 concentration at a temperature of 28 ˚C; and (b) some unspecified liquid.
This is a bit like someone who wants to check they are not diabetic, but – being worried they are – dips the test strip in a glass of tap water rather than their urine sample.
Basic premises of scientific enquiry and reporting are that
when carrying out an experiment one should carefully manage the conditions (which is easier in laboratory research than in educational enquiry) and
one should offer detailed reports of the work carried out.
In science there is an ideal that a research report should be detailed enough to allow other competent researchers to repeat the original study and verify the results reported. That repeating and checking of existing work is referred to as replication.
Replication in science
In practice, replication is more problematic for both principled and pragmatic reasons.
It is difficult to communicate tacit knowledge
It has been found that when a researcher develops some new technique, the official report in the literature is often inadequate to allow researchers elsewhere to repeat the work based only on the published account. The sociologist of science, Harry Collins (1992) has explored how there may be minor (but critical) details about the setting-up of apparatus or laboratory procedures that the original researchers did not feel were significant enough to report – or even that the researchers had not been explicitly aware of. Replication may require scientists to physically visit each others' laboratories to learn new techniques.
This should not be surprising, as the chemist and philosopher Michael Polanyi (1962/1969) long ago argued that science relied on tacit knowledge (sometimes known as implicit knowledge) – a kind of green fingers of the laboratory where people learn ways of doing things more as a kind of 'muscle memory' than formal procedural rules.
Novel knowledge claims are valued
The other problem with replication is that there is little to be gained for scientists by repeating other people's work if they believe it is sound, as journals put a premium on research papers that claim to report original work. Even if it proves possible to publish a true replication (at best, in a less prestigious journal), the replication study will just be an 'also ran' in the scientific race.
Copies need not apply!
Scientific kudos and rewards go to those who produce novel work: originality is a common criterion used when evaluating reports submitted to research journals
(Image by Tom from Pixabay)
Historical studies (Shapin & Schaffer, 2011) show that what actually tends to happen is that scientists – deliberately – do not exactly replicate published studies, but rather make adjustments to produce a modified version of the reported experiment. A scientist's mind set is not to confirm, but to seek a new, publishable, result,
they say it works for tin, so let's try manganese?
they did it in frogs, let's see if it works in toads?
will we still get that effect closer to the boiling point?
the outcome in broad spectrum light has been reported, but might monochromatic light of some particular frequency be more efficient?
they used glucose, we can try fructose
This extends (or finds the limits of) the range of application of scientific ideas, and allows the researchers to seek publication of new claims.
I have argued that the same logic is needed in experimental studies of teaching approaches, but this requires researchers detailing the context of their studies rather better than many do (e.g., not just 'twelve year olds in a public school in country X'),
"When there is a series of studies testing the same innovation, it is most useful if collectively they sample in a way that offers maximum information about the potential range of effectiveness of the innovation. There are clearly many factors that may be relevant. It may be useful for replication studies of effective innovations to take place with groups of different socio-economic status, or in different countries with different curriculum contexts, or indeed in countries with different cultural norms (and perhaps very different class sizes; different access to laboratory facilities) and languages of instruction …It may be useful to test the range of effectiveness of some innovations in terms of the ages of students, or across a range of quite different science topics. Such decisions should be based on theoretical considerations.
…If all existing studies report positive outcomes, then it is most useful to select new samples that are as different as possible from those already tested…When existing studies suggest the innovation is effective in some contexts but not others, then the characteristics of samples/context of published studies can be used to guide the selection of new samples/contexts (perhaps those judged as offering intermediate cases) that can help illuminate the boundaries of the range of effectiveness of the innovation."
The exception, that tests the 'scientists do not simply replicate' rule, is when it is suspected that a research finding is wrong. Then, an attempt at replication might be used to show a published account is flawed.
For example, when 'cold fusion' was announced with much fanfare (ahead of the peer reviewed publications reporting the research) many scientists simply thought it was highly unlikely that atomic energy generation was going to be possible in fairly standard glassware (not that unlike the beakers and flasks used in school science) at room temperature, and so that there was a challenge to find out what the original researchers had got wrong.
"When it was claimed that power could be generated by 'cold fusion', scientists did not simply accept this, but went about trying it for themselves…Over a period of time, a (near) consensus developed that, when sufficient precautions were made to measure energy inputs and outputs accurately, there was no basis for considering a new revolutionary means of power generation had been discovered.
Of course, one failed replication might just mean the second team did not quite do the experiment correctly, so it may take a series of failed replications to make the point. In this situation, being the first failed replication of many (so being first to correct the record in the literature) may bring prestige – but this also invites the risk of being the only failed replication(so, perhaps, being judged a poorly executedreplication) if subsequently other researchers confirm the fidnings of the original study!
So, a single attempt at replication is nether enough to definitely verify nor reject a published result. What all this does show is that the simple notion that there are crucial or critical experiments in science which once reported immediately 'prove' something for all time is a naïve oversimplification of how science works.
Experiments in education
Experiments are often the best way to test ideas about natural phenomena. They tend to be much less useful in education as there are often many potentially relevant variables that usually cannot be measured, let alone controlled, even if they can be identified.
Without proper control, you do not have a meaningful experiment.
Without a detailed account of the different treatments, and so how the comparison condition is different from the experimental condition, you do not have a useful scientific report, but little more than an anecdote.
Challenges of experimental work in classrooms
Despite this, the research literature includes a vast number of educational studies claiming to be experiments to test this innovation or that (Taber, 2019). Some are very informative. But many are so flawed in design or execution that their conclusions rely more on the researchers' expectations than a logical chain of argument from robust evidence. They often use poorly managed experimental conditions to find differences in learning outcomes between groups of students that are initially not equivalent. 1 (Poorly managed?: because there are severe – practical and ethical – limits on the variables you can control in a school or college classroom.)
Statistical tests are then used which would be informative had there been a genuinely controlled experiment with identical starting points and only the variable of interest being different in the two conditions. Results are claimed by ignoring the inconvenient fact that studies use statistical tests that, strictly, do not apply in the actual conditions studied! Worse than this, occasionally the researchers think they should have got a positive result and so claim one even when the statistical tests suggests otherwise (e.g., read 'Falsifying research conclusions')! In order to try and force a result, a supposed innovation may be compared with control conditions that have been deliberately framed to ensure the learners in that condition are not taught well!
A common problem is that it is not possible to randomise students to conditions, so only classes are assigned to treatments randomly. As there are usually only a few classes in each condition (indeed, often only one class in each condition) there are not enough 'units of analysis' to validly use statistical tests. A common solution to this common problem, is…to do the tests anyway, as if there had been randomisation of learners. 2 The computer that crunches the numbers follows a programme that has been written on the assumption researchers will not cheat, so it churns out statistical results and (often) reports significant outcomes due to a misuse of the tests. 3
This is a bit like someone who wants to check they are not diabetic, but being worried they are, dips the test strip in a glass of tap water rather than their urine sample. They cannot blame the technology for getting it wrong if they do not follow the proper procedures.
I have been trying to make a fuss about these issues for some time, because a lot of the results presented in the educational literature are based upon experimental studies that, at best, do not report the research in enough detail, and often, when there is enough detail to be scrutinised, fall well short of valid experiments.
I have a hunch that many people with scientific training are so convinced of the superiority of the experimental method, that they tacitly assume it is better to do invalid experiments into teaching, than adopt other approaches which (whilst not as inherently convincing as a well-designed and executed experiment) can actually offer useful insights in the complex and messy context of classrooms. 4
So, it is uplifting when I read work which seems to reflect my concerns about the reliance on experiments in those situations where good experiments are not feasible. In that regard, I was reading a paper reporting a study into enquiry-based teaching (Sotakova, Ganajova & Babincakova, 2020) where the authors made the very valid criticism:
"The ambiguous results of research comparing IBSE [enquiry-based science education] with other teaching methods may result from the fact that often, [sic] teaching methods used in the control groups have not been clearly defined, merely referred to as "traditional teaching methods" with no further specification, or there has been no control group at all."
Now, I do not want to appear to be the pot calling the kettle black myself, so before proceeding I should acknowledge that I was part of a major funded research project exploring a teaching innovation in lower secondary science and maths teaching. Despite a large grant, the need to enrol a sufficient number of classes to randomise to treatments to allow statistical testing meant that we had very limited opportunities to observe, and so detail, the teaching in the control condition, which was basically the teachers doing their normal teaching, whilst the teachers of the experimental classes were asked to follow a particular scheme of work.
Results from a randomised trial showing the range of within-condition outcomes (After Figure 5, Taber, 2019)
In the event, the electricity module I was working on produced almost identical mean outcomes as the control condition (see the figure). The spread of outcomes was large, in both sets of conditions – so, clearly, there were significant differences between individual classes that influenced learning: but these differences were even more extreme in the condition where the teachers were supposed to be teaching the same content, in the same order, with the same materials and activities, than in the control condition where teachers were free to do whatever they thought best!
The main thing I learned from this experience is that experiments into teaching are highly problematic.
Anyway, Sotakova, Ganajova and Babincakova were quite right to point out that experiments with poorly defined control conditions are inadequate. Consider a school science experiment designed by students who report comparing the rates of reaction of 1 cm strips of magnesium ribbon dropped into
(a) 100 ml of hydrochloric acid of 0.2 mol/dm3 concentration at a temperature of 28 ˚C; and
(b) some unspecified liquid.
A science teacher might be disappointed with the students concerned, given the limited informativeness of such an experiment – yet highly qualified science education researchers often report analogousexperiments where some highly specified teaching is compared with instruction that is not detailed at all.
The pot decides to follow the example of the kettle
So, what did Sotakova and colleagues do?
"Pre-test and post-test two-group design was employed in the research…Within a specified period of time, an experimental intervention was performed within the experimental group while the control group remained unaffected. The teaching method as an independent variable was manipulated to identify its effect on the dependent variable (in this case, knowledge and skills). Both groups were tested using the same methods before and after the experiment…both groups proceeded to revise the 'Changes in chemical reactions' thematic unit in the course of 10 lessons"
In the experimental condition, enquiry-based methods were used in five distinct activities as a revision approach (an example activity is detailed in the paper). What about the control conditions?
"…in the control group IBSE was not used at all…In the control group, teachers revised the topic using methods of their choice, e.g. questions & answers, oral and written revision, textbook studying, demonstration experiments, laboratory work."
So, the 'control' condition involved the particular teachers in that condition doing as they wished. The only control seems to be that they were asked not to use enquiry. Otherwise, anything went – and that anything was not necessarily typical of what other teachers might have done. 6
This might have involved any of a number of different activities, such as
or combinations of them. Call me picky (or a blackened pot), but did these authors not complain that
"The ambiguous results of research comparing IBSE [enquiry-based science education] with other teaching methods may result from the fact that often…teaching methods used in the control groups have not been clearly defined…"
Sotakova, Ganajova & Babincakova, 2020, p.500
Hm.
Work cited
Collins, H. (1992). Changing order: Replication and induction in scientific practice. University of Chicago Press.
Polanyi, M. (1962/1969). The unaccountable element in science. In M. Greene (Ed.), Knowing and Being: Essays by Michael Polanyi (pp. 105-120). University of Chicago.
Shapin, S., & Schaffer, S. (2011). Leviathan and the Air-Pump: Hobbes, Boyle, and the Experimental Life. Princeton University Press.
1 A very common approach is to use a pre-test to check for significant differences between classes before the intervention. Where differences between groups do not reach the usual criterion for being statistically significant (probability, p<0.05) the groups are declared 'equivalent'. That is, a negative result in a test for unlikely differences is treated inappropriately as an indicator of equivalence (Taber, 2019).
2 So, for example, a valid procedure may be to enter the mean class scores on some instrument as data, but what are actually entered are the individual students scores as though the students can be treated as independent units rather than members of a treatment class.
Some statistical tests lead to a number (the statistic) which is then compared with the critical value that reaches statistical significance as listed in a table. The number in the table selected depends on the number of 'degrees of freedom' in the experimental design. Often that should be the determined by the number of classes involved in the experiment – but if instead the number of learners is used, a much smaller value of the calculated statistic will seem to reach significance.
3Some of these studies would surely have given positive outcomes even if they had been able to randomise students to conditions or used a robust test for initial equivalence – but we cannot use that as a justification for ignoring the flaws in the experiment. That would be like claiming a laboratory result was obtained with dilute acidwhen actuallyconcentrated acid was used – and then justifying the claim by arguing that the same result might have occurred with dilute acid.
4 Consider, for example, a case study that involves researchers in observing teaching, interviewing students and teachers, documenting classroom activities, recording classroom dialogue, collecting samples of student work, etc. This type of enquiry can offer a good deal of insight into the quality of teaching and learning in the class and the processes at work during instruction (and so whether specific outcomes seem to be causally linked to features of the innovation being tested).
Critics of so-called qualitative methods quite rightly point out that such approaches cannot actually show any one approach is better than others – only experiments can do that. Ideally, we need both types of study as they complement each other offering different kinds of information.
The problem with many experiments reported in the education literature is that because of the inherent challenges of setting up genuinely fair testing in educational contexts they are not comparing like with like, and often it is not even clear what the comparison is with! Probably this can only be avoided in very large scale (and so expensive) studies where enough different classrooms can be randomly assigned to each condition to allow statistics to be used.
Why do researchers keep undertaking small scale experimental studies that often lack proper initial equivalence between conditions, and that often have inadequate control of variables? I suggest they will continue to do so as long as research journals continue to publish the studies (and allow them to claim definitive conclusions) regardless of their problems.
5 At a time when cooking was done on open fires, using wood that produced much smoke, the idiom was likely easily understood. In an age of ceramic hobs and electric kettles the saying has become anachronistic.
From the perspective of thermal physics, black cooking pots (rather than shiny reflective surfaces) may be a sensible choice.
6 So, the experimental treatment was being compared with the current standard practice of the teachers assigned to the control condition. It would not matter so much that this varies between teachers, nor that we do not know what that practice is, if we could be confident that the teachers in the control condition were (or were very probably) a representative sample of the wider population of teachers – such as a sufficiently large number of teachers randomly chosen from the wider population (Taber, 2019). Then we would at least know whether the enquiry based approach was an improvement on current common practice.
All we actually know is how the experimental condition fared in comparison with the unknown practices of a small number of teachers who may or may not have been representative of the wider population.
One of the phrases I return to a good deal on these pages is 'making the unfamiliar familiar' because a large part of science teaching is indeed about introducing scientific concepts that are currently unfamiliar to learners (oxidising agents, the endoplasmic reticulum, moments of inertia…the list is extensive!), so they become familiar to learners.
So, teachers use analogies, metaphors, narratives, images, models, and so forth, to help link something new (and often abstract) to whatever 'interpretive resources' the teacher thinks the learners have available to make sense of what is still novel to them.
This process can certainly go wrong – learners can confuse what is meant as a kind of stepping stone towards a scientific concept (e.g., a teaching analogy, or a simplified model) for the concept itself. So, as just one example, dot and cross figures showing electron transfer between atoms that are sometimes employed to help introduce the idea of ionic bonding come to be confused with ionic bonding itself – so that learners come to wrongly assumeelectron transfer is a necessary part of ionic bond formation – or, worse, that ionic bonding is electron transfer (e.g., Taber, 1994).
The familiarisation devices used in teaching, then, could be seen as a kind of 'dumbing down' as they work with the familiar and concrete or easily visualised or represented, and fall short of the scientific account. Yet, this approach may be necessary to produce meaningful learning (rather than rote learning that is not understood, and is soon forgotten or becomes confused).
Scientists need to make the unfamiliar familiar
So, it is worth pointing out that scientists themselves, not just science teachers and journalists, often appreciate the need to introduce new ideas in terms their readers can imagine and make sense of. I have noted lots of examples from such contexts on this site. 1 Now this happens a lot in 'popular' science communication, when a scientist is writing for a general audience or being interviewed by a journalist.
But it also happens when scientists are primarily addressing their peers in the scientific research community. One of my favourite examples is the liquid drop model of the nucleus.
The atomic nucleus is like a drop of liquid because…
Lise Meitner had been working with Otto Hahn and Fritz Strassmann in the Kaiser Wilhelm Gesellschaft in Berlin, Germany, where they were investigating properties of radioactive elements. It was known some heavy elements would decay through processes such as alpha decay, which leads to an element with an atomic number two less than the starting material. 2 Their laboratory results, however, suggested that bombarding uranium with neutrons would directly lead to elements much less massive than the uranium.
By the time these results were available, Meitner had left Germany for her own safety. She would have been subject to persecution by the Nazis – quite likely she would have been removed from her scientific work, and then later sent to one of the concentration camps before being murdered as part of the genocide carried out against people the Nazis identified as Jews. 3
Hahn and Strassmann sent Meitner their findings – which did not make sense in terms of the nuclear processes known at the time. With her nephew, Otto Robert Frisch, Meitner decided the results provided evidence of a new phenomenon based on a previously unexpected mechanism of nuclear decay – fission. Nuclear fission was the splitting of a heavy nucleus into two smaller nuclei of roughly similar mass (where alpha decay produced a daughter nearly as heavy along with the very light helium nucleus).
Meitner and Frisch explained this by suggesting a new model or analogy for the nucleus:
"On account of their close packing and strong energy exchange, the particles in a heavy nucleus would be expected to move in a collective way which has some resemblance to the movement of a liquid drop. If the movement is made sufficiently violent by adding energy, such a drop may divide itself into two smaller drops."
Meitner & Frisch, 1939
This was published in the top scientific journal, Nature – but this was no barrier to the scientists using an everyday, familiar, analogy to explain their ideas.
An energetic liquid drop may fission (Image by Gerhard Bögner from Pixabay)
Chemistry and the beautiful game?
A much later example appeared in the same journal when Kroto and colleagues published their paper about the newly reported allotrope of carbon (alongside graphite and diamond) with formula C60 by including a photograph in their article. A photograph of…an ordinary football!
They used the football to explain the suggested molecular geometry of C60, which they referred to as buckinsterfullerene,
"Concerning the question of what kind of 60-carbon atom structure might give rise to a superstable species, we suggest a truncated icosahedron, a polygon with 60 vertices and 32 faces, 12 of which are pentagonal and 20 hexagonal. This object is commonly encountered as the football shown in Fig. 1."
Kroto, et al., 1985
A football (notice the panels are hexagons and pentagons 4). (Image by NoName_13 from Pixabay)
Kroto and colleagues submitted a photograph like this to be published as a figure in their scientific report of the discovery of the buckminsterfullerene allotrope of carbon
What could be more familiar to people than the kind of ball used in Association Football ('soccer')? (Even if this is not really a truncated icosahedron 4). Their figure 1 showed,
"A football (in the United States, a soccerball) on Texas grass. The C60 molecule featured in this letter is suggested to have the truncated icosahedral structure formed by replacing each vertex on the seams of such a ball by a carbon atom."
Kroto, et al., 1985
The scientists explained they had come across the suggested shape when searching for a viable molecular structure that fitted the formula (sixty carbon atoms and nothing else) and which would also satisfy the need for carbon to be tetravalent. They investigated the works of the designer/architect Richard Buckminster Fuller, famous for his geodesic domes.
A stamp commemorating the life and works of Richard Buckminster Fuller and representing geodesic domes.
Thus they provisionally called the new substance buckinsterfullerene, albeit they acknowledged this name might be something of a 'mouthful', so to speak,
"We are disturbed at the number of letters and syllables in the rather fanciful but highly appropriate name we have chosen in the title [of their paper] to refer to this C60 species. For such a unique and centrally important molecular structure, a more concise name would be useful. A number of alternatives come to mind (for example, ballene, spherene, soccerene, carbosoccer), but we prefer to let this issue of nomenclature be settled by consensus."
Kroto, et al., 1985
We now know that the term 'buckyballs' has become popular, but only as a shorthand for the mooted name: buckinsterfullerene. (Later other allotropic form of carbon based on closed shell structures were discovered – e.g., C70. The shorter term fullerenes refers to this group of allotropes: buckminsterfullerene is one of the fullerenes.)
I recall seeing a recording of an interview with Harry Kroto where he suggested that the identification of the structure with the shape of a football came during a transatlantic phone call. What I would love to know is whether Kroto and his co-authors were being somewhat mischievous when they decided to illustrate the idea by asking the world's most famous science journal to publish a figure that was not some abstract scientific representation, but just a photograph of a football. Whether or not they were expecting kick-back [sorry] from the journal's peer reviewers and editor, it did not act as an impediment to Curl, Kroto and Smalley being awarded the 1996 Nobel prize for chemistry "for their discovery of fullerenes" (https://www.nobelprize.org/prizes/chemistry/1996/summary/).
Work cited:
Kroto, H., Heath, J., O'Brien, S., Curl, R. F. & Smalley, R. E. (1985) C60: Buckminsterfullerene. Nature, 318, 162-163. https://doi.org/10.1038/318162a0
Meitner, L., Frisch, O.R. (1939) Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction. Nature, 143, 239-240. https://doi.org/10.1038/143239a0
1 There is a range of tactics that can be used to help communicate science. Generally, to the extent these make abstract ideas accessible, they are presentations that fall short of the scientific account – and so they are best seen as transitional devices to offer intermediate understandings that will be further developed.
I have included on the site a range of examples I have come across of some of the ways in which science is taught and communicated through analogies, metaphors and so forth. Anthropomorphism is when non-human objects are discussed as if having human feelings intentions and so forth.
2 The radioactive decay of unstable but naturally occurring uranium and thorium takes place by a series of nuclear processes, each producing another radioactive species, till a final step produces an isotope which can be considered stable – 206Pb (from decay of 238U), 207Pb (from decay of 235U) or 208Pb (from decay of 232Th). By a pure coincidence of language (a homograph), in English, these radioactive decay cascades lead to lead (Pb).
3 That is not to say most of those murdered because they were Jewish would not have self-identified as such, but rather that the Third Reich had its own racist criteria (established by law in 1935) for deciding who should be considered a Jew based on unscientific notions of bloodlines – so, for example, being a committed and practising Christian was no protection if the Nazis decided you were from a Jewish family.
(Nazi thinking also drew on a very influential but dangerous medical analogy of the volk (people) as a body that allowed those not considered to belong to the body to be seen as akin to foreign microbes that could cause disease unless eliminated.)
4 Of course a football is not a truncated icosahedron – it is intended to be, as far as possible, spherical! The pentagons and hexagons are made of a flexible material, and within them is a 'bladder' (nowadays this is just a metaphor!) which is an elastic sphere that when inflated presses against the outer layers.
If a football was built using completely rigid panels, then it would be a truncated icosahedron. However, such a 'ball' would not roll very well, and would likely cause some nasty head injuries. Presumably the authors were well aware of this, and assumed their readers would see past the problem with this example and spontaneously think of some kind of idealised, if far from ideal, football.
It may be difficult to know what counts as an alternative conception in some topics – and sometimes research does not make it any clearer
Keith S. Taber
If a reader actually thought the researchers themselves held these alternative conceptions then one could have little confidence in their ability to distinguish between the scientific and alternative conceptions of others
I recently published an article here where I talked in some detail about some aspects of a study (Tarhan, Ayyıldız, Ogunc & Sesen, 2013) published in the journal Research in Science and Technological Education. Despite having a somewhat dodgy title 1, this is a well respected journal published by a serious publisher (Routledge/Taylor & Francis). I read the paper because I was interested in the pedagogy being discussed (jigsaw learning), but what promoted me to then write about it was the experimental design: setting up a comparison between a well-tested active learning approach and lecture-based teaching. A teacher experienced in active learning techniques taught a control group of twelve year old pupils through a 'traditional' teaching approach (giving the children notes, setting them questions…) as a comparison condition for a teaching approach based on engaging group-work.
The topic being studied by the sixth grade, elementary school, students was physical and chemical changes.
I did not discuss the outcomes of the study in that post as my focus there was on the study as possibly being an example of rhetorical research (i.e., a demonstration set up to produce a particular outcome, rather than an open-ended experiment to genuinely test a hypothesis), and I was concerned that the control conditions involved deliberately providing sub-optimal, indeed sub-standard, teaching to the learners assigned to the comparison condition.
The researchers actually tested the outcome of their experiment in two ways (as well as asking students in the experimental condition about their perceptions of the lessons), a post-test taken by all students, and "ten-minute semi-structured individual interviews" with a sample of students from each condition.
Analysis of the post-test allowed the researchers to identify the presence of students' alternative conceptions ('misconceptions'2) related to chemical and physical change, and the identified conceptions are reported in the study. Interviewees were purposively selected,
"Ten-minute semi-structured individual interviews were carried out with seven students from the experimental group and 10 students from the control group to identify students' understanding of physical and chemical changes by acquiring more information about students' unclear responses to [the post-test]. Students were selected from those who gave incorrect, partially correct and no answers to the items in the test. During the interviews, researchers asked the students to explain the reasons for their answers to the items."
Tarhan et al., 2013, p.188
I was interested to read about the alternative conceptions they had found for several reasons:
I have done research into student thinking, and have written a lot about alternative conceptions, so the general topic interests me;
More specifically, it is interesting to compare what researchers find in different educational contexts, as this gives some insight into the origins and developments of such conceptions;
In this post I am going to question whether the author's claims in their research report about some of the alternative conceptions they reported finding are convincing. First, however, I should explain the second point here.
Cultural variations in alternative conceptions
Some alternative conceptions seem fairly universal, being identified in populations all around the world. These may primarily be responses to common experiences of the natural world. An obvious example relates to Newton's first law (the law of inertia): we learn from very early experience, before we even have language to talk about our experiences, that objects that we push, throw, kick, toss, pull… soon come to a stop. They do not move off in a straight line and continue indefinitely at a constant speed.
Of course, that experience is not actually contrary to Newton's first law (as various forces are acting on the objects concerned), but it presents a consistent pattern (objects initially move off, but soon slow and stop) that becomes part of out intuitions about the world and so makes learning the scientific law seem counter-intuitive, and so more difficult to accept and apply when taught in school.
By contrast, no one has ever tested Newton's first law directly by seeing what happens under the ideal conditions under which it would apply (see 'Poincaré, inertia, and a common misconception').
Other alternative conceptions may be less universal: some may be, partially at least, due to an aspect of local cultural context (e.g. folk knowledge, local traditions), the language of instruction, the curriculum or teaching scheme, or even a particular teacher's personal way of presenting material.
So, to the extent that there are some experiences that are universal for all humans, due to commonalities in the environment (e.g., to date at least, all members of the species have been born into an environment with a virtually constant gravitational field and a nitrogen-rich atmosphere of about 1 atmosphere pressure {i.e., c.105 Pa} and about 21% oxygen content), there is a tendency for people everywhere (on earth) to develop the same alternative conceptions.
And, conversely, to the extent that people in different institutional, social, and cultural contexts have contrasting experiences, we would expect some variations in the levels of incidence of some alternative conceptions across populations.
"Some common ideas elicited from children are spread, at least in part, through informal learning in everyday "life-world" contexts. Through such processes youngsters are inducted into the beliefs of their culture. Ideas that are common in a culture will not usually contradict everyday experience, but clearly beliefs may develop and be disseminated without matching formal scientific knowledge. …
Where life-world beliefs are relevant to school science – perhaps contradicting scientific principles, perhaps apparently offering an explanation of some science taught in school; perhaps appearing to provide familiar examples of taught principles – then it is quite possible, indeed likely, that such prior beliefs will interfere with the learning of school science. …
Different common beliefs will be found among different cultural groups, and therefore it is likely that the same scientific concepts will be interpreted differently among different cultural groups as they will be interpreted through different existing conceptual frameworks."
"This suggests that studies from different contexts (e.g., different countries, different cultures, different languages of instruction, and different curriculum organisations) should be encouraged for what they can tell us about the relative importance of educational variables in encouraging, avoiding, overcoming, or redirecting various types of ideas students are known to develop."
Language of instruction may sometimes be important. Words that supposedly are translated from one language to another may actually have different nuances and associations. (In English, it is clearly an alternative conception to think the chemical elements still exist in a compound, but the meaning of the French élément chemie seems to include the 'essence' of an element that does continue into compound.)
Research in different educational contexts can in principle help unravel some of this: in principle as it does need the various researchers to detail aspects of the teaching contexts and cultural contexts from which they report as well as the student's ideas (Taber, 2012a).
Chemical and physical change
Teaching about chemical and physical change is a traditional topic in school science and chemistry courses. It is one of those dichotomies that is understandably introduced in simple terms, and so, offers a simplification that may need to be 'unlearnt' later:
[a change is] chemical change or physical change
[an element is] metal or non-metal
[a chemical bond is] ionic bonding or covalent bonding
There are some common distinctions often made to support this discrimination into two types of change:
However, a little thought suggests that such criteria are not especially useful in supporting the school student making observations, and indeed some of these criteria simply do not stand up to close examination. 2
"the distinction between chemical and physical changes is a rather messy one, with no clear criteria to help students understand the difference"
So, I was especially interested to know what Tarhan and colleagues had found.
Methodological 'small print'
In reading any study, a consideration of the findings has to be tempered by an understanding of how the data were collected and analysed. Writing-up research reports for journals can be especially challenging as referees and editors may well criticise missing details they feel should be reported, yet often journals impose word-limits on articles.
Currently (2023) this particular journal tells potential authors that "A typical paper for this journal should be between 7000 and 8000 words" which is a little more generous than some other journals. However, Tarhan and colleagues do not fully report all aspects of their study. This may in part be because they need quite a lot of space to describe the experimental teaching scheme (six different jigsaw learning activities).
Whatever the reason:
the authors do not provide a copy of the post-test which elicited the responses that were the basis of the identified alternative conceptions; and
nor do they explain how the analysis to identify conceptions was undertaken – to show how student responses were classified;
similarly, there are no quotations from the interview dialogue to illustrate how the researchers interpreted student comments .
Data analysis is the process of researchers interpreting data so they become evidence for their findings, and generally research journals expect the process to be detailed – but here the reader is simply told,
"Students' understanding of physical and chemical changes was identified according to the post-test and the individual interviews after the process."
Although the term 'misconception' is used 32 times in the paper (not counting instances in the reference list), the term is not explained in the text, presumably because it is assumed that all those working in science education know (and agree) what it means. This is not at all unusual. I once wrote about another study
"[The] qualities of misconceptions are largely assumed by the author and are implicit in what is written…It could be argued that research reports of this type suggest the reported studies may themselves be under-theorised, as rather well-defined technical procedures are used to investigate foci that are themselves only vaguely characterised, and so the technical procedures are themselves largely operationalised without explicit rationale."
Unfortunately, in Tarhan and colleagues' study there are less well-defied technical procedures in relation to how data was analysed to identify 'misconceptions', so leaving the reader with limited grounds for confidence that what are reported are worthy of being described as student conceptions – and are not just errors or guesses made on the test. Our thinking is private, and never available directly to others, and, so, can only be interpreted from the presentations we make to representour conceptions in a public (shared) space. Sometimes we mis-speak, or we mis-write (so that then our words do not accurately represent our thoughts). Sometimes our intended meanings may be misinterpreted (Taber, 2013).
Perhaps the researchers felt that this process of identifying conceptions from students' texts and utterances was unproblematic – perhaps the assignments seemed so obvious to the researchers that they did not need to exemplify and justify their analytical method. This is unfortunate. There might also be another factor here.
Lost and found in translation?
The study was carried out in Turkey. The paper is in English, and this includes the reported alternative conceptions. The study was carried out "in a public elementary school" (not an international school, for example). Although English is often taught as a foreign language in Turkish schools, the language of instruction, not unreasonably, is Turkish.
So, it seems either
the data was collected in (what, for the children, would have been) 'L2' – a second language, or
a study carried out (questions asked; answers given) in Turkish has been reported in English, translating where necessary from one language to another.
This issue is not discussed at all in the paper – there is no mention of either the Turkish or English language, nor of anything being translated.
Yet the authors are not oblivious to the significance of language issues in learning. They report how one variant of Jigsaw teaching had "been designed specifically to increase interaction among students of differing language proficiencies in bilingual classrooms" (p.186) and how the research literature reports that sometimes children's ideas reflect "the incorrect use of terms in everyday language" (p.198). However, they did not feel it was necessary to report either that
data had been collected from elementary school children in a second language, or
data had been translated for the purposes of reporting in an English language journal
It seems reasonable to assume they would have appreciated the importance of mentioning option 1, and so it seems much more likely (although readers of the study should not have to guess) the reporting in English involved translation. Yet translation is never a simple algorithmic process, but rather always a matter of interpretation (another stage in analysis), so it would be better if authors always acknowledged this – and offered some basis for readers to consider the translations made were of high quality (Taber, 2018).
It is a general principle that the research community should adopt, surely, that whenever material reported in a research paper has been translated from another language (a) this is reported and (b) evidence of the accuracy and reliability of the translation is offered (Taber, 2018).
I make this point here, as some of the alternative conceptions reported by the authors are a little mystifying, and this may(?) be because their wording has been 'degraded' (and obscured) by imperfect translation.
An alternative conception of combustion?
For example, here are two of the learning objectives from one of the learning activities:
"The students were expected to be able to:
…comment on whether the wood has similar intensive properties before and after combustion
…indicate the combustion reactions in examples of several physical and chemical changes"
Tarhan et al., 2013, p.193
The wording of the first of these examples seems to imply that when wood is burnt, the product is still…wood. That is nonsense, but possibly this is simply a mistranslation of something that made perfect sense in Turkish. (The problem is that a reader can only speculate on whether this is the case, and research reports should be precise and explicit.)
The second learning objective quoted here implies that some combustion reactions are physical changes (or, at least, combustion reactions are components of some physical changes).
Combustion reactions are a class of chemical reactions. 'Chemical reaction' is synonymous with 'chemical change'. So, there are (if you will excuse the double negative) no examples of combustion reactions that are not chemical reactions and which would be said to occur in physical changes. So, this is mystifying, as it is not at all clear what the children were actually being taught unless one assumes the researchers themselves have very serious misconceptions about the chemistry they are teaching.
If a reader actually thought that the researchers themselves held these alternative conceptions
the product of combustion of wood is still wood
some combustion reactions are (or occur as part of) physical changes
then one could have little confidence in their ability to distinguish between the scientific and alternative conceptions of others. (A reader might also ask how come the journal referees and editor did not ask for corrections here before publication – I certainly wondered about this).
There are other statements the authors make in describing the teaching which are not entirely clear (e.g., "give the order of the changes in matter during combustion reactions", p.194), and this suggests a degree of scepticism is needed in not simply accepting the reported alternative conceptions at face value. This does not negate their interest, but does undermine the paper's authority somewhat.
One of the misconceptions reported in the study is that some students thought that "there is a flame in all combustion reaction". This led me to reflect on whether I could think of any combustion reactions that did not involve a flame – and I must confess none readily came to mind. Perhaps I also have this alternative conception – but it seems a harsh judgement on elementary school learners unless they had actually been taught about combustion reactions without flames (if, indeed, there are such things).
The study reported that some 12 year olds held the 'misconception' that "there is a flame in all combustion reaction[s]".
[Image by Susanne Jutzeler, Schweiz, from Pixabay]
Failing to control variables?
Another objective was for students to "comprehend that temperature has an effect on chemical reaction rate by considering the decay of fruit at room temperature, and the change in color [colour] from green to yellow of fallen leaves in autumn" (p.193). As presented, this is somewhat obscure.
Presumably it is not meant to be a comparison between:
the rate of decay of fruit at room temperature
and
the rate of change in colour of fallen leaves in autumn
Explaining that temperature has an effect on chemical reaction rate?
Clearly, even if the change of colour of leaves takes place at a different temperature to room temperature, one cannot compare between totally different processes at different temperatures and draw any conclusions about how "temperature has an effect on chemical reaction rate" . (Presumably, 'control of variables' is taught in the Turkish science curriculum.)
So, one assumes these are two different examples…
But that does not help matters too much. The "decay of fruit at room temperature" (nor, indeed, any other process studied at a single temperature) cannot offer any indication of how "temperature has an effect on chemical reaction rate". The change of colours in leaves of deciduous trees (that usually begins before they fall) is triggered by environmental conditions such as change in day length and temperature. This is part of a very complex system involving a range of pigments, whilst water content of the leaf decreases (once the supply of water through the tree's vascular system is cut off), and it is not clear how much detail these twelve year olds were taught…but it is certainly not a simple matter of a reaction changing rate according to temperature.
Evaluating conceptions
Tarhan and colleagues report their identified alternative conceptions ('misconceptions') under a series of headings. These are reported in their table 4 (p.195). A reader certainly finds some of the entries in this table easy to interpret: they clearly seem to reflect ideas contrary to the canonical science one would expect to be reflected in the curriculum and teaching. Other statements are less obviously evidence of alternative conceptions as they do not immediately seem necessarily at odds with scientific accounts (e.g., associating combustion reactions with flames).
Other reported misconceptions are harder to evaluate. School science is in effect a set of models and representations of scientific accounts that often simplify the actual current state of scientific knowledge. Unless we know exactly what has been taught it is not entirely clear if students' ideas are credit-worthy or erroneous in the specific context of their curriculum.
Moreover, as the paper does not report the data and its analysis, but simply the outcome of the analysis, readers do not know on what basis judgements have been made to assign learners as having one of the listed misconceptions.
Changes of state are chemical changes
A few students from the lecture-based teaching condition were identified as 'having' the misconception that 'changes of state are chemical changes'. This seems a pretty serious error at the end of a teaching sequence on chemical and physical changes.
However, this raises a common issue in terms of reports of alternative conceptions – what exactly does it mean to say that a student has a conception that 'changes of state are chemical changes'? A conception is a feature of someone's thinking – but that encompasses a vast range of potential possibilities from a fleeting notion that is soon forgotten ('I wonder if s orbitals are so-called because they are spherical?') to an on-going commitment to an extensive framework of ideas that a life is lived by (Buddhism, Roman Catholicism, Liberalism, Hedonism, Marxism…).
A person's conceptions can vary along a range of characteristics (Figure from Taber, 2014)
The statement that 'Changes of state are chemical changes' is unlikely to be the basis of anyone's personal creed. It could simply be a confusion of terms. Perhaps a student had a decent understanding of the essential distinction between chemical and physical changes but got the terms mixed up (or was thinking that 'changes of state' meant 'chemical reaction'). That is certainty a serious error that needs correcting, but in terms of understanding of the science, would seem to be less worrying than a deeper conceptual problem.
In their commentary, the authors note of these children:
"They thought that if ice was heated up water formed, and if water was heated steam formed, so new matter was formed and chemical changes occurred".
Tarhan et al., 2013, p.197
It is not clear if this was an explanation the learners gave for thinking "changes of state are chemical changes", or whether "changes of state are chemical changes" was the researchers' gloss on children commenting that "if ice was heated up water formed, and if water was heated steam formed, so new matter was formed and chemical changes occurred".
That a range of students are said to have precisely the same train of thought leads a reader (or, at least, certainly one with experience of undertaking research of this kind) to ask if these are open-ended responses produced by the children, or the selection by the children of one of a number of options offered by the researchers (as pointed out above, the data analysis is not discussed in detail in the paper). That makes a difference in how much weight we might give to the prevalence of the response (putting a tick by the most likely looking option requires less commitment to, and appreciation of, an idea than setting it out yourself in your own personally composed text), illustrating why it is important that research journals should require researchers to give full accounts of their instrumentation and analysis.
Because density of matter changes during changes of state, its identity also changes, and so it is a chemical change
Thirteen of the children (all in the lecture-based teaching condition) were considered to have the conception "Because density of matter changes during changes of state, its identity also changes, and so it is a chemical change". This is clearly a much more specific conception (than 'changes of state are chemical changes') which can be analysed into three components:
a change of state is a chemical change, AND
we know this because such changes involve a change in identity, AND
we know that because a change of state leads to a change in density
Terhan and colleagues claim this conception was "first determined in this study" (p.195).
The specificity is intriguing here – if so many students explicitly and individually built this argument for themselves then this is an especially interesting finding. Unfortunately, the paper does not give enough detail of the methodology for a reader to know if this was the case. Again, if students were just agreeing with an argument offered as an option on the assessment instrument then it is of note, but less significant (as in such cases students might agree with the statement simply because one component resonated – or they may even be guessing rather than leaving an item unanswered). Again this does not completely negate the finding, but it leaves its status very unclear.
Taken together these first two claimed results seem inconsistent – as at least 13 students seem to think "Changes of state are chemical changes". That is, all those who thought that "Because density of matter changes during changes of state, its identity also changes, and so it is a chemical change" would seem to have thought that "Changes of state are chemical changes" (see the Venn diagram below). Yet, we are also told that only five students held the less specific and seemingly subsuming conception "changes of state are chemical changes".
If 13 students think that changes of state are chemical changes because a change of density implies a change of identity; what does it mean that only 5 students think that changes of state are chemical changes?
This looks like an error, but perhaps is just a lack of sufficient detail to make the findings clear. Alternatively, perhaps this indicates some failure in translating material accurately into English.
The changes in the pure matters are physical changes
Six children in the lecture-based teaching condition and one in the jigsaw learning condition were reported as holding the conception that "The changes in the pure matters are physical changes". The authors do not explain what they mean here by "pure matters" (sic, presumably 'matter'?). The only place this term is used in the paper is in relation to this conception (p.195, p.197).
The only other reference to 'pure' was in one of the learning objectives for the teaching:
explain the changes of state of water depending on temperature and pressure; give various examples for other pure substances (p.191)
If "pure matter" means a pure sample of a substance, then changes in pure substances are all physical – by definition a chemical changes leads to a different substance/different substances. That would explain why this conception was "first determined [as a misconception] in this study", p.195, as it is not actually a misconception)". So, it does not seem clear precisely why the researchers feel these children have got something wrong here. Again, perhaps this is a failure of translation rather than a failure in the original study?
Changes in shape?
Tarhan and colleagues report two conceptions under the subheading of 'changes in shape'. They seem to be thinking here more of grain size than shape as such. (Another translation issue?) One reported misconception is that if cube sugar is granulated, sugar particles become small [smaller?].
Is it really a misconception to think that "If cube sugar is granulated, sugar particles become small"?
(Image by Bruno /Germany from Pixabay)
Tarhan and colleagues reported that two children in the experimental condition, and 13 in the control condition thought that "If cube sugar is granulated, sugar particles become small". Sugar cubes are made of granules of sugar weakly joined together – they can easily be crumbled into the separate grains. The grains are clearly smaller than the cubes. So, what is important here is what is meant/understood* by the children by the term 'particles'.
(* If this phrasing was produced by the children, then we want to know what they meant by it. If, however, the children were agreeing with a phrase presented to them by researchers, then we wish to know how they understood it.)
If this means quanticle level particles, molecules, then it is clearly an alternative conception – each grain contain vast numbers of molecules, and the molecules are unchanged by the breaking up the cubes. If, however, particles here refers to the cube and grains**, then it is a fair reflection of what happens: one quite large particle of sugar is broken up into many much smaller particles. The ambiguity of the (English) word 'particles' in such contexts is well recognised.
(** That is, if the children used the word 'particles' – did they mean the cubes/grains as particles of sugar? If however the phrasing was produced by the researchers and presented to the children, and if the researchers meant 'particles' to mean 'molecules'; did the children appreciate that intention, or did they understand'particles' to refer to the cubes and grains?)
However, as no detail is given on the actual data collected (e.g., is this the children's own words; was this based on an open response?), and how it was analysed (and, as I suspect this all occurred in Turkish) the reader has no way to check on this interpretation of the data.
What kind of change is dissolving?
Tarhan and colleagues report a number of 'misconceptions' under the heading of 'molecular solubility'. Two of these are:
"The solvation processes are always chemical changes"
"The solvation processes are always physical changes"
This reflects a problem of teaching about physical and chemical changes. Dissolving is normally seen as a physical change: there is no new chemical substance formed and dissolving is usually fairly readily reversed. However, as bonds are broken and formed it also has some resemblance to chemical change.2
In dissolving common salt in water, strong ionic bonds are disrupted and the ions are strongly solvated. Yet the usual convention is still to consider this a physical change – the original substance, the salt, can be readily recovered by evaporation of the solvent. A solution is considered a kind of mixture. In any case, as Tarhan and colleagues refer to 'molecular' solubility (strictly solubility refers to substances, not molecules, but still) they were, presumably, only dealing with examples of the dissolving of substances with discrete molecules.
Taking together these two conceptions, it seems that Tarhan and colleagues think that dissolving is sometimes a physical change, and sometimes a chemical change. Presumably they have some criterion or criteria to distinguish those examples of dissolving they consider physical changes from those they consider chemical changes. A reader can only speculate how a learner observing some solute dissolve in a solvent is expected to distinguish these cases. The researchers do not explain what was taught to the students, so it is difficult to appreciate quite what the students supposedly got wrong here.
Sugar is invisible in the water, because new matter is formed
The idea that learners think that new matter is formed on dissolving would indeed be an alternative conception. The canonical view is that new matter is only formed in very high energy processes – such as in the big bang. In both chemical and physical processes studied in the school laboratory there may be transformations of matter, but no new matter.
This seems a rather extreme 'misconception' for the learners to hold. However, a reader might wonder if the students actually suggested that a new substance was formed, and this has been mistranslated. (The Turkish word 'madde' seems to mean either matter or substance.) If these students thought that a new type of substance was formed then this would be an alternative conception (and it would be interesting to know why this led to sugar being invisible – unless they were simply arguing that different appearance implied different substance).
While sugar is dissolving in the water, water damages the structure of sugar and sugar splits off
Whether this is a genuine alternative conception or just imprecise use of language is not clear. It seems reasonable to suggest that while sugar is dissolving in the water, the process breaks up the structure of solid sugar and sugar molecules split off – so some more detail would be useful here. Again, if there has been translation from Turkish this may have lost some of the nuance of the original phrasing through translation into English.
The phrasing reflects an alternative conception that in chemical reactions one reactant is an active agent (here the water doing the damaging) and the other the patient, that is passive and acted upon (here the sugar being damaged) – rather than seeing the reaction as an interaction between two species (Taber & García Franco, 2010) – but there is no suggestion in their paper that this is the issue Tarhan and colleagues are highlighting here.
When sugar dissolves in water, it reacts with water and disappears from sight
If the children thought that dissolving was a chemical reaction then this is an alternative conception – the sugar does indeed disappear from sight, but there has been no reaction.
Again, we might ask if this was actually a misunderstanding (misconception), or imprecise use of language. The sugar does 'react' with the water in the everyday sense of 'reaction'. But this is not a chemical reaction, so this terminology should be avoided in this context.
Even in science, 'reaction' means something different in chemistry and physics: in the sense of Newtonian physics, during dissolving, when a water molecule attracts a sugar molecule {'action')'} there will be an equal and oppositely directed reaction as the sugar molecule attracts the water molecule. This is Newton's third law, which applies to quanticles as much as to planets. If a water molecule and a sugar molecule collide, the force applied by the sugar molecule on the water molecule is equal to the force applied by the water molecule on the sugar molecule.
a use of the everyday term 'reaction' in a context where this should be avoided as it can be misunderstood
These are somewhat different problems for a teacher to address.
Molecules split off in physical changes and atoms split off in chemical changes
Ten of the children are said to have demonstrated the 'misconception' that molecules split off in physical changes and atoms split off in chemical changes. The authors claim that this misconception has not been reported in previous studies. But is this really a misconception? It may be a simplistic, and imprecise, statement – but I think when I was teaching youngsters of this age I would have been happy to find they have this notion – which at least seems to reflect an ability to imagine and visualise processes at the molecular level.
In dissolving or melting/boiling of simple molecular substances, molecules do indeed 'split off' in a sense, and in at least some chemical changes we can posit mechanisms that, in simple terms at least, involve atoms 'splitting off' from molecules.
So, again, this is another example of how this study is tantalising, without being very informative. The reader is not clear in what sense this is viewed as wrong, or how the conception was detected. (Again, for ten different students to specifically think that 'molecules split off in physical changes and atoms split off in chemical changes' makes one wonder if they volunteered this, or have simply agreed with the statement when having it presented to them).
The researchers do not detail their data collection and analysis instruments and protocols in sufficient detail for a readers to appreciate what they mean by their results. In particular, what it means to have a misconception – e.g., to give a definitive statement in an interview, or just to select some response on a test as the answer that looked most promising at the time. Clearly we give much more weight to a notion that a learner presents in their own words as an explanation for some phenomenon, than the selection of one option from a menu of statements presented to them that comes with no indication of their confidence in the selection made.
Of particular concern: either the children were asked questions in a second language that they may not have been sufficiently fluent in to fully understand questions or compose clear responses; or none of the misconceptions reported are presented in their original form and they have all been translated by someone (unspecified) of uncertain ability as a translator. (A suitably qualified translator would need to have high competence in both languages and a strong familiarity with the subject matter being translated.)
In the circumstances, Tarhan and colleagues' reported misconceptions are little more than intriguing. In science, the outcome of a study is only informative in the context of understanding exactly how the data were obtained, and how they have been processed. Without that, readers are asked to take a researcher's conclusions on faith, rather than be persuaded of them by a logical chain of argument.
p.s. For anyone who did not know, but wondered: s orbitals are not so-called because they are spherical: the designation derives from a label ('sharp') that was applied to some lines in atomic spectra.
1 To my reading, the publication title 'Research in Science and Technological Education' seems to suggest the journal has two distinct and somewhat disconnected foci, that is:
Research in ( Science ) and ( Technological Education )
And it would be better (that is, most consistently) titled as
Research in Science and Technology Education
{Research in ( Science and Technology ) Education}
or
Research in Scientific and Technological Education
{Research in ( Scientific and Technological ) Education}
but, hey, I know I am pedantic.
2 The table (Table 1.2 in the source) was followed by the following text:
"The first criterion listed is the most fundamental and is generally clear cut as long as the substances present before and after the change are known. If a new substance has been produced, it will almost certainly have different melting and boiling temperatures than the original substance.
The other [criteria] are much more dubious. Some chemical changes involve a great deal of energy being released, such as the example of burning magnesium in air, or even require a considerable energy input, such as the example of the electrolysis of water. However, other reactions may not obviously involve large energy transfers, for example when the enthalpy and entropy changes more or less cancel each other out…. The rusting of iron is a chemical reaction, but usually occurs so slowly that it is not apparent whether the process involves much energy transfer ….
Generally speaking, physical changes are more readily reversible than chemical changes. However, again this is not a very definitive criterion. The idea that chemical reactions tend to either 'go' or not is a useful approximation, but there are many examples of reactions that can be readily reversed…. In principle, all reactions involve equilibria of forward and reverse reactions, and can be reversed by changing the conditions sufficiently. When hydrogen and oxygen are exploded, it takes a pedant to claim that there is also a process of water molecules being converted into oxygen and hydrogen molecules as the reaction proceeds, which means the reaction will continue for ever. Technically such a claim may be true, but for all practical purposes the explosion reflects a reaction that very quickly goes to completion.
One technique that can be used to separate iodine from sand is to warm the mixture gently in an evaporating basin, over which is placed an upturned beaker or funnel. The iodine will sublime – turn to vapour – before recondensing on the cold glass, separated from the sand. The same technique may be used if ammonium chloride is mixed with the sand. In both cases the separation is achieved because sand (which has a high melting temperature) is mixed with another substance in the solid state that is readily changed into a vapour by warming, and then readily recovered as a solid sample when the vapour is in contact with a colder surface. There are then reversible changes involved in both cases:
solid iodine ➝ iodine vapour
ammonium chloride ➝ ammonia + hydrogen chloride
In the first case, the process involves only changes of state: evaporation and condensation – collectively called sublimation. However the second case involves one substance (a salt) changing to two other substances. To a student seeing these changes demonstrated, there would be little basis to infer one is (usually considered as) a chemical change, but not the other. …
The final criterion in Table 1.2 concerns whether bonds are broken and made during a change, and this can only be meaningful for students once they have learnt about particle models of the submicroscopic structure of matter… In a chemical change, there will be the breaking of bonds that hold together the reactants and the formation of new bonds in the products. However, we have to be careful here what we mean by 'bond' …
When ice melts and water boils, 'intermolecular' forces between molecules are disrupted and this includes the breaking of hydrogen 'bonds'. However, when people talk about bond breaking in the context of chemical and physical changes, they tend to mean strong chemical bonds such as covalent, ionic and metallic bonds…
Yet even this is not clear cut. When metals evaporate or are boiled, metallic bonds are broken, although the vapour is not normally considered a different substance. When elements such as carbon and phosphorus undergo phase changes relating to allotropy, there is breaking, and forming, of bonds, which might suggest these changes are chemical and that the different forms of the same elements should be considered different substances. …
A particularly tricky case occurs when we dissolve materials to form solutions, especially materials with ionic bonding…. Dissolving tends to involve small energy changes, and to be readily reversible, and is generally considered a physical change. However, to dissolve an ionic compound such as sodium chloride (table salt), the strong ionic bonds between the sodium and chloride ions have to be overcome (and new bonds must form between the ions and solvent molecules). This would seem to suggest that dissolving can be a chemical change according to the criterion of bond breaking and formation (Table 1.2)."
Fact is said to be stranger than (science) fiction
Regular viewers of Star Trek may be under the impression that it is dangerous to enter the neutral zone between the territories claimed by the United Federation of Planets and that of the Romulan Empire in case any incursion results in an attack by a Romulan Bird of Prey.
"All the more remarkable is the observation that a neutral zone insinuates itself between the nest and the hunting ground of many raptors, a zone in which they seize no prey at all. Ornithologists must be correct in their assumption that this organisation of the environment was made by Nature in order to keep the raptors from seizing their own young. If, as they say, the nestling becomes a branchling and spends its days hopping from branch to branch near the parental nest, it would easily be in danger of being seized by mistake by its own parents. In this way, it can spend its days free of danger in the neutral zone of the protected area. The protected area is sought out by many songbirds as a nesting and incubation site where they can raise their young free of danger under the protection of the big predator."
Uexküll, 1934/2010
This is a very vivid presentation, but is phrased in a manner I thought deserved a little interrogation. It should, however, be pointed out that this extract is from the English edition of a book translated from the original German text (which itself was originally published almost a century ago).
A text with two authors?
Translation is a process of converting a text from one natural language to another, but every language is somewhat unique regarding its range of words and word meanings. That is, words that are often considered equivalent in different language may have somewhat different ranges of application in those languages, and different nuances. Sometimes there is no precise translation for a word, and a single word in one language may have several near-equivalents in another (Taber, 2018). Translation therefore involves interpretation and creative choices.
So, translation is a skilled art form, and not simply something that can be done well by algorithmically applying suggestions in a bilingual dictionary. A good translation of an academic text not only requires someone fluent in both languages, but also someone having a sufficient understanding of the topic to translate in the best way to convey the intended meaning rather than simply using the most directly equivalent words. A sequence of the most equivalent individual words may not give the best translation of a sentence, and indeed when translating idioms may lead to a translation with no obvious meaning in the target language. It is worth bearing in mind that any translated text has (in effect) two authors, and reflects choices made by the translator as well as the original author.
I am certainly not suggesting there is anything wrong with the translation of Uexküll's text, but it should be born in mind I am commenting on the English language versionof the text.
A neutral zone insinuates itself
No it does not.
The language here is surely metaphorical, as it implies a deliberate action by the neutral zone. This seems to anthropomorphise the zone as if it is a human-like actor.
The zone is a space. Moreover, it is not a space that is in any way discontinuous with the other space surrounding it – it is a human conception of a region of space with imagined boundaries. The zone is not a sentient agent, so it can not insinuate itself.
Ornithologists must be correct
Science develops theoretical knowledge which is tested against empirical evidence, but is always (strictly) provisional in that it should be open to revisiting in the light of further evidence. Claims made in scientific discourse should therefore be suitable tentative. Perhaps
ornithologists seem to be correct in suggesting…, or
it seems likely that ornithologists were correct when they suggested…or even
at present our best understanding reflects the suggestions made by ornithologists that...
Yet a statement that ornithologists must be correct implies a level of certainty and absoluteness that seems inconsistent with a scientific claim.
This phrasing seems to personify Nature as if 'she' is a person. Moreover, this (…in order to…) suggests a purpose in nature. This kind of teleological claim is often considered inappropriate in science as it suggests natural events occur according to some pre-existing plan rather than unfolding according to natural laws. 1 If we consider something happens to achieve a purpose we seem to not need to look for a mechanism in terms of (for example) forces (or entropy or natural selection or…).
We can understand that it would decrease the biological fitness of a raptor to indiscriminately treat its own offspring as potential food. There are situations when animals do eat their young, but clearly any species that's members committed considerable resources to raising a small number of young (e.g., nest building, egg incubation) but were also regular consumers of those young would be at a disadvantage when it came to its long-term survival.
So, in terms of what increases a species' fitness, avoiding eating your own children would help. If seeking a good 'strategy' to have descendants, then, eating offspring would be a 'mistake'. But the scientific account is not that species, or individual members of a species, seek to deliberately adopt a strategy to have generations of descendants: rather behaviour that tends to lead to descendants is self-selecting.
Just because humans can reflect upon 'our children's children's, children', we cannot assume that other species even have the vaguest notions of descendants. (And the state of the world – pollution, deforestation, habitat destruction, nuclear arsenals, soil degradation, unsustainable use of resources, etcetera – stronglysuggests that even humans who can conceptualise and potentially care about their descendants have real trouble making that the basis for rational action.)
Even members of the very rare species capable of conceptualising a future for their offspring struggle to develop strategies taking the well-being of future generations into account. (Image: cover art for 'To our children's children's children' {The Moody Blues}).
Natural selection is sometimes seen as merely a tautology as it seems to be a theory that explains the flourishing of some species (and not others) in terms that they have the qualities to flourish! But this is to examine the wrong level of explanation. Natural selection explains in general terms why it is that in a particular environment competing species will tend to survive and leave offspring to different extents. (Then within that general framework, specific arguments have to be made about why particular features or behaviours contribute to differential fitness in that ecological context.)
Particular evolved behaviours may be labelled as 'strategies' by analogy with human strategies, but this is purely a metaphor: the animal is following instincts, or sometimes learned behaviours, but is not generally following a consciously considered plan intended to lead to some desired outcome in the longer term.
But a reader is likely to read about a nestling being "in danger of being seized by mistake by its own parents" as the birds themselves making a mistake – which implies they have a deliberate plan to catch food, while excluding their own offspring from the food category, and so intended to avoid treating their offspring as prey. That is, it is implied that birds of prey are looking to avoid eating their own, but get it wrong.
Yet, surely, birds are behaving instinctively, and not conceptualising their hunting as a means of acquiring nutrition, where they should discriminate between admissible prey and young relatives. Again this seems to be anthropomorphismas it treats non-human animals as if their have mental experiences and thought processes akin to humans: "I did not mean to eat my child, I just failed to recognise her, and so made a mistake".
The protected area is sought out
Similarly, the songbirds also behave instinctively. They surely do not 'seek out' the 'protected' area around the nest of a bird of prey. There must be a sense in which they 'learn' (over many generations, perhaps) that they need not fear the raptors when they are near their own nests but it seems unlikely a songbird conceptualises any of this in a way that allows them to deliberately (that is, with deliberation) seek out the neutral zone.
In terms of natural selection, a songbird that has no fear of raptors and so does not seek to avoid or hide or flee from them would likely be at a disadvantage, and so tend to leave less offspring. Similarly, a songbird that usually avoided birds of prey, but nested in the neutral zone, would have a fitness advantage if other predators (small cats say) kept clear of the area. The bird would not have to think "hey, I know raptors are generally a hazard, but I'll be okay here as I'm close enough to be in the zone where they do not hunt", as long as the behaviour was heritable (and there was initially variation in the extent to which individuals behaved that way) – as natural selection would automatically lead to it becoming common behaviour.
(In principle, the bird could be responding to some cue in the environment that was a reliable but indirect indicator they were near a raptor nesting site. For example, perhaps building a nest very close to a location where there is a regular depositing of small bones on the ground gives an advantage, so this behaviour increases fitness and so is 'selected'.)
Under the protection of the big predator
Why are the songbirds under the protection of the raptors? Perhaps because other potential predators do not come into the neutral zone as they are vulnerable when approaching this area, even if they would be safe once inside. Again, if this is so, it surely does not reflect a conscious conceptualisation of the neutral zone.
For example, a cat that preys on small birds would experience a different 'umwelt' from the bird. A small songbird with a nest where it has young experiences the surrounding space differently to a cat (already a larger animal so experiencing the world at a different scale) that ranges over a substantial territory. Perhaps the songbird perceives the neutral zone as a distinct space, whereas to the cat it is simply an undistinguished part of a wider area where the raptors are regularly seen.
Or, perhaps, for the smaller predator, the area around the neutral zone offers too little cover to risk venturing into the zone. (Again, this does not mean a conscious thinking process along the lines "I'd be safe once I was over there, but I'm not sure I'd make it there as I could easily be seen moving between here and there", but could just be an inherited tendency to keep under cover.)
The birds of prey themselves will not take the songbirds, so the smaller birds are protected from them in the zone, but if this is simply an evolved mechanism that prevents accidental 'infanticide' this can hardly be considered as other birds being under the protection ofthe birds of prey. Perhaps the birds of prey do scare away other predators – but, if so, this is in no sense a desired outcome of a deliberate policy adopted by the birds of prey because they want to protect their more vulnerable neighbours.
One could understand how the birds of prey might hypothetically have evolved behaviour of not preying on smaller birds (which might include their own offspring) near their nest, but would still attack smaller predators that might threaten their own chicks. In that scenario 2, the birds of prey might have indeed protected nearby songbirds from potential predators (even if only incidentally), but this does not apply if, as Uexküll suggests, "they seize no prey at all" in the neutral zone.
Again the, 'under the protection of the big predator' seems to anthropomorphise the situation and treat the birds of prey as if they are acting deliberately to protect songbirds, and so this phrasing needs to be understood metaphorically.
Does language matter?
Uexküll's phrasing offers an engaging narrative which aids in the communication of the idea of the neutral zone to his readers. (He is skilled in making the unfamiliar familiar.) It is easier to understand an abstract idea if it seems to reflect a clear purpose or it can be understood in terms of human ways of thinking and acting, for example:
it is important to keep your children safe
it is good to look out for your neighbours
But we know that science learners readily tend to accept explanations that are teleological and/or anthropomorphic, and that sometimes (at least) this acts as an impediment to learning the scientific accounts based on natural principles and mechanisms.
Therefore it is useful for science teachers in particular to be alert to such language so they can at least check that learners are seeing beyond the metaphor and not mistaking a good story for a scientific account.
Uexküll, J. v. (1934/2010). A Foray into the Worlds of Animals (J. D. O'Neil, Trans.). In A Foray into the Worlds of Animals; with, A Theory of Meaning (pp. 39-135). University of Minnesota Press.
Notes:
1 Many people, including some scientists, do believe the world is unfolding according to a pre-ordained plan or scheme. This would normally be considered a matter of religious faith or at least a metaphysicalcommitment.
The usual stance taken in science ('methodological naturalism'), however, is that scientific explanations must be based on scientific principles, concepts, laws, theories, etcetera, and must not call upon any supernatural causes or explanations. This need not exclude a religious faith in some creator with a plan for the world, as long as the creator is seen to have set up the world to unfold through natural laws and mechanisms. That is, faith-based and scientific accounts and explanations may be considered to work at different levels and to be complementary.
2 That this does not seem to be the case might reflect how a flying bird perceives prey – if it has simply evolved to swoop upon and take any object in a certain size range {that we might explain as small enough to be taken, but not so small as not to repay the effort} that matches a certain class of movement pattern {that we might interpret as moving under its own direction and so being animate} then the option of avoiding smaller birds but taking other prey would not be available.
After all, studies show parent birds will try and feed the most simple representations of a hatchling's open beak – suggesting they do not perceive the difference between their own children and crude models of an open bird mouth.
The general form of a chick's open mouth (as shown by these hatchlings) is enough to trigger feeding behaviour in adult birds. (Image by Tania Van den Berghen from Pixabay )
Uexküll himself reported that,
"…a very young wild duck was brought to me; it followed me every step. I had the impression that it was my boots that attracted it so, since it also ran occasionally after a black dachshund. I concluded from this that a black moving object was sufficient to replace the image of its mother…"
Uexküll, 1934/2010
(A year later, Lorentz would publish his classic work on imprinting which reported detailed studies of the same phenomenon.)
My library is in desperate need of some sorting and tidying, but I have a tendency, when entering in there and picking up a book I've not looked at for while, to dip into it rather than get organising.
So it was that I found myself re-reading the Introduction to Richard Muller's (1988) book 'Nemesis: The Death Star'. I presumably do not need to describe the book as it is so widely read (😉 see below)1, but the Introduction was by Muller's colleague and former research supervisor Luis Alverez – a Nobel Prize winning physicist. He died the same year that Nemesis was published, so this was probably one of his last pieces of writing about science.
A claim that cannot be taken at face vlaue
In the introduction, Alverez suggests that,
"I am convinced that every student of physics will read and reread Nemesis several times, learning important lessons on each occasion, as well as having a wonderful time."
Alverez, 1988, p.xi
Now I struggle with this kind of claim.
Richard Muller's book 'Nemesis The Death Star' – has this been read and reread by every student of physics since 1988?
I have admitted here before to being rather pedantic, and although it's never been diagnosed as being on the autism spectrum, I recognise I do share some of the common traits – including a tendency to focus on literal meanings. (Perhaps that explains my regular exploration of scientific metaphors and the like on this site).
Clearly, Alverez thinks very highly of Muller, and the work reported is related to some of his own research, so there might be some quite understandable personal bias here. I am also prepared to be charitable, and read 'every student of physics' to only refer to those majoring in physics at university level rather than anyone taking a physics course.
Even so, I find this an extraordinary thing to write.
Now, I was recently asked to write something about a book I had been sent in manuscript and was quite happy to suggest that the book (on a critical but generally under-examined theme) should be required reading for all future science educators. But that is surely different: the kind of difference to be drawn between the claims:
all good citizens should pay their due taxes
all citizens do pay their due taxes
Alverez was not only suggesting that he thought all physics students would benefit from the book, but was apparently making a prediction, moreover a 'confident' prediction, that all future physics students would read the book (at least twice!) and enjoy it. The likelihood of that must have surely seemed infinitesimally small!
Had this been part of the cover blurb, I might have suspected the publisher had taken liberties with the text (which should not surprise me as publishers now seem to regularly issue contracts asking authors for the right to change their scholarly text in any way that suits them). I had wondered if that had happened, for example, when I read on the cover of a book on evolution the author's claim that today everyone accepts Darwin's theory.2 But Alverez was not writing an endorsement, but a part of the book itself. (This was not even a Foreword – but the actual Introduction to the book.)
I can only understand Alverez's claim if I understand it as a piece of rhetoric, indeed hyperbole – surely the author could not possibly really think that henceforth every physics student was going to read and reread this book about one specialised programme of research (and which was very unlikely to be directly relevant to the assignments and examinations that would given them course credit) no mater how interesting it might be? Surely, rather, he was just communicating via rhetoric that the book was so worthy of attention that in his view it would justify such a broad readership.
What's wrong with rhetoric?
I see this as an issue worth raising because (a) the statement is a knowledge claim and (b) the claim was made by a scientist in the context of part of a book reporting scientific work.
Yet it is in the nature of scientific knowledge that it is theoretical, and, strictly, provisional (always open to be revisited in the light of new evidence or ways of interpreting evidence) – and therefore scientific knowledge claims should reflect this, and not be absolute.
This is one way that some accounts of science that appear in the news and other media distort the nature of science (and usually the original reports of that science as presented in research journals) by suggesting scientists have made discoveries that definitively prove some idea or other and reflect certain, absolute, knowledge
Alverez's claim is absolute: all physics students WILL read and re-read this book.
I am not suggesting that there is no place for rhetoric in science. Scientific claims are presented in formal research reports which are organised to make an argument for the claims being presented. They are rhetorical.
But, even if scientific claims are structured rhetorically in order to make a case, they still need to be measured, and honest, and – if they are to be considered scientific – suitably provisional.
This was perhaps [sic] exemplified when Crick and Watson, reporting what was arguably [sic] one of the most important scientific discoveries of the twentieth, if not all, centuries, pointed out that
"It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material."
Watson & Crick, 1953
They did not suggest that
"our model of D.N.A. structure definitely provides the mechanism by which genetic material IS copied and is without doubt the basis of heredity".
Counterfactual: what Crick and Watson did not publish in Nature
So, rhetoric is important in science – scientists need the ability to present a best case for the argument being made so that other scientists can readily appreciate the logic of, and strength of, some new claim. However, hyperbole involves making such extreme exaggerations that they are not expected to be taken literally, and surely has no place in scientific writing. When a scientist make an absolutist claim (e.g., "every student of physics will read and reread Nemesis several times [and have a] wonderful time") other scientists know this cannot be seen as an authentic scientific claim, and so are likely to simply disregard it as something which cannot be interpreted sensibly within the context of scientific discourse.
Sources cited
Alvarez, L. W. (1988). Introduction. In Nemesis: The Death Star. The story of a scientific revolution (pp. xi-xiii). Guild Publishing.
Watson, J. D., & Crick, F. H. C. (1953). Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid. Nature, 171(4356), 737-738.
Muller, R. (1988). Nemesis: The Death Star. The story of a scientific revolution. Guild Publishing.
Eldredge, N. (1995). Reinventing Darwin: The great evolutionary debate. Weidenfeld and Nicolson.
Note:
1 Just in case anyone has not read the book, it describes a theory that the earth is subject to regular mass extinction events due to the effect of a planet (Nemesis) with such a large and eccentric orbit that it only comes near the sun once every 26 million years. The publisher tells readers that
"…the Nemesis hypothesis has established itself as the only viable scientific theory to explain a bewildering variety of phenomena in fields ranging from geology to astronomy to palaeontology…"
but then the editor responsible for this claim has presumably NOT won a physics Nobel prize.
(Image by Bela Geletneky from Pixabay)
2 The back cover of 'Reinventing Darwin' (Eldredge, 1995) tells potential readers that,
"No one doubts that Darwin's theory of Evolution by Natural Selection is correct."
No matter how much one recognises natural selection and Neodarwinism as the consensus view, the present paradigm, in the scientific community, it is difficult to believe that any person on earth who has taken any interest in the matter is not aware that there are large numbers of people (albeit, only a small proportion of practising scientists) who not only 'doubt' Darwin was correct but, in many cases, are strongly committed to the idea that he was completely wrong!
An ancient iron column: Did "a very thin layer of phosphorus formed, between the rust and the fresh metal and basically stop… it from rustingany more"
What do you need to build a skyscraper?
I was listening to a podcast from the Royal Institution (where Humphrey Davy and Michael Faraday were based). I must confess I had downloaded the 'Recipe for a Skyscraper' episode some time ago but it had been passed over for other titles.
My mistake. In this talk "structural engineer Roma Agrawal delves into the history of the materials that enable immense construction and the developments that have made our structures what they are today. All while noting the accomplishments of key visionary engineers of the past". This proved to be an engaging and fascinating talk.
A 'mega badass engineer'
On her website, Roma Agrawal , "a structural engineer, author and broadcaster, with a physics degree" describes herself as a "mega badass engineer". She is not above being a little mischievous.
The crumbly ages
For example, she has her own take on what historians used to call the 'dark ages', 1
"So, oddly enough, once the Roman empire fell, the use of concrete basically ended for nearly a thousand years, so that we call it the dark ages, or the crumbly ages as I like to call it, because they went back to using slightly older [construction materials], you know, mud and brick and things like that."
Roma Agrawal talking at the Royal Institution
But while the Romans may have championed the use of concrete, the Indians were outperforming them in the production of high quality iron: "The Romans actually used to import Indian steel at the time and they never knew how to make it because that secret was closely guarded…"
Iron is too reactive to be found 'native' but has to be produced by roasting its ores (that contain compounds of iron) with materials that will reduce the iron compounds to iron, and produce, as a by-product, slag – a complex mixtures of substances. The iron produced will contain some slag mixed into the metal unless this is carefully removed. 2
The Delhi column
As an example of the Indian expertise, Roma Agrawal referred to an old iron column near Delhi which "had not rusted" despite having been erected 1500 years ago.3 The column had originally been a stand for a statue of Garuda, the divine winged creature/demigod who acted as the vehicle for Vishnu. Garuda seems to have flown, but the iron column remains.
The (not quite 4) 'rustless wonder' (Srinivasan & Ranganathan, 2013): the Qtub Iron Pillar
Lord Vishnu on his mount Garuda (wood carving). It is thought the iron pillar near Delhi once supported a statue of Garuda.
(Image by waradet from Pixabay)
Iron is the main constituent of alloys known as steels, and by mixing other elements (principally, but not only, carbon) with iron it is possible to create steels with various properties, including corrosion resistance. 2 But iron itself readily rusts. The rust formed when iron corrodes is permeable and crumbly, exposing the unreacted metal beneath, which in turn forms rust that again fails to protect the iron beneath it. So, over time, a piece of iron can simply 'rust away' as the reacted material will simply fall off, or be eroded by weather.
Yet this iron column, erected around the time of the final collapse of the Roman Empire, seems to have survived throughout 'the crumbly ages' and through to the present day. Although, it is not that it never started rusting 4, but rather,
"it did initially rust, but then because of the climate in Delhi, the phosphorus, a very thin layer of phosphorus formed, between the rust and the fresh metal and basically stopped it from rusting any more…"
Roma Agrawal talking at the Royal Institution
Corrosion (as with tarnishing) is a generic term. Corrosion leads to structural damage to metal objects (whereas tarnishing is a surface effect).
Rusting is specific to iron as it refers to the material produced when iron corrodes – i.e., rust.
Unreactive phosphorus?: An alternative conception
Roma Agrawal's claim seems incredible to a chemist or science teacher because phsophorus is a very reactive element, and a very reactive element does not seem a good choice of material to protect iron from reacting! Even if the phosphorus did not itself react with the iron and so corrode it, it would soon react with air. In the laboratory, some forms of phosphorus can burst into flames spontaneously, suggesting it is very unlikely to remain intact very long exposed to the elements in India. Certainly not many centuries.
Sacrificial elements
Now, sometimes a more valuable metal is protected by connecting it physically to a more reactive but less valuable metal which preferentially corrodes. As the metals are in electrical contact, the one that loses electrons and releases cations more readily reacts first. The metal allowed to corrode is called a 'sacrificial' metal. For example, bars of sacrificial metal may be dangled from piers or oil rigs to protect the structural metal. The sacrificial metal will slowly 'dissolve' away into the sea 5 – but not that slowly that it would not need replacing for over a millennium. In any case, phosphorus is a non-metal, where the sacrificial element of the pair needs to be the more electropositive. So, there is no helpful explanation there.
Alumina – when tarnishing prevents corrosion
Aluminium is a more reactive metal than iron, yet does not readily undergo substantive corrosion. This is because the surface of an aluminium object readily reacts with oxygen from the air to form a layer of aluminium oxide (alumina). This then protects the aluminium because the alumina formed is a fairly inert substance (unlike the highly reactive phosphorus), and it forms an impermeable layer (preventing oxygen from the air reaching the metal beneath).
Any layer that were to form on iron protect it from rusting also needs to be impermeable and relatively inert. Unlike reactive phosphorus.
Phosphorus would not protect iron
Phosphorus is a fire hazard that burns to produce toxic fumes. In the laboratory, the direct reaction of iron and phosphorus usually requires heating to initiate reaction. Without active heating, the rate of reaction would be too low for a useful laboratory process. However, a very low rate of reaction would not prevent reaction over the centuries since the iron column was erected.
Even if phosphorus was able to form a layer that coated over the iron, using it as a means to prevent corrosion would be like fireproofing a wooden building by coating it with petroleum jelly (e.g., Vaseline). [A correspondent to the British Dental Journal (Brewer, 2017) warned of "the death of a bedbound patient who smoked following application of E45 cream…a paraffin-based product, the residue of which can act as an accelerant when ignited". Smoking kills. And even more rapidly if you smother yourself in flammable oil products prior to lighting up.]
So, it seems we have a mystery.
Or, Roma Agrawal simply got it wrong.
Or, perhaps, more likely, when Roma Agrawal refers to a 'layer of phosphorus' she is using the term loosely, and is actually referring to something else. That is, the protective layer may contain one or more phosphorus compounds, but not phosphorus – just as a layer of the unreactive aluminium compound alumina stops corrosion, although aluminium itself is reactive. Is this distinction just being pedantic? Not to a science educator.
An elementary misconception
The claim that a layer of phosphorus could protect iron from corrosion is therefore not credible to the scientifically literate, but might seem perfectly reasonable to a person with limited science background. One of the great challenges of learning chemistry is making sense of the set of ideas that:
the compound of an element is a completely different substance to the element itself
the properties of compounds are often quite different (sometimes contrastingly so) to those of the elements the compound was formed from
although the compound does not behave like the elements, and does not 'contain' the elements in any straightforward way, there is a sense in which something of the elements persists in (and so the element may be recovered from) the compound.
So, sodium is a reactive metal that burns in air, and chlorine is a green, toxic, choking gas; and both should be avoided unless taking very careful precautions; yet they react, very energetically, to give the relatively unreactive compound sodium chloride – which people readily use in cooking, and to season their food, and to dissolve in water to gargle with, or to soak tired feet. Chlorine would destroy the lining of your throat. Yet sodium chloride solution (despite its chlorine 'constituent') will help ease a sore throat! Still, the sodium chloride has the potential to be 'separated' into the elements with their dangerous properties intact.
Although the distinction between elements and compounds is a lot easier to understand once students learn about molecules and atoms (at least, if avoiding the alternative conception that compounds comprise of molecules and elements comprise of atoms!) this topic is fraught with complications and hang-overs from historical ideas about atoms (Taber, 2003).
If not a layer of phosphorus?
The chemist or science teacher hearing about a protective 'layer of phosphorus' preventing rusting will immediately thinks this is not viable…but a compound of phosphorus might well have the necessary properties. Indeed, generally, the more reactive the elements, the more stable the compounds they form when reacting.
It seems that the layer that formed on the iron column contains the phosphorus compoundiron hydrogen phosphate hydrate (FePO4·H3PO4·4H2O),
"Several theories have been postulated regarding corrosion resistance of the Delhi iron pillar. Some of those refer to the inherent nature of the construction material, such as the selection of pure iron, presence of slag particles and slag coatings, surface finishing using mechanical operation, phosphate film formation, or the Delhi's climate…
Earlier studies have delineated the formation of crystalline iron hydrogen phosphate hydrate (FePO4·H3PO4·4H2O), 𝛼-, 𝛾-, 𝛿-FeOOH and magnetite in the case of Delhi iron pillar"
Yet this critical, and somewhat counter-intuitive, distinction between elements qua elements and elements as in some sense 'components' (or 'ingredients') of compounds needs to be acquired. Novices have to learn this. A common alternative conception is to assume that the properties of elements are carried over into their compounds.
So, if students hear that
phosphorus is essential in our diet, and that
phosphorus is important for healthy bones and teeth,
they can draw the obvious and reasonable conclusion – that phosphorus must be a pretty innocuous substance as it is part of our bodies and we eat it quite safely in our food. Actually, we need compounds of phosphorus in our food to allow our metabolisms to build and repair tissues that contain phosphorus compounds – and anyone misguided enough to try to eat any actual (elemental) phosphorus risks a nasty burn.
In conclusion, as a science graduate, Roma Agrawal presumably appreciates the key distinction between (i) elements as substances and (ii) elements as chemically combined components of other substances, and, as a structural engineer knowledgeable about different material properties, is using 'layer of phosphorus' as a shorthand for a layer of material that includes one or more phosphorus compounds.
That is fine as long as those hearing her talk appreciate that. Another scientist would likely automatically hear 'phosphorus layer' as meaning 'phosphorus compound containing layer'. A science teacher, however, might suspect that the reference to how "a very thin layer of phosphorus formed, between the rust and the fresh metal and basically stopped it from rusting" is likely to be misunderstood, and indeed to mislead, some listening to the podcast.
Minding your Ps…
One of the sources referred to reported how:
"P is found present in slag whereas the presence of P in iron was not detected within the limit of the analytical techniques used in this study. On the basis of this result, we speculate application of lime and other basic compounds during the iron making process which would have led to the transfer P to slag."
P is the symbol for phosphorus, the element. However, someone with a sufficient scientific background appreciates from the context that references to
P found in slag
P in iron
transfer [of] P to slag
cannot refer to P as phosphorus the element, but rather some compound or compounds of phosphorus. As a reactive element, phosphorus is not found native and so would not be present (as an element) in the raw materials and, in any case, could certainly not survive (as an element) the high temperature conditions of the processes of iron smelting. Therefore the relevant 'context' for reinterpreting 'P' as not standing for the element itself would be any set of circumstances other than the special conditions where phosphorus can be safely stored without risk of reaction.
This is the prerequisite background knowledge that prevents an audience member misinterpreting what must be meant by a "thin layer of phosphorus [sic]" protecting an exposed iron column – as it cannot possibly refer to a thin layer of [actual, elemental] phosphorus.
Sources cited
Anantharaman, T. R. (1997). The iron pillar at Delhi. In S. Ranganathan (Ed.), Iron and Steel Heritage of India (pp. 1-28). Indian Institute of Metals and Tata Steel.
Brewer, E. Patient safety: Paraffin-based products. British Dental Journal223, 620 (2017). https://doi.org/10.1038/sj.bdj.2017.936
Dwivedi, D., Mata, J. P., Salvemini, F., Rowles, M. R., Becker, T., & Lepková, K. (2021). Uncovering the superior corrosion resistance of iron made via ancient Indian iron-making practice. Scientific Reports, 11(1), 4221. doi:10.1038/s41598-021-81918-w
Falk, S. (2020). The Light Ages. A Medieval journey of discovery. Allen Lane.
Srinivasan, S., & Ranganathan, S. (2013). Minerals and Metals Heritage of India. Bangalore: National Institute of Advanced Studies.
1 A simplistic view was that advancing civilisation underwent something of a relapse during the middle ages, until the gains of the classical age (the Greeks, the Romans) were rediscovered in the Enlightenment. Thus, the term 'dark ages' applied to the 'middle ages'.
There were no dark ages: as a matter of fact, they are all dark
with apologies to Pink Floyd
That is clearly a great simplification, and ignores many medieval achievements, as well as being a rather Eurocentric view. Some historians have been seeking to redress this impression: for example, Seb Falk (2020) has renamed this period 'the light ages'.
2 To suggest that steel deliberately contains impurities added to iron could give the impression that iron artefacts are made of purer materials than steel ones. This is misleading. Basic iron smelting produces iron that is impure (sometimes known as 'pig iron') and which can contain quite high levels of impurities. Pig iron typically has a high level of carbon – more than is usually used in steels.
Wrought iron is produced by physical working of pig iron which expels much of the slag content, giving purer iron. Wrought iron has long been widely used in structures, but still does not have a high level of purity.
Alloys are mixtures of different metals, or of metallic elements with other elements. 'Metal' here is ambiguous as it can refer to
an electropositive element (the usual meaning in chemistry) or
a material with certain properties (the usual meaning in engineering) – i.e., malleable, ductile, high electrical and thermal conductivities, lustre, sonorous.
Steels are metals in the 'materials' sense, but 'chemically' are mixtures of the metallic element iron with other elements.
As the properties of steels are sensitive to the levels of other elements, making steel requires using high quality iron that has been treated to remove most of the impurities. This is similar to doping a semiconductor such as silicon to produce electronic components. Very pure silicon is needed as a starting point, so that just the right amount of a specific dopant can be added.
The Indian iron manufacture of Roman times tended to produce iron with a significant phosphorus content.
3 The column was made of wrought iron,
"The forging of wrought iron seems to have reached its zenith in India in the first millennium AD. The earliest large forging is the famous iron pillar with a height of over 7 m and weight of about 6 tons at New Delhi ascribed to Chandragupta Vikramaditya 400- 450 CE… the absence of corrosion is linked to the composition, the high purity of the wrought iron and the phosphorus content and the distribution of slag."
Srinivasan & Ranganathan, 2013
4 The lack of rusting may have been exaggerated,
"The first impression in 1961 was that the portion of the Pillar below the earth was "superficially rusted". However, on detailed examination, the buried portion of the Pillar was found covered with thick crusts of rust and, in fact, copious rust scales could be collected, ranging in thickness from a few millimeters (mm) to no less than 15 mm in some portions. Further, the bulbous base of the Pillar was found riddled with numerous cavities and hollows caused by deep corrosion and mineralization of the iron.
Anantharaman, 1997
Even so, the survival of an iron column exposed to weathering for this length of time is still worthy of note.
5 I thought I should put 'dissolve' into 'scare quotes' here. Corrosion is a chemical change, whereas dissolving refers to what is generally considered a physical change. As the sacrificial metal reacts, it releases cations into solution in the sea, in much the same was as, say, dissolving salt releases sodium ions when common salt is added to water. The metal reacts and enters solution – dissolves, if you are comfortable with that word in this context.
Have chemist's created an atomic scale Newton's cradle?
(Image by Michelle from Pixabay)
Mimicking a Newton's cradle
I was interested to read in an issue of Chemistry World that
"Scientists in Canada have succeeded in setting off a chain of reactions in which fluorine atoms are passed between molecules tethered to a copper surface. The sequence can be repeated in alternating directions, mimicking the to-and-fro motions of a Newton's cradle."
"The team of researchers…affixed fluorocarbons to a [copper] surface by chemisorption, constructing chains of CF3 molecules terminated by a CF2 molecule – up to four molecules in total….
The researchers applied an electron impulse to the foremost CF3 molecule, causing it to spit out a fluorine atom along the chain. The second CF3 absorbed this atom, but finding itself unstable, ejected its leading fluorine towards the third molecule. This in turn passed on a fluorine of its own, which was taken up by the taken up by the CF2 molecule in fourth position."
There is some interesting language here – a molecule "spits out" (a metaphor?) an atom, and another "finds itself" (a hint of anthropomorphism?) unstable.
Molecular billiards? Can a line of molecules 'tethered' onto a metal surface behave like a Newton's cradle?
Generating reverse swing
The figure below was drawn to represent the work as described, showing that "another electron impulse could be used to set… off…a reverse swing".
A representation of the scheme described in Chemistry World. The different colours used for the fluorine 'atoms' 1 are purely schematic to give a clear indication of the changes – the colours have no physical significance as all the fluorine atoms are equivalent. 2 The molecules are shown here as if atoms were simply stuck to each other in molecules (rather than having become one larger multi-nuclear structure) for the same reason. 1 In science we select from different possible models and representations for particular purposes.3
That reference to "another electron impulse" being needed is significant,
"What was more, each CF3 had been flipped in the process, so the Newton's cradle as a whole was a mirror image of how it had begun, giving the potential for a reverse swing. Unlike a desk Newton's cradle, it did not swing back on its own accord, but another electron impulse could be used to set it off."
"…the Newton's cradle as a whole was a mirror image of how it had begun"
Mirroring a Newton's cradle
Chemistry World is the monthly magazine of the Royal Society of Chemistry (a learned society and professional body for chemists, primarily active in the UK and Eire) sent to all its members. So, Chemistry World is part of the so-called secondary literature that reports, summarises, and comments on the research reports published in the journals that are considered to comprise the primary academic literature. The primary literature is written by the researchers involved in the individual studies reported. Secondary literature is often written by specialist journalists or textbook authors.
The original report of the work (Leung, Timm & Polanyi, 2021) was published in the research journal Chemical Communications. That paper describes how:
"Hot [sic] F-atoms travelling along the line in six successive 'to-and-fro' cycles paralleled the rocking of a macroscopic Newton's cradle."
Leung, Timm & Polanyi, 2021, p.12647
A simple representation of a Newton's cradle (that is, "a macroscopic Newton's cradle")
"…energised F can move to- and-fro. This occurs in six successive linear excursions, under the influence of electron-induced molecular dissociation at alternate ends of the line…. The result is a rocking motion of atomic F which mirrors, at the molecular scale, the classic to-and-fro rocking of a macroscopic Newton's cradle. Whereas a classic Newton's cradle is excited only once, the molecular analogue [4] here is subjected to opposing impulses at successive 'rocks' of the cradle.
The observed multiple knock-on of F-atoms travelling to-and-fro along a 1D row of adsorbates [molecules bound to a substrate] is shown…to be comparable with the synchronous motion of a Newton's cradle."
Leung, Timm & Polanyi, 2021, p.12647-50
Making molecules rock?
'Rocking' refers to a particular kind of motion. In a macroscopic context, there are familiar example of rocking as when a baby is cradled in the arms and gently 'rocked' back and forth.
A rocking chair is designed to enable a rocking motion where the person in the chair moves back and forth through space.
The molecular system described by Leung and colleagues is described as "mirror[ing], at the molecular scale…to-and-fro rocking"
[Image by OpenClipart-Vectors from Pixabay]
The researchers are suggesting that, in some sense, the changes in their molecular scale system are equivalent to "the synchronous motion of a Newton's cradle".
Titles and texts in scientific writing
One feature of interest here is a difference between the way work is described in the article titles and the main texts.
Chemistry society professional journal
Academic research journal
Title
"…molecular Newton's cradle"
"…an atomic-scale Newton's cradle"
Text
The effect was "mimicking … a Newton's cradle."
The effect "paralleled… mirrors… [is] comparable with" Newton's cradle
Bold titles: nuanced details
Titles need to capture the reader's attention (and in science today the amount of published material is vastly more than only one person could read) so there is a tendency to be bold. Both these articles have titles suggesting that they are reporting a nanoscopic Newton's cradle. The reader enticed to explore further then discovers that there are caveats. What is being claimed is not a Newton's cradle at minuscule scale but something which though not actually a Newton's cradle, does have some similarity to (mimics, parallels, mirrors) one.
This is important as "the molecular analogue" is only analogous in some respects.
The analogy
There is an analogy, but the analogy can only be drawn so far. In the analogy, the suspended balls of the Newton's cradle are seen as analogous to the 'chemisorbed' molecules lined up on the surface of a copper base.
Analogies are used in teaching and in science communication to help 'make the unfamiliar familiar', to show someone that something they do not (yet) know about is actually, in some sense at least, a bit like something they are already familiar with. In an analogy, there is a mapping between some aspect(s) of the structure of the target ideas and the structure of the familiar phenomenon or idea being offered as an analogue. Such teaching analogies can be useful to the extent that someone is indeed highly familiar with the 'analogue' (and more so than with the target knowledge being communicated); that there is a helpful mapping across between the analogue and the target; and that comparison is clearly explained (making clear which features of the analogue are relevant, and how).
Analogies only map some features from analogue to target. If there was a perfect transfer from one system to the other, then this would not be an analogy at all, but an identity! So, in a sense there are no perfect analogies as that would be an oxymoron. Understanding an analogy as intended therefore means appreciating which features of the analoguedo map across to the target, and which do not. Therefore in using analogies in teaching (or communicating science) it is important to be explicit about which features of the analogue map across (the 'positive' analogy) and which do not, including features which it would be misleading to seek to map across – the so called 'negative analogy.' For example, when students think of an atom as a tiny solar system, they may assume that atom, like the solar system, is held together by gravitational force (Taber, 2013).
It probably seems obvious to most science teachers that, if comparing the atom with a solar system, the role that gravity has in binding the solar system maps across to the electrical attraction between a positive nucleus and negative electrons; but when a sample of 14-18 year-olds were asked about atoms and solar systems, a greater number of them suggested the force binding the atom was gravitational than suggested it was electrical (Taber, 2013)!
Perhaps the most significant 'negative analogy' in the research discussed here was pointed out in both the research paper and the subsequent Chemistry World report, and relates to the lack of inherent oscillation in the molecular level system. The nanoscopic system is like a Newton's cradle that only has one swing, so the owner has to reset it each half cycle.
"Unlike a desk Newton's cradle, it did not swing back on its own accord, but another electron impulse could be used to set it off."
"Whereas a classic Newton's cradle is excited only once, the molecular analogue here is subjected to opposing impulses at successive 'rocks' of the cradle"
That is quite a major difference when using the Newton's cradle for an analogy.
Image by Peggy und Marco Lachmann-Anke from PixabayImage by Peggy und Marco Lachmann-Anke from Pixabay
Who wants a Newton's cradle as an executive toy if it needs to be manually reset after each swing?
The positive and negative analogies
We can consider that the Newton's cradle is a little like a simple pendulum that swings back and forth, with the complication that instead of a single bob swinging back and forth, the two terminal spheres share the motion between them due to the momentum acquired by one terminal sphere being transferred thorough the intermediate spheres to the other terminal sphere.
In understanding the analogy it is useful to separately consider these two features of a Newton's cradle
a) the transfer of momentum through the sequence
b) moving a mass through a gravitational field
If we then think of the Newton's cradle as a 'pendulum with complications' it seems that the molecular system described by Leung and colleagues fails to share a critical feature of a pendulum.
A chain reaction – the positive analogy
The two systems map well in so far as that they comprise a series of similar units (spheres, molecules) that are carefully aligned, and constrained from moving out of alignment, and that there is a mechanism that allows a kind of chain reaction.
In the molecular scenario, the excitation of a terminal molecule causes a fluorine atom to become unbound from the molecule and to carry enough momentum to collide with and excite a second molecule, binding to it, whilst causing the release of one of the molecule's original fluorine atoms which is similarly ejected with sufficient momentum to collide with the next molecule…
This 'chain reaction' 5 is somewhat similar to how, in a Newton's cradle, the momentum of a swinging sphere is transferred to the next, and then to the next, and then the next, until finally all the momentum is transferred to the terminal sphere. (This is an idealised cradle, in any real cradle the transfer will not be 100% perfect.) This happens because the spheres are made from materials which collide 'elastically'.6
The positive analogy: The notion of an atomic level Newton's cradle makes use of a similarity between two systems (at very different scales) where features of one system map onto analogous features of the other.
The negative analogy
Given that positive mapping, a key difference here is the way the components of the system (suspended spheres or chemisorbed molecules) are 'tethered'.
Chemisorbed molecules
The molecules are attached to the copper surface by chemical bonding, which is essentially an electromagnetic interaction. A sufficient input of energy could certainly break these bonds, but the the impulse being applied parallel to the metal surface is not sufficient to release the molecules from the substrate. It is enough to eject a fluorine atom from a molecule where carbon is already bound to the surface and three other fluorines atoms (carbon is tetravalent, but it is is bonded to the copper as well as the fluorines) – but the final molecule is an adsorbed CF2 molecule, which 'captures' the fluorine and becomes an absorbed CF3 molecule.
Now, energy is always conserved in all interactions, and momentum is also always conserved. If the kinetic energy of the 'captured' fluorine atom does not lead to bond breaking it must end up somewhere else. The momentum from the 'captured' atom must also be transferred somewhere.
Here, it may be useful to think of chemical bonds as having a similarity to springs – in the limited sense that they can be set vibrating. If we imagine a large structure made up of spheres connected by springs, we can see that if we apply a force to one of the spheres, and the force is not enough to break the spring, the sphere will start to oscillate, and move any spheres connected to it (which will move spheres attached to them…). We can imagine the energy from the initial impulse, and transferred through the chain of molecules, is dissipated though the copper lattice, and adds to its internal energy. 7
The fluorocarbon molecules are bound to the surface by chemical bonding. If the energy of impact is insufficient to cause bond breaking, it will be dissipated.
Working against gravity
In a simple pendulum, work is done on a raised sphere by the gravitational field, which accelerates the bob when it is released, so that it is moving at maximum speed when it reaches the lowest point. So, as it is moving, it has momentum, and its inertia means it continues to swing past the equilibrium position which is the 'attractor' for the system. In a Newton's cradle the swinging sphere cannot continue when it collides with the next sphere, but as its momentum is transferred through the train of spheres the other terminal sphere swings off, vicariously continuing the motion.
In an ideal pendulum with no energy losses the bob rises to its original altitude (but on the other side of the support) by which time it has no momentum left (as gravitational force has acted downwards on it to reduce its momentum) – but gravitational potential energy has again built up in the system to its original level. So, the bob falls under gravity again, but, being constrained by the wire, does not fall vertically, rather it swings back along the same arc.
It again passes the equilibrium position and returns to the point where it started, and the process is repeated. In an ideal pendulum this periodic oscillation would continue for ever. In a real pendulum there are energy losses, but even so, a suitable bob can swing back an forth for some time, as the amplitude slowly reduces and the bob will eventually stop at the attractor, when the bob is vertical.
In a (real) Newton's cradle, one ball is raised, so increasing the gravitational potential energy of the system (which is the configuration of the cradle, with its spheres, plus the earth). When it is released, gravity acts to cause the ball to fall. It cannot fall vertically as it is tethered by a steel (or similar) wire which is barely extendible, so the net force acting causes the ball to swing though an arc, colliding with the next ball.
The Newton's cradle design allows the balls to change their 'height' in relation to a vertical gravitational field direction – in effect storing energy in a higher gravitational field configuration that can do work to continue the oscillation. The molecular analogue 4 does not include an equivalent mechanism that can lead to simultaneous oscillation. (Image by 3D Animation Production Company from Pixabay)
Two types of force interactions
The steel spheres, however, are actually subject to two different kinds of force. They are, like the molecules, also tethered by the electromagnetic force (they are attached to steel wires which are effectively of fixed length due to the bonding in the metal 8), but, in addition, subject to the gravitational field of the earth. 9 The gravitational field is relevant because a sphere is supported by a wire that is fixed to a rigid support (the cradle) at one end, but free to swing at the end attached to the sphere.
The Newton's cradle operates in what is in effect a uniform gravitational field (neither the radial nature or variation with altitude of the earth's field are relevant on the scale of the cradle) – and the field direction is parallel to the plane in which the balls hang. So, the gravitational potential of the system changes as a sphere swings higher in the field.
In a Newton's cradle, a tethered sphere's kinetic energy allows it to rise in a gravitational field, before swinging back gaining speed (and regaining kinetic energy)
The design of the system is such that a horizontal impulse on a sphere leads to it swinging upwards – and gravity then acts to accelerate it towards a new collision. 10 This collision, indirectly, gives a horizontal impulse to the sphere at the other end of the 'train' where again the nature of the support means the sphere swings upward – being constrained by both the wire maintaining its distance from the point of suspension at the rigid support of the frame, and its weight acting downwards.
The negative analogy concerns the means of constraining the system components
The two systems then both have a horizontal impulse being transferred successively along a 'train' of units. Leung and colleagues' achievement of this at the molecular scale is impressive.
However, the means of 'tethering' in the two systems is different in two significant ways. The spheres in the Newton's cradle are suspended from a rigid frame by inextensible wires that are free to swing. Moreover, the cradle is positioned in a field with a field direction perpendicular to the direction of the impulse. This combination allows horizontal motion to be converted to vertical motion reversibly.
The molecular system comprises molecules bound to a metal substrate. The chemisorbtion is less like attaching the molecules with long wires that are free to swing, and more like attaching them with short, stiff springs. Moreover, at the scale of the system, the substrate is less like a rigid frame, and more like a highly sprung mattress. So, even though kinetic energy from the 'captured' fluorine atom can be transferred to the bond, this can then be dissipated thorough the lattice.
The negative analogy: the two systems fail to map across in a critical way such that in a Newton's cradle one initial impulse can lead to an extended oscillation, but in the molecular system the initiating energy is dissipated rather than stored to reverse the chemical chain reaction.
The molecular system does not enable the terminal molecule to do work in some form that can be recovered to reverse the initial process. By contrast, a key feature of a Newton's cradle is that the spheres are constrained ('tethered') in a way that allows them to move against the gravitational field – they cannot move further away from, nor nearer to, their point of support, yet they can swing up and down and change their distance from the earth. Mimicking that kind of set-up in a molecular level system would indeed be an impressive piece of nano-engineering!
Work cited:
Blow, M. (2022). Molecular Newton's cradle challenges theory of transition states. Chemistry World, 19(1), 38.
Leung, L., Timm, M. J., & Polanyi, J. C. (2021). Reversible 1D chain-reaction gives rise to an atomic-scale Newton's cradle. Chemical Communications, 57(94), 12647-12650. doi:10.1039/D1CC05378G
Taber, K. S. (2013). Upper Secondary Students' Understanding of the Basic Physical Interactions in Analogous Atomic and Solar Systems. Research in Science Education, 43(4), 1377-1406. doi:10.1007/s11165-012-9312-3 (The author's manuscript version may be downloaded here.)
Notes
1Strictly they are no distinct atoms once several atoms have been bound together into a molecule, but chemists tend to talk in a shorthand as if the atoms still existed in the molecules.
2 Whilst I expect this is obvious to people who might choose to read this posting, I think it is worth always being explicit about such matters as students may develop alternative conception at odds with scientific accounts.
In the present case, I would be wary of a learner thinking along the lines "of course the atom will go back to its own molecule"
Students will commonly transfer the concepts of 'ownership' and 'belonging' from human social affairs to the molecular level models used in science. Students often give inappropriate status to the history of molecular processes (as if species like electrons recall and care about their pasts). One example was a student who suggested to me that in homolytic bond breaking each atom would get its own electron back – meaning the electrons in the covalent bond would return to their 'own' atoms.
I have also been told that in double decomposition (precipitation) reactions the 'extra' electron in an anion would go back to its own cation in the reagents, before the precipitation process can occur (that is, precipitation was not due to the mutual attraction between ions known to be present in the reaction mixture: they first had to become neutral atoms that could then from an ionic bond by electron transfer!) In ionic bonding it is common for learners to think that an ionic bond can only be formed between ions that have been formed by a (usually fictitious) electron transfer event.
3 I have here represented the same molecules both as atoms linked by bonds (where I am focusing on the transfer of fluorine atoms) and in other diagrams as unitary spheres (where I am focusing on the transfer of energy/momentum). All models and representations used for atoms and molecules are limited and only able to reflect some features of what is being described.
4 A note on terminology. An analogy is used to make the unfamiliar familiar by offering a comparison with something assumed to already be familiar to an audience, in this case the molecular system is the intended target, and the (that is, a generic) Newton's cradle is the analogue. However, analogy – as a mapping between systems – is symmetrical so each system can be considered the analogue of the other.
5 In some way's Leung's system is more like a free radical reaction than a Newton's cradle. A free radical is an atom (or molecule) with an unpaired electron – such as an unbound fluorine atom!
In a free radical reaction a free radical binds to a molecule and in doing so causes another atom to be ejected from the molecule – as a free radical. That free radical can bind to another molecule, again causing it to generate a new free radical. In principle this process can continue indefinitely, although the free radical could also collide with another free radical instead of a molecule, which terminates the chain reaction.
6 The balls need to be (near enough) perfectly elastic for this to work so the total amount of kinetic energy remains constant. Momentum (mv) is always conserved in any collision between balls (or other objects).
If there were two balls, then the first (swinging) sphere would be brought to a stop by the second (stationary) sphere, to which its momentum would be transferred. So, the first ball would stop swinging, but the second would swing in its place. The only way mvandmv2(and so kinetic energy) can be both conserved in collisions between balls of the same mass is if the combination of velocities does not change. That is, mathematically, the only solutions are where neither of the two balls' velocities change, or where they are swapped to the other permutation (here, the velocity of the moving ball becomes zero, but the stationary ball moves off with the velocity that the ball that hit it had approached it with).
The first solution would require the swinging steel ball to pass straight through the stationary steel ball without disturbing it. Presumably, quantum mechanics would suggest that ('tunnelling') option has a non-zero (but tiny, tiny – I mean really tiny) probability. To date, in all known observations of Newton's cradles no one has reported seeing the swinging ball tunnel though the stationary ball. If you are hoping to observe that, then, as they say, please do not hold your breath!
With more balls momentum is transferred through the series: only the final ball is free to move off.
7 We can imagine that in an ideal system of a lattice of perfectly rigid spheres attached to perfect springs (i.e., with no hysteresis) and isolated from any other material (n.b., in Leung et al 's apparatus the copper would not have been isolated from other materials), the whole lattice might continue to oscillate indefinitely. In reality the orderliness will decay and the energy will have in effect warmed the metal.
8 Strictly, the wires will be longest when the spheres are directly beneath the points of support, as the weight of a sphere slightly extends the wire from its equilibrium length, and it will get slightly shorter the further the sphere swings away from the vertical position. In the vertical position, all the weight is balanced by a tension in the wire. As the ball swings away from the vertical position, the tension in the wire decreases (as only the component of weight acting along the wire needs to be balanced) and an increasing component of the weight acts to decelerate it. But the change in extension of the wire is not significant and is not noticeable to someone watching a Newton's cradle.
When the wire support is not vertical a component of the weight of the sphere acts to change the motion of the sphere
9 Molecules are also subject to gravity, but in condensed matter the effect is negligible compared with the very much stronger electromagnetic forces acting.
10 We might say that gravity decelerates the sphere as is swings upwards and then accelerates as it swings back down. This is true because that description includes a change of reference direction. A scientist might prefer to say that gravity applies a (virtually) constant downward acceleration during the swing. This point is worth making in teaching as a very common alternative conception is to see gravity only really taking effect at the top of the swing.
it seems good training for a scientist to always read accounts of science with a critical filter primed to notice figurative language and to check that the communication can be understood in a non-metaphorical way
When water is poured from a bottle or other container the stream of liquid can take up complex shapes. In particular, it has long been noted how the stream can appear to have the shape of a chain or string of beads, with the flow seeming to be wider in some places that others.
A stream of poured water does not form a perfect cylinder – something that physics should be able to explain.
(Image by tookapic from Pixabay)
This is just the kind of thing that physicists think they should be able to explain…using physics. An article in Physics World (Jarman, 2022) reports some recent work on just this outstanding problem,
"If you pour water out of a bottle, the liquid stream will often adopt a chain-like structure….At the heart of the effect is the non-cylindrical profile of the jet as it emerges. To minimize surface tension, the jet tries to become a cylinder, but this motion overshoots and results in an oscillation in the profile shape."
What intrigued me here was the choice of phrasing: "To minimize surface tension, the jet tries to become a cylinder…". This language could be considered to reflect teleology, and even anthropomorphism.
Teleology?
Teleological explanations are those that explain something in terms of some kind of endpoint. Something happens in order to bring about some specific state of affairs. The sun shines to allow us to find our way. Plants produce oxygen so we can breathe. That is, there is seen to be purpose in nature, something that is characteristic of mythical and supernatural thinking. In science, teleological explanations are strictly considered a kind of pseudo-explanation – something that has the form of an explanation, but does not really explain anything. Sometimes we find apparently teleological explanations in science because they are being used as a kind of shorthand. For example, if we know that science suggests entropy always increases in processes, we might interpret a scientist's comment that something happens 'in order to increase entropy' to be a loose (or lazy) way of saying that some suggested mechanism or action is considered likely because it is consistent with the assumption that entropy will increase.
Here it is suggested that the odd shape is formed in order "to" minimise surface tension. Scientists have observed that many phenomena (such as rain forming roundish drops) can be explained in terms that surface tension tends to be minimised (cf. entropy tends to increase, objects tend to roll down hills, people tend to get older). But the language here might suggest minimising surface tension is an end that nature seeks – that would be a teleological explanation.
Although perhaps this is not simple teleology, as it is not that the water forms into the shape it does to minimise surface tension, but something more nuanced is going on – the jet of water is actively trying, but not quite managing, to minimise surface tension.
anthropo… (to do with humans, as in anthropology) …morphism (to do with form, as in morphology, amorphous)
…and anthropomorphism?
Anthropomorphic language refers to non-human entities as if they have human experiences, perceptions, and motivations. Both non-living things and non-human organisms may be subjects of anthropomorphism. Anthropomorphism may be used deliberately as a kind of metaphorical language that will help the audience appreciate what is being described because of its similarly to some familiar human experience. In science teaching, and in public communication of science, anthropomorphic language may often be used in this way, giving technical accounts the flavour of a persuasive narrative that people will readily engage with. Anthropomorphism may therefore be useful in 'making the unfamiliar familiar', but sometimes the metaphorical nature of the language may not be recognised, and the listener/reader may think that the anthropomorphic description is meant to be taken at face value. This 'strong anthropomorphism' may be a source of alternative conceptions ('misconceptions') of science.
So, in our present case, we are told that "the "the jet tries to become a cylinder". This is anthropomorphic, as to try to do something means having a goal in mind and deliberately behaving in a way that it is believed, expected, or – at least – hoped, will lead to that goal. Human beings can try to achieve things. We can perceive our environment, have goals, conceptualise possibilities and means to reach them, and put in practice an intention.
Whether, and, if so, which, animals can try to do things rather than simply following evolved instincts is a debated issue.
Does a dog try to please its human companion by bringing the newspaper?
Does the dolphin try to earn a fish by jumping through a hoop? Perhaps.
Does the salmon try to get to a suitable spawning site ('ground', sic) by swimming upstream?
Does the spider try to make a symmetrical web?
Does the bee try to collect nectar by visiting flowers. Probably not.
Does she try to fertiliser those flowers with pollen to ensure there will be flowers for her to visit in future seasons? Almost certainly not!
Jets of water?
Do jets of water think that being cylindrical is desirable (perhaps because they recognise minimal surface tension as an inherent good?) , and so make efforts to bring this about? Clearly not. So, they do not try to do this. They do not try to do anything. They are not the kind of entities that can try.
So, this language is metaphorical. The reader is meant to read that "the jet tries to become a cylinder" to mean something other than "the jet tries to become a cylinder". Now, often figures of speech are used in science communication because the ideas being communicated are abstract and complex, and metaphorical language that describes the science in more familiar terms makes the text more accessible and increases engagement by the audience/readership.
A question here then, is what "the jet tries to become a cylinder" communicates that was more likely to be inaccessible to the reader. Physics Worldis the house magazine of the Institute of Physics, which means it is sent to all it members working across all areas of physics. So a broad readership, though largely a readership of physicists.
Tracing the stream back to the source
Another question that occurred to me was whether the reporter (Jarman) was simply reporting the original researchers' (Jordan, Ribe, Deblais and Bonn) ways of communicating their work. That report was in an academic journal, Physical Review Fluids, where formal, technical language would be expected. So, I looked up the paper, to see how the work was described there.
Under a heading of 'phenomenology', Jordan and colleagues explain
"Chain oscillations are most readily observed when the viscosities of the jet and the ambient fluid are low and the interface has a high surface tension. Water jets in air satisfy these criteria, and so it is no surprise that chain oscillations occur in many everyday situations. Deformation and vibration of a jet are capillary phenomena in which surface tension acts to reduce the jet's surface area. If the cross section is not circular, its highly curved portions are pulled inward and its weakly curved portions pushed outward relative to a circular section with the same area. But due to inertia the movement overshoots, with the result that the long and short axes of the section are interchanged. The shape of the section therefore evolves as it moves along the axis of the jet, producing a steady liquid chain when observed in the laboratory frame…"
Jordan, Ribe, Deblais & Bonn, 2022
"The shape of the section therefore evolves as it moves along the axis of the jet, producing a steady liquid chain when observed"
(Image by Kevin Phillips from Pixabay)
(This seemed to be a somewhat different meaning of 'phenomenology' to that sometimes used in science education or social science more generally. Phenomenology looks to explore how people directly experience and perceive the world. Jordan and colleagues include here a good deal of re-conceptualisation and interpretation of what is directly observed. 1 )
The effect Jordan and colleagues describe seems analogous to how a pendulum bob that is released and so accelerated (by gravity) towards the point directly beneath its support (where gravitational potential is minimised) acquires sufficient momentum to overshoot, and swing upwards, beginning an oscillatory motion. Something similar is seen in an ammeter where the needle often overshoots, and initially oscillates around the value of a steady current reading (unless the spring is 'critically damped'). The effect is also made use on in striking a tuning fork.
No need to try
There is no mention here of 'trying', so no clear anthropomorphism. So, this was a gloss added in the report in Physics World, perhaps because anthropomorphic narratives are especially engaging and readily accepted by audiences; perhaps because the reporter needed to rephrase so as not to borrow too much of the original text, or perhaps as part of preparing brief copy to an editorially assigned word length. Or, perhaps Sam Jarman was not even conscious of the anthropomorphism being used, as this seems such a natural way to communicate. 2
Surface tension acting up
Did the original authors avoid teleology? They do write about how "surface tension acts to reduce the jet's surface area?" This could be read as teleological – as there seems to be a purpose or goal in the 'action', even if it is not here presented as a premeditated action. Could any suggestions of such a purpose be avoided?
One response might be that, yes, a physicist might suggest the 'true' description is a mathematical formula (and there are plenty of formulae in Jordan et al's paper) and that a verbal description is necessarily the translation of an objective description into an inherently figurative medium (natural language).
And, of course, this is not some special case. We might read that gravity acts to pull something to the ground or air resistance acts to slow a projectile down and so forth. 'To' may just imply a cause of an outcome, not a purpose.
I think a rewording along the lines "the action of the surface tension reduces the jet's surface area"conveys the same meaning, but is more of a neutral description of a process, avoiding any suggestion that there is a purpose involved.
Reading and interpreting
But does this matter? In teaching young people such as school children, there is evidence that some figurative language that is anthropomorphic or teleological may be understood in those terms, and student thinking may later reflect this. Part of science education is offering learners an insight into how science does seek to (oh, science personified: sorry, scientists seek to) describe in neutral terms and not to rely on nature having inherent goals, or comprising of the actions of sentient and deliberate agents.
The readership of Physics World is however a professional audience of members of the community of inducted physicists who are well aware that, actually, surface tension does not try to do anything; and that minimising surface tension is a common observed pattern, not something set out as a target for physical systems to aim for. These physicists are unlikely to be led astray by the engaging prose of Sam Jarman and will fully appreciate the intended meaning.
That said, there is an intimate bidirectional relationship between our thinking and our speech – our speech reflects our thought pattens, but our language also channels our thinking. So, it seems good training for a scientist to always read accounts of science with a critical filter primed to notice figurative language and to check that the communication can be understood in a non-metaphorical way. That includes checking that our understanding of what we have read is in keeping with scientific commitments to exclude explanations that are framed in terms of nature's end goals, or the deliberate agency of non-sentient 'actors'.
Jarman, S. (2022). Flowing liquid 'chains' are best described by Niels Bohr, not Lord Rayleigh. Physics World, 35(12).
Jordan, D. T. A., Ribe, N. M., Deblais, A., & Bonn, D. (2022). Chain oscillations in liquid jets. Physical Review Fluids, 7(10), 104001. doi:10.1103/PhysRevFluids.7.104001
Notes
1 However, none of us are able to be completely naive observers of the world. As William James long ago pointed out, the un-mediated sensory experience of a newborn is a chaos of noise and shapes and colours and so on. Even recognising another person or the presence of a table is an act of interpretation that we learn.
So, experts in a field do see things others do not. A field palaeontologist sees a fossil fragment where the rest of us see undifferentiated dirt and stones. The biochemist sees a steroid structure in a patterns of lines. The football pundit sees a 4-4-2 formation where the occasional viewers just sees people running around. The experienced poker player sees a 'tell' that others would not notice. The professional musician hears a passage in E minor, when most of us just hear a tune.
2 This kind of language reflects a way of thinking and talking often called 'the natural attitude'. Science can be seen in part as a deliberate move to look beyond the common-sense world of the natural attitude to problematise phenomena that might be readily taken as given.
We may get used to, and simply accept, that ice is cold, fire burns, the Lord/King makes decisions and owns the land (and people!), rivers flow, things fall down, the heretic must die, the sun moves across the sky, etc. – and probably most people did for much of human history – where the critical (scientific) attitude is to always ask 'why?'
"After a lecture on cosmology and the structure of the solar system, James [William James] was accosted by a little old lady.
'Your theory that the sun is the centre of the solar system, and the earth is a ball which rotates around it has a very convincing ring to it, Mr. James, but it's wrong. I've got a better theory,' said the little old lady.
'And what is that, madam?' inquired James politely.
'That we live on a crust of earth which is on the back of a giant turtle.'
Not wishing to demolish this absurd little theory by bringing to bear the masses of scientific evidence he had at his command, James decided to gently dissuade his opponent by making her see some of the inadequacies of her position.
'If your theory is correct, madam,' he asked, 'what does this turtle stand on?'
'You're a very clever man, Mr. James, and that's a very good question,' replied the little old lady, 'but I have an answer to it. And it's this: The first turtle stands on the back of a second, far larger, turtle, who stands directly under him.'
'But what does this second turtle stand on?' persisted James patiently.
To this, the little old lady crowed triumphantly,
'It's no use, Mr. James – it's turtles all the way down.'
Ross, 1967, iv
"The Hindoos [sic] held the earth to be hemispherical, and to be supported like a boat turned upside down upon the heads of four elephants, which stood on the back of an immense tortoise. It is usually said that the tortoise rested on nothing, but the Hindoos maintained that it floated on the surface of the universal ocean. The learned Hindoos, however, say that these animals were merely symbolical, the four elephants meaning the four directions of the compass, and the tortoise meaning eternity." (The Popular Science Monthly, March, 1877; image via Wikipedia)
It's metaphors all the way down
A well-known paper in the journal 'Cognitive Science' is entitled 'The metaphorical structure of the human conceptual system' (Lakoff & Johnson, 1980). What the authors meant by this was that metaphor, or perhaps better analogy, was at the basis of much of our thinking, and so our language.
This links to the so-called 'constructivist' perspective on development and learning, and is of great significance in both the historical development of science and in science teaching and learning. Consider some of the concepts met in a science course (electron, evolution, magnetic flux, hysteresis, oxidation state, isomerism…the list is enormous) in comparison to the kind of teaching about the world that parents engage in with young children:
That is a dog
That is a tree
That is round
This is hot
This is aunty
etc.
Pointing out the names of objects is not a perfect technique – just as scientific theories are always underdetermined by the available data (it is always possible to devise another scheme that fits the data, even if such a scheme may have to be forced and convoluted), so the 'this' that is being pointed out as a treecould refer to the corpse of trees, or the nearest branch, or a leaf, or this particular species of plant, or even be the proper name of this tree, etc. 1
Pointing requires the other person to successfully identify what is being pointed at (Images by Joe {background} and OpenClipart-Vectors {figures} from Pixabay)
But, still, the 'this' in such a case is usually more salient than the 'this' when we teach:
This is an electron
This is reduction
This is periodicity
This is electronegativity
This is a food web
This is a ᴨ-bond
This is a neurotransmitter
etc.
Most often in science teaching we are not holding up a physical object or passing it around, but offering a 'this' which is at best a model (e.g., of a generalised plant cell or a human torso) or a complex linguistic structure (a definition in terms of other abstractconcepts) or an abstract representation ('this', pointing to a slope of an a graph, is acceleration; 'this', pointing to an image with an arrangement of a few letters and lines, is a transition state…).
So, how do we bridge between the likes of dogs and trees on one hand and electrons and the strong nuclear force on the other (so to speak!)? The answer is we build using analogy and we talk about those constructions using a great deal of metaphor.2 That is, we compare directly, or indirectly, with what we can experience. This refers to relationships as well as objects. We can experience being on top of, beneath, inside, outside, next to, in front of, behind, near to, a long way from (a building, say – although hopefully not beneath in that case), and we assign metaphorical relationships in a similar way to refer to abstract scenarios. (A chloroplast may be found in a cell, but is sodium found in (or on) the periodic table? Yes, metaphorically. And potassium is found beneath it!)
In a wall, the bricks on the top layer are supported by the bricks in the layer beneath – but those are in turn supported by those beneath them.
In building, we have to start at the foundations, and build up level by level. The highest levels are indirectly supported by the foundations.
(Image by OpenClipart-Vectors from Pixabay)
In science, we initially form formal concepts based on direct experience of the world (including experience mediated by our interventions, i.e., experiments), and then we build more abstractconcepts from those foundational concepts, and then we build even more abstractconcepts by combining the abstract ones. In the early stages we refine 'common sense' or 'life-world' categories into formal concepts so we can more 'tightly' (and operationally, through standard procedures) define what count as referents for scientific terms (Taber, 2013). So, the everyday phenomenon of burning might be reconceptualised as combustion: a class of chemical reactions with oxygen.
This is not just substituting a technical term, but also a more rigid and theoretical (abstract) conceptualisation. So, in the 'life-world' we might admit the effects of too much sunshine or contact with a strong acid within the class of 'burning' by analogywith the effect of fire (it hurts and damages the skin); but the scientific categorisation is less concerned with direct perception, and more with explanation and mechanism. So, iron burning in chlorine (in the absence of any oxygen) is considered combustion, but an acid 'burn' is not.
This is what science has done over centuries, and is also what happens in science education. So, one important tool for the teacher is concept analysis, where we check which prerequisite concepts need to be part of a student's prior learning before we introduce some newconcept that is built upon then (e.g., do not try to teach mass spectroscopy before teaching about atomic structure, and do not teach about atomic structure before introducing the notion of elements; do not try to teach about the photoelectric effect to someone who does not know a little about the structure of metals and the nature of electromagnetic radiation.)
This building up of abstractconcepts, one on another, is reflected in the density of metaphor we find in our language. (That is a metaphorical 'building', metaphorically placed one upon another, with a metaphorical 'density' which is metaphorically 'inside' the language and which metaphorically 'reflects' the (metaphorical) building process! You can 'see' (a metaphor for understand) just how extensive (oops, another metaphorical reference to physical space) this is. Hopefully, the (metaphorical) 'point' is (metaphorically) 'made', and so I am going to stop now, before this gets silly. 3
A case study of using language in science communication: the death of stars
Rather, I am going to discuss some examples of the language used in a single science programme, a BBC radio programme/podcast in the long-running series 'In Our Time' that took as its theme 'The Death of Stars'. The programme was hosted by Melvyn Bragg, and The Lord Bragg's guests were Professors Carolin Crawford (University of Cambridge), the Astronomer Royal Martin Rees (University of Cambridge) and Mark Sullivan (University of Southampton). This was an really good listen (recommended to anyone with an interest in astronomy), so I have certainly not picked it out to be critical, but rather to analyse the nature of some of the language used from the perspective of how that language communicates technical ideas.
An episode of 'In Our Time' on 'The Death of Stars' "The image above is of the supernova remnant Cassiopeia A, approximately 10,000 light years away, from a once massive star that died in a supernova explosion that was first seen from Earth in 1690"
A science teacher may be familiar with stars being born, living, and dying – but how might a young learner, new to astronomical ideas, make sense of what was meant?
Now there is already a point of interest in the episode title. Are stars really the kind of entities that can die? Does this mean they are living beings prior to death?
There are a good many references in the talk of these three astronomers in the episode that suggests that, in astronomy at least, stars do indeed live and die. That is, this does not seem to be consciously used as a metaphor – even if the terminology may have initially been introduced that way a long time ago. The programme offered so much material on this theme, that I have separated it out for a post of its own:
"So, in the language of astronomy, stars are born, start young, live; sometimes living alone but sometimes not, sometimes have complicated lives; have lifetimes, reach the end of their lives, and die, so, becoming dead, eventually long dead; and indeed there are generations of stars with life-cycles."
In this post I am going to consider some of the other language used.
Making the unfamiliar familiar
Language is used in science communication to the public, as it is in teaching, to introduce abstract technical ideas in ways that a listener new to the subject can make reasonable sense of. The constructivist perspective on learning tells us that meaning is not automatically communicated from speaker (or author or teacher) to listener (or reader or student). Rather, a text (spoken or written, or even in some other form – a diagram, a graph, a dance!) has to be interpreted, and this relies on the interpretive resources available to the learner. 4 The learner has to relate the communication to something familiar, and the speaker can help by using ways to make the new idea seem like something already familiar.
This is why it it is so common in communicating science to simplify, to use analogies and similes, to gesture, to use anthropomorphism and other narrative devices. There was a good deal of this in the programme, and I expect I have missed some examples. I have divided my examples into
simplifications: where some details are omitted so not to overburden the listener;
anthropomorphism: where narratives are offered such that non human entities are treated as if sentient actors, with goals, that behave deliberately;
analogies where an explicit comparison is made to map a familiar concept onto the target concept being introduced; 5
similes and metaphors: that present the technical material as being similar to something familiar and everyday.
Simplification
Simplification means ignoring some of the details, and offering a gloss on things. The details may be important, but in order to get across some key idea it is introduced as a simplification. Progress in understanding would involve subsequently filling in some details to develop a more nuanced understanding later.
In teaching there are dangers in simplification, as if the simplified idea is readily latched onto (e.g., there are two types of chemical bonds: ionic and covalent) it may be difficult later to shift learners on in their thinking. This may mean that there is a subtle balance to be judged between
giving learners enough time to become comfortable with the novel idea as introduced in a simplified form,
and
seeking to develop it out into a more sophisticated account before it become dogma.
In a one-shot input, such as a public lecture or appearance in the media, the best a scientist may be able to do is to present an account which is simple enough to understand, but which offers a sense of the science.
Simplification: all elements/atoms are formed in stars
When introducing the 'In Our Time' episode, Lord Bragg suggested that
"…every element in our bodies, every planet, was made in one of those stars, either as they burned, or as they exploded".
Clearly Melvyn cannot be an expert on the very wide range of topics featured on 'In our time' but relies on briefing notes provided by his guests. Later, in the programme he asks Professor Rees (what would clearly be considered a leading question in a research context!) "Is the sun recycled from previous dead stars?"
"Yes it is because we believe that all pristine material in the universe was mainly just hydrogen and helium, and all the atoms we are made of were not there soon after the big bang. They were all made in stars which lived and died before our solar system formed. And this leads to the problem of trying to understand more massive stars which have more complicated lives and give rise to supernovae…
The cloud from which our solar system formed was already contaminated by the debris, from earlier generations of massive stars which had lived and died more than say five billion years ago so we're literally the ashes of those long dead stars or if you are less romantic we're the nuclear waste from the fuel that kept those old stars shining."
Prof. Martin Rees
There is a potential for confusion here.
"…all the atoms we are made of were not there soon after the big bang. They were all made in stars which lived and died before our solar system formed…"
seems to be meant to convey something like
not all the atoms we are made of were there soon after the big bang. [Some were, but the rest/others] were all made in stars which lived and died before our solar system formed…
A different interpretation (i.e., that all atoms/elements are formed in stars) might well be taken, given Lord Bragg's introductory comments.
Professor Rees referred to how "…the idea that the elements, the atoms we are made of, were all synthesised in stars…" first entered scientific discourse in 1946, due to Fred Hoyle, and to
"this remarkable discovery that we are literally made of the ashes of long dead stars"
Prof. Martin Rees
Before the first star formation, the only elements present in the universe were hydrogen and helium (and some lithium) and the others have been produced in subsequent high energy nuclear processes. Nuclear fusion releases energy when heavier nuclei are formed from fusing together lighter ones, up to iron (element 56).
Forming even heavier elements requires an input of energy from another source. It was once considered that exploding stars, supernovae, gave rise to the conditions for this, but recently other mechanisms have been considered: and Prof. Sullivan described one of these:"we think these combining neutron stars are the main sites where heavy elements like strontium or plutonium, perhaps even gold or silver, these kinds of elements are made in the universe in these neutron stars combining with each other".
A human body includes many different elements, though most of these in relatively small amounts. Well represented are oxygen, carbon, calcium, and nitrogen. These elements exist because of the processes that occur in stars. However, hydrogen is also found in 'organic' substances such as the carbohydrates, proteins, and fats found in the human body. Typically the molecules of these substances contain more hydrogen atoms than atoms of carbon or any other element.
substance
formula
glucose (sugar)
C6H12O6
leucine (amino aid)
C6H13NO2
leukotriene B4 (inflammatory mediator)
C20H32O4
thymine (nucleobase)
C5H6N2O2
adreneline (hormone)
C9H13NO3
insulin (hormone)
C257H383N65O77S6
cholesterol (lipid)
C27H46O
cobalamin (vitamin B12)
C63H88CoN14O14P
formulae of some compounds found in human bodies
The body is also said to be about 60% water, and water has a triatomic molecule: two hydrogen atoms to one of oxygen (H2O). That is, surely MOST of "the atoms we are made of" are hydrogen, which were present in the universe before any stars were 'born'.
So, it seems here we have a simplification ("every element in our bodies…was made in one of those stars, either as they burned, or as they exploded"; "atoms we are made of … were all made in stars") which is contradicted later in the programme. (In teaching, it is likely the teacher would feel the need to draw the learner's attention to how the more detailed information was actually developing an earlier simplification, and not leave a learner to work this out for themselves.)
Simplification: mass is changed into energy
Explaining nuclear fusion, Prof. Crawford suggested that
"Nuclear fusion is when you combine nuclei of elements to form heavier elements, and when you do this there is a loss of mass, which is converted to energy which provides the thermal pressure and that is what counteracts the gravity and stalls the gravitational collapse."
Actually, as discussed before here, this is contrary to the scientific account. The equation presents an equivalencebetween mass and energy, but does not suggest they can be inter-converted. In nuclear fusion, the masses of the new nuclei are very slightly less than the masses of the nuclei which react to form them (the difference is known as the mass defect), but this is because this omits some details of the full description of the process. If the complete process is considered then there is no loss of mass, just a reconfiguration of where the mass can be located.
Although the 4He formed has slightly less mass than four 1H; the positrons, neutrinos and gamma rays produced all have associated (energy and) mass, so that overall there is conservation of mass.
This is a bit like cooking some rice, and finding that when the rice is cooked the contents of the saucepan had slightly less weight than when we started – as some of the water we began with has evaporated and is no longer registering on our balance. In a similar way, if we consider everything that is produced in the nuclear process, then the mass overall is conserved.
As E = mc2 can be understood to tell us that mass follows the energy (or vice versa) we should expect mass changes (albeit very, very small ones) whenever work is done: when we climb the stairs, or make a cup of tea, or run down a mobile 'phone 'battery' (usually a cell?) – but mass is always conserved when we consider everything involved in any process (such as how the 'phone very, very slightly warms -and so very marginally increases the mass of – the environment).
Despite the scientific principles of conservation of energy and conservation of mass always applying when we make sure we consider everything involved in a process, I have mentioned on this site another example of an astrophysicist suggesting mass can be converted into energy: "an electron and the positron, and you put them together, they would annihilate…they would annihilate into energy" (on a different episode of 'In Our Time': come on Melvyn…we always conserve mass).
Perhaps this is an alternative conception shared by some professional scientists, but I wonder if it sometimes seems preferably to tell the "mass into energy" narrative because it is simpler than having to explain the full details of a process – which is inevitably a more complex story and so will be more difficult for a novice to take in. After all, the "mass into energy" story is likely to seem to fit with a listener's interpretive resources, as E=mc2is such a famous equation that it can be assumed that it will be familiar to most listeners, even if only a minority will have a deep appreciation of how the equivalence works.
Anthropomorphic narratives
In science learning, anthropomorphism is (to borrow a much used metaphor) a double edged sword that can cut both ways. Teachers often find that using narratives that present inanimate entities which are foci of science lessons as if they are sentient beings with social lives and motivations engages learners and triggers mental images that a student can readily remember. So, students may recall learning about what happens at a junction in a circuit in terms of a story about an electron that had to make a decision about which way to go – perhaps she took one branch while her friend tried another? They recall that covalent bonds are the 'sharing' of electrons between atoms, and indeed that atoms want, perhaps even need, to fill their electron shells, and if they manage this they will be happy.
The danger here is that for many students such narratives are not simply useful ways to get them thinking about the science concepts (weakanthropomorphism) but seem quite sufficient as the basis of explanations (stronganthropomorphism) – and so it may become difficult to shift them towards more canonical accounts. They will then write in tests that chemical reactions occur because the atoms want full shells, or that only one electron can be removed from a sodium atom because it then has a full shell. (That is, a force applied to an electron in an electric field is seen as irrelevant compared with the atom's desires. These are genuine examples reflecting what students have said.)
However, there is no doubt that framing scientific accounts within narratives which have elements of human experience as social agent does seem to help make these ideas engaging and accessible. Some such anthropomorphism is explicit, such as when gas molecules (are said to) like to move further apart, and some is more subtle by applying terms which would normally be used in relation to human experiences (not being bothered; chomping; escaping…).
What gravity did next
Consider this statement:
"All stars have the problem of supporting themselves against gravitational collapse, whether that is a star like our sun which is burning hydrogen into helium, and thus providing lots of thermal pressure to stop collapse, or whether it is a white dwarf star, but it does not have any hydrogen to burn, because it is an old dead star, fading away, so it has another method to stop itself collapsing and that is called degeneracy pressure. So, although a white dwarf is very dense, gravity is still trying to pull that white dwarf to be even denser and even denser."
Prof. Mark Sullivan
There is an explicit anthropomorphism here: from the scientific perspective gravity is nottrying to pull the white dwarf to be even denser. Gravity does not try to do anything. Gravity is not a conscious agent with goals that it 'tries' to achieve.
However, there is also a more subtle narrative thread at work – that a star has the problem of supporting itself, and it seems that when its first approach to solving this problem fails, it has a fallback method "to stop itself collapsing". But the star is just a complex system where various forces act and so processes occur. A star is not the kind of entity that can have a problem or enact strategies to achieve goals. Yet, this kind of language seems to naturally communicate abstract ideas though embedding them within an accessible narrative.
Star as moral agents
In the same way, a star is not the type of entity which can carry out immoral acts, but
"A star like our sun will never grow in mass, because it lives by itself in space. But most stars in the universe don't live by themselves, they live in what are called binary systems where you have two stars orbiting each other, rather than just the single star that we have as the sun. They are probably born with different masses, and so they evolve at different speeds and one will become a white dwarf. Now the physics is a bit complicated, but what can happen, is that that white dwarf can steal material from its companion star."
Prof. Mark Sullivan
The meaning here seems very clear, but again there are elements of using an anthropomorphic narrative. For one star to steal material from another star, that material would have to first belong to that other star, and its binary 'partner' would have to deliberately misappropriate that material knowing it belongs to its 'neighbour' (indeed, "companion").
Such a narrative breaks down on analysis. If we were to accept that the matter initially belongs to the first star (leaving aside for the moment what kind of entities can be considered to own property) then given that the material in a star got to be there through mutual gravitational attraction, the only obvious basis for ownership is that that matter has become gravitationally bound as part of that star.
If we have no other justification than that (as in the common aphorism, possession is nine points of the law), then when the material is transferred to another star because its gravitational field gives rise to a net force causing the matter to become gravitationally bound to a different star, then we should simply consider ownership to have changed. There is no theft in a context where ownership simply depends on pulling with the greater force. Despite this, we readily accept an analogy from our more familiar human social context and understand that (in a metaphorical sense) one star has stolen from another!
Actually, theft can only be carried out by moral agents – those who have capacity to intend to deprive others of their property
"A person [sic] is guilty of theft if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it; and "thief" and "steal" shall be construed accordingly"
U.K. Theft Act 1968
Generally, these days (though this was not always so), even non-human animals are seldom considered capable of being responsible for such crimes. Admittedly, the news agency Reuters reported that as recently as 2008 "A Macedonian court convicted a bear of theft and damage for stealing honey from a beekeeper", but this seems to have been less a judgement on the ability of the bear (convicted it its absence) to engage in ethical deliberation, and more a pragmatic move that allowed the bee-keeper to be awarded criminal damages for his losses.
But, according to astronomers, stars are not only involved in the petty larceny of illicitly acquiring gas, but observations of exoplanets suggests some stars may even commit more daring, large-scale, heists,
"fairly small rocky planets two or three times the mass of the earth, in quite tight orbits around their star and you can speculate that they were once giant planets like Jupiter that have had the outer gassy layers blasted off and you are left with the rocky core, or maybe those planets were stolen from another star that got too close"
Prof. Carolin Crawford
A ménage à trois?
And there were other suggestions of anthropomorphism. It is not only stars that "don't live by themselves" in this universe,
"Nickel-56 [56Ni] is what's called an iron peak element, so it lives with iron and cobalt on the periodic table…"
Prof. Mark Sullivan
And, it is not only gravity which seems to have preferences:
"And like Mark has described with electrons not wanting to be squeezed, you have neutron degeneracy pressure. Neutrons don't like to be compressed, at some point they resist it."
Prof. Carolin Crawford
Neither electrons nor neutrons actually have any preferences: but this is an anthropomorphicmetaphor that efficiently communicates a sense of the natural phenomena. 'Resist' originally had an active sense as in taking a stand, but today would not necessarily be understood that way. Wanting and liking (or not wanting and not liking), however, strictly only refer to entities that can have desires and preferences.
Navigating photons
Professor Rees explained why some imploding stars are not seen as very bright stars that fade over years, but rather observed through extremely intense bursts of high energy radiation that fade quickly,
"The energy in the form of ordinary photons, ordinary light, that's arisen in the centre of a supernova, diffuses out and takes weeks to escape, okay, but if the star is spinning, then it will be an oblate spheroid, it will have a minor axis along the spin axis, and so the easy way out is for the radiation not to diffuse through but to find the shortest escape route, which is along the spin axis, and I mention this because gamma ray bursts are … when a supernova occurs but because the original star was sort of flattened there is an easy escape route and all the energy escapes in jets along the spin axis and so instead of it diffusing out over a period of weeks, as it does in a supernova, it comes out in a few seconds."
Prof. Martin Rees
Again, the language used is suggestive. Radiation is not just emitted by the star, but 'escapes' (surely a metaphor?). The phrasing "an easy way out" implies something not being difficult. Inanimate entities like photons do not actually (literally) find anything difficult or easy. Moreover, the radiation might "find the shortest escape route": language that does not reflect a playing out of physical forces but an active search – only a being able to seek can find. Yet, again, the language supports an engaging narrative, 'softening' the rather technical story by subtly reflecting a human quest.
Professor Rees also referred to how,
"when those big stars face a crisis they blow off their outer layers"
Prof. Martin Rees
again using phrasing which seems to present the stars as deliberate actors – they actively "blow off" material when they "face a crisis". A crisis is (or at least was originally) a point where a decision needs to be made. A star does not reach the critical point where it reluctantly decides it needs to shed some material – but rather is subject to changing net forces as the rate of heat generation from nuclear processes starts to decrease.
A sense of anthropomorphic narrative also attaches to Professor Crawford's explanation of how more massive stars process material faster,
"…more massive stars … actually have shorter lifetimes …they have to chomp through their fuel supply so furiously that they exhaust it more rapidly
Prof. Carolin Crawford
'Chomping', a term for vigorous eating (biting, chewing, munching), is here a metaphor, as a star does not eat – as pointed out in the companion piece, nutrition is a characteristics feature of living things, but does not map across to stars even if they are described as being born, living, dying and so forth. To be furious is a human emotional response: stars may process their remaining hydrogen quickly, but there is no fury involved. Again, though, the narrative, perhaps inviting associated mental imagery, communicates a sense of the science.
"…if you have a gas cloud that's been sitting out in space for billions of years and has not bothered to contract because it's been too hot or it's too sparse…"
Prof. Carolin Crawford
This is an interesting example, as Prof. Crawford explicitly explains here that the gas cloud has not contracted because of the low density of material (so weak gravitational forces acting on the particles) and/or the high temperature (so the gas comprises of energetic, so fast moving, particles), so the suggestion that the material cannot be bothered (implication: that the 'cloud' operates as a single entity, and is sentient if perhaps a little lazy) does not stand in place of a scientific explanation, but rather simply seems to be intended to 'soften' (so to speak) the technical nature of the language used.
Analogy
An analogy goes beyond a simile or metaphor because there is some kind of structural mapping to make it explicit in what way or ways the analogue is considered to be like the target concept. 5 (Such as when explaining mass defect in relation to the material lost from the saucepan when cooking rice!)
So, Prof. Rees suggests that scientists can test their theories about star 'life cycles' by observation, even though an individual star only moves through the process over billions of years, and uses an analogy to a more familiar everyday context:
"We can test our theories, not only because we understand the physics, but because we can look at lots of stars. It is rather like if you had never seen a tree before, and you wandered around in a forest for a day, you can infer the life cycles of trees, you'd see saplings and big trees, etcetera. And so even though our lifetime is minuscule compared to the lifetime of a stable star, we can infer the population and life cycles of stars observationally and the theory does corroborate that fairly well."
Prof. Martin Rees
This would seem to make the basis of a good teaching analogy that could be discussed with students and would likely link well with their own experiences.
The other explicit analogy introduced by Prof. Rees is one well-known to physics teachers (sometimes in an ice-skater variant),
"If a contracting cloud has even a tiny little bit of spin, if it is rotating a bit, then as it contracts, then just like the ballerina who pulls in her arms and spins faster, then the contracting cloud will start to spin faster…"
Prof. Martin Rees
Stellar similes
I take the difference between a simile and a metaphor as the presence of an explicit marker (such as '…as…',…like…') to tell the listener/reader that a comparison is being made – so 'the genome is the blueprint for the body' would be a metaphor, where 'the genome is like a blueprint for the body' would be a simile.
As if a black hole cuts itself off
So, when Professor Rees describes how a massive black hole forms, he uses simile (i.e., "…as if were…"),
"So, if a neutron star gets above that mass, then it will compress even further, and will become a black hole – it will go on contracting until it, as it were, cuts itself off from the rest of the universe, leaving a gravitational imprint frozen in the space that's left. It becomes a black hole that things can fall into but not come out."
Prof. Martin Rees
There is an element of anthropomorphic narrative (see above) again here, if we consider the choice of active, rather than passive, phrasing
…as it were, cuts itself off from the rest of the universe, compared with
…as it were, becomes cut off from the rest of the universe
This is presented as something the neutron star itself does ("it will compress…become a black hole – it will go on contracting until it, as it were, cuts itself off…") rather than a process occurring in/to the matter of which it is comprised.
As if galaxies drop over the horizon
Prof. Rees uses another simile, when talking of how the expansion of space means that in time most galaxies will disappear from view,
"All the more distant universe which astronomers like Mark [Sullivan] study, galaxies far away, they will all have expanded their distance from us and in effect disappeared over a sort of horizon and so we just wouldn't see them at all. They'd be too faint, rather like …an inside-out black hole as it were, but in this case they moved so far away that we can't see them any more …"
Prof. Martin Rees
The term horizon, originally referring to the extent of what is in sight as we look across the curved Earth, has become widely used in astronomical contexts where objects cease to be in sight (i.e., the event horizon of a black hole beyond which any light being emitted by an object will not be able to leave {'escape!'} the black hole because of the intense gravitation field), but here Prof. Rees clearly marks out for listeners ("…in effect…a sort of…") that he is making a comparison with the familiar notion of a horizon that we experience here on Earth.
There is another simile here, the reference to the expansion of space leading to an effect "rather like…an inside-out black hole as it were" – but perhaps that comparison would be less useful to a listener new to the topic as it uses a scientific idea rather than an everyday phenomenon as the analogue.
Through a glass onion darkly?
Another simile used by Professor Rees was a references to a "sort of onion skin structure". Now 'onion skin' sometimes refers to the hard, dry, outer material (the 'tunic') usually discarded when preparing the onion for a dish. To a science teacher, however, this is more likely to mean the thin layer of epithelial tissue that can be peeled from the scales inside the bulb. These scales, which are potentially the bases of leaves that can grow if the bulb is planted, are layered in the bulb.
The skin is useful in science lessons as it is a single layer of cells, that is suitable for students to dissect from the onion, and mount for microscopic examination – allowing them to observe the individual cells. There is something at least superficially analogous to this in stars. Observations of the Sun show that convection processes gives rise to structures referred to as convection 'cells'.
Convection 'cells' at the Sun's surface (Source: NASA)Onion skin magnified showing individual epithelial cells (Source: Wikimedia commons)
Yet, when Professor Rees' simile is heard in context, it seems that this is not the focus of the comparison:
"…all the nuclear processes which would occur at different stages in the heavy stars…which have this sort of onion skin structure with the hotter inner layers"
Prof. Martin Rees
Very large stars that have processed much of their hydrogen into helium can be considered to have a layered structure where under different conditions a whole sequence of processes are occurring leading to the formation of successively heavier and heavier elements, and ultimately to a build-up of iron near the centre.
The onion model of the structure of a large star (original image by Taken from Pixabay)
When I heard the reference to the onion, this immediately suggested the layered nature of the onion bulb being like the structure of a star that was carrying out the sequence of processes where the products of one fusion reaction become the raw material for the next. Presumably, my familiarity with the layered model of a star led me to automatically make an association with onions which disregarded the reference to the skin. That is, I had existing 'interpretive resources' to understand why the onion reference was relevant, even though the explicit mention of the skin might make the comparison obscure to someone new to the science.
Metaphors – all the way back up?
Some metaphors can easily be spotted (if someone suggests mitochondria are the power stations of the cell, or a lion is King of the jungle), but if our conceptual systems, and our language, are built by layers of metaphor upon metaphor then actually most metaphors are dead metaphors.
That is, an original metaphor is a creative attempt to make a comparison with something familiar, but once the metaphor is widely taken up, and in time becomes common usage and so a part of standard language, it ceases to act as a metaphor and becomes a literal meaning.
This presumably is what has happened with the adoption of the idea that stars are born, live out their lives, and then die: originally it was a poetic use of language, but now among astronomers it reflects an expanded standard use of terms that were once more restricted (born, live, lifetime, die etc.).
"…Stars dived in blinding skies / Stars die / Blinding skies…" Stars die, but only due to artistic license (Artwork from 'Star's die' by Porcupine Tree, photographer: Chris Kissadjekian)
If you see a standard candle…
When Professor Sullivan refers to a "standard candle", this is now a widely used astronomical notion (in relation to how we estimate distances to distant stars and galaxies that are much too far away to triangulate from parallax as the earth changes its position in the solar system) – but at one time this was used as a figure of speech.
Some figures of speech are created in the moment, but never widely copied and adopted. The astronomical community adopted the 'standard candle' such that it is now an accepted term, even though most young people meeting astronomical ideas for the first time probably have very little direct experience of candles. What might once have seemed a blatantly obvious allusion may now need explaining to the novice.
When Sir Arthur Eddington (famous for collecting observations during an eclipse consistent with predictions from relativity theory about the gravitational 'bending' of starlight) gave a public lecture in 1932, he seems to have assumed that his audience would understand the analogy between an astronomer's 'standard candles' (Cepheid variables) and standard candles they might themselves use!
"If you see a standard candle anywhere and note how bright it appears to you, you can calculate how far off it is; in the same way an astronomer observes his [or her] 'standard candle' in the midst of a nebula, notes its apparent brightness or magnitude, and deduces the distance of the nebula"
Eddington, 1933/1987, pp.7-8
This ongoing development in language means that it may not always be entirely clear which terms are still engaged with as if metaphors and which have now become understood as literal. That is, in considering whether some phrase is a metaphor we can ask two questions:
did the author/speaker intend this as a comparison, or do they consider the term has direct literal meaning?
does the reader/listener understand the term to have a literal meaning, or is it experienced as some novel kind of comparison with another context which has to be related back to the focus?
In the latter case we might also think it is important to distinguish between cases where the audience member can decode the intention of the comparison 'automatically' as part of normal language processing – and cases where they would have to consciously deliberate on the meaning. (In the latter case, the interpretation is likely to disrupt the flow of reading, and when listening could perhaps even require the listener to disengage from the communication such that subsequent speech is missed.)
(Metaphorical?) hosts
So, when Prof. Crawford suggests that
"The supernovae, particularly, are of fundamental importance for the host galaxy…"
Prof. Carolin Crawford
her use of the term 'host' is surely metaphorical (at least for a listener– this term is widely used in the literature of academic astronomy 6). A host offers hospitality for a guest. That does not seem to obviously reflect the relationship between a supernova and the galaxy it is found in and is part of. It is not a guest: rather, in Prof. Sullivan's terms we might suggest that star has 'lived its entire life' in that galaxy – it is its galactic 'home'. Despite this comparison not standing up to much formal analysis, I suspect the metaphor can be automatically processed by anyone with strong familiarity with the concept of a host. Precise alignment may not be a strong criterion for effective metaphors.
Another meaning of host refers to a sacrificial victim (as in the host in the Christian Eucharist) which seems unlikely to be the derivation here, but perhaps fits rather well with Prof. Crawford's point. A supernova too close to earth could potentially destroy the biosphere – an unlikely but not impossible event.
(Metaphorical?) bubbles
Professor Crawford described some of the changes during a supernova,
"You have got your iron core, it collapses down under gravity in less than a second, that kind of leaves the outer layers of the star a little behind, they crash down, bounce on the surface of the core, and then there's a shockwave, that propels all this stellar debris, out into space. So, this is part of the supernova explosion we have been talking about, and it carves out a bubble within the interstellar medium."
Prof. Carolin Crawford
There are a number of places here where everyday terms are applied in an unfamiliar context such as 'core', 'bouncing', 'layers' and 'debris'. But the idea of carving a bubble certainly seems metaphorical, if only because a familiar bubble would have a physical surface, where surely, here, there is no strict interface between discrete regions of gases. But, again, the term offers an accessible image to communicate the process. (And anyone looking at the NASA image above of convection cells in the Sun might well feel that these can be perceived as if bubbles.)
(Metaphorical?) pepper
Similarly, the idea of heavy elements from exploding suns being added to the original hydrogen and helium in the interstellar medium as like adding pepper also offers a strong image,
"…this is the idea of enrichment, you start off with much more primordial hydrogen and helium gas that gets steadily peppered with all these heavy elements…"
Prof. Carolin Crawford
Perhaps 'peppered' is now a dead metaphor, as it is widely used in various contexts unrelated to flavouring food.
(Metaphorical?) imprints
When Professor Rees referred to a neutron star that has become a black hole leaving a "gravitational imprint frozen in the space that's left" this makes good sense as the black hole will not be visible, but its gravitational field will have effects well beyond its event horizon. Yet, one cannot actually make an imprint in space, one needs a suitable material substrate (snow, plater, mud…) to imprint into; and nor has anything been 'frozen' in a literal sense. Indeed, the gravitational field will change as the black hole acquires more material through gravitational capture (and in the very long term loses mass though evaporates Hawking radiation – which is said to cause the black hole to 'evaporate'). So, this is a kind of double metaphor.
(Metaphorical?) blasts and blows
I report above both the idea that rocky planet close to large stars might have derived from 'giant' planets "that have had the outer gassy layers blasted off" and how "big stars…blow off their outer layers". Can stars really blow, or is this based on a metaphor. Blasts usually imply explosions, sudden events, so perhaps these are metaphorical blasts? And it is not just larger stars that engage in blowing off,
"[The sun] will blow off its outer layers and become a red giant, expanding so it will engulf the inner planets, but then the core will settle down to what's called a white dwarf, this is a dead, dense star, about a million times denser than normal stuff…."
Prof. Martin Rees
Metaphors galore!
Perhaps those last examples are not especially convincing – but this reflects a point I made earlier. Language changes over time: it is (metaphorically-speaking) fluid. If language started from giving names to things we can directly point at, then anything we cannot directly point at needs to be labelled in terms of existing words. Most of the terms we use were metaphors at some point, but became literal as the language norms changed.
But society is not a completely homogeneous language community. The requirements of professional discourse in astronomy (or any other specialised field of human activity) drive language modifications in particular regards ahead of general language use. It is not just people in Britain and the United States who are divided by a common language – we all are to some extent. What has become literal meaning for for one person (perhaps a science teacher) may well only be a metaphor to another (a student, say).
After all, when I look up what it is to blow off, I find that the most common contemporary meaning relates to a failure to meet a social obligation or arrangement – I am pretty sure (from the context) that that is not what Professor Rees was suggesting ("…when those big stars face a crisis they [let down] their outer layers".) Once we start looking at texts closely, they seem to be 'loaded' with figures of speech. A planet is not materially constrained in space, yet we understand why an orbit might be considered 'tight'.
In the proceeding quote, the core of a star seems to need no explanation although it presumably derives by analogy with the core of an apple or similar fruit, which itself seems to derive metaphorically form an original meaning of the heart. Again, what is meant by engulf is clear enough although originally it referred to the context of water and the meaning has been metaphorically (or analogously) extended.
The terms red giant and white dwarf clearly derive from metaphor. (Sure, a red giant isgigantic, but then, on any normal scale of human experience, so is a white dwarf.) These terms might mystify someone meeting them for the first time so not already aware they are used to refer to classes of star. This might suggest the value of a completely objective language for discussing science where all terms are tightly (hm, too metaphorical…closely? rigidly? well-) defined, but that would be a project reminiscent of the logical positivist programme in early twentieth century that ultimately proved non-viable. We can only define words with more words, and there are limits to the precision possible with a usable, 'living', language.
Take the "discovery that we are literally made of the ashes of long dead stars". Perhaps, but the term ashes normally refers to the remains of burnt organic material, especially wood, so perhaps we are not literally, but only metaphoricallymade of the ashes of long dead stars. Just as when when Professor Sullivan noted,
"the white dwarf is made of carbon, it's made of oxygen, and the temperature and the pressure in the centre of that white dwarf star can become so extreme, that carbon detonation can occur in the centre of the white dwarf, and that is a runaway thermonuclear reaction – that carbon burns in astronomer speak into more massive elements…"
Prof. Mark Sullivan
Are we stardust, ashes or just waste?
Burning is usually seen in scientific terms as another word for combustion. So, the nuclear fusion, 'burning' "in astronomer speak" of its nuclear 'fuel' in a star represents an extension of the original meaning by analogy with combustion. 9 Material that is deliberately used to maintain a fire is fuel. A furnace is an artefact deliberately built to maintain a high temperature – the nuclear furnace in a star is not an artefact but a naturally occurring system (gravity holds the material in place), but is metaphorically a furnace. A runaway is a fugitive who has absconded – so to describe a thermonuclear reaction (which is not going anywhere in spatial terms) as 'runaway' adopts what was a metaphor. (Astronomers also use the term 'runaway' to label a class of star that seem to be moving especially fast compared with the interstellar medium – a somewhat more direct borrowing of the usual meaning of 'runaway'.)
To consider us to be made from 'nuclear waste' relies on seeing the star-as-nuclear-furnace as analogous to a nuclear pile in a power station. In nuclear power stations we deliberately process fissile material to allow us to generate electrical power: and material is produced as a by-product of this process (that is, it is a direct product of the natural nuclear processes, but a by-product of our purposeful scheme to generate electricity). To consider something waste means making a value judgement.
If the purpose of a star is to shine (a teleological claim) and the fusion of hydrogen is the means to achieve that end, then the material produced in that process which is no longer suitable as 'fuel' can be considered 'waste'. If the universe does not have any purpose(s) for stars then there is no more basis for seeing this material as waste than there is for seeing stars themselves as the waste products of a process that causes diffuse matter to come together into local clumps. That is, this is an anthropocentric perspective that values stars as of more value than either the primordial matter from which they formed, or the 'dead' matter they will evolve into when they no longer shine 'for us'. Nature may not have such favourites! If it has a purpose, then stars seem to only be intermediate steps towards its ultimate end.
What does support the turtle? Surely, it's metaphors all the way down. (Source: Pintrest)
Sources cited:
Eddington, A. (1933/1987). The Expanding Universe. Cambridge: Cambridge University Press.
Lakoff, G., & Johnson, M. (1980). The metaphorical structure of the human conceptual system. Cognitive Science, 4(2), 195-208.
Ulmer, M., Grace, V., Hudson, H., & Schwartz, D. (1972). Upper Limits to the X-Ray Luminosities of Five Supernovae. The Astrophysical Journal, 173, 205.
Notes:
1 It may seem fanciful that we give a specific individual tree a proper name but should a child inherently appreciate that we commonly name individual hamsters (say, or ships, or roads), but not individual trees? 'Major Oak'is a particular named Oak tree in Sherwood Forest, so the idea is not ridiculous. (It is very large, but apparently the name derives from it being described by an author with the army rank of major. Of course, this term for a soldier leading others derives metaphorically from a Latin word meaning bigger, so…)
2 "So how do we bridge between dogs and trees on one hand and electrons and the strong nuclear force on the other (so to speak!)? The answer is we build using analogy and we talk about those constructions using a great deal of metaphor."
We understand what is meant by bridge here in relation to an actual bridge that physically links two places – such as locations on opposite sides of a river or railway line.
There is no actual building up of materials, but we understand how we can 'build' in the abstract by analogy.
These things are not actually at hand, but we make a metaphorical comparison in terms of distinguishing items held in 'opposite' hands. We understand what is meant by a great deal of something abstract by analogy with a great deal of something we can directly experience, e.g., sand, water, etcetera.
Justice personified, on the one hand weighing up the evidence and on the other imposing sanctions
(Image by Sang Hyun Cho from Pixabay)
We construct scientific concepts and models and theories by analogy with how we construct material buildings – we put down foundations then build up brick by brick so that the top of the structure is only very indirectly supported by the ground.
(Image by joffi from Pixabay)
3 A point is a hypothetical, infinitesimally small, location in space, which is not something a person could actually make. The 'point' of an argument is metaphorically like the point of a pencil or spear which is metaphorically an approximation to an actual point. Of course, we (adult members of the English language community) all know what is meant by the point of an argument – but people new to a language (such as young children) have to find this out, without someone holding up the point of an argument for them to learn to recognise.
4 In part, this means linguistic resources. Each individual person has a unique vocabulary, and even though sharing most words with others, often has somewhat unique ranges of application of those words. But it also refers to personal experiences that can be drawn upon (e.g., having cared for an ill relative, having owned a pet, having undertaken part-time work in a hospital pharmacy, having been taken to work by a parent…) and the cultural referents that are commonly discussed in discourse (cultural icons like the Mona Lisa or Beethoven's fifth symphony; familiarity with some popular television show or film; appreciating that Romeo and Juliet were tragic lovers, or that Gandhi is widely considered a moral role model, and so forth.)
"Penny, I'm a physicist. I have a working knowledge of the entire universe and everything it contains."
"Who's Radiohead?"
"I have a working knowledge of the important things in the universe."
Still from 'The Big Bang Theory' (Chuck Lorre Productions / Warner Bros. Television)
The interpretive resources are whatever mental resources are available to help make sense of communication.
5 I am using the term concept in an 'inclusive' sense (Taber, 2019), in that whenever a person can offer a discrimination about whether something is an example of some category, then they hold a concept (vague or detailed; simple or complex; canonical or alternative).
That is, if someone can (beyond straight guesswork) try to answer one of the questions "what is X? ", "is this an example of X?" or "can you suggests an example of X?", then they have a relevant concept – where X could be…
6 The earliest reference to 'host galaxies' I found in a quick search of the scientific literature was from 1972 in a paper which used the term 'host galaxy' 8 times, including,
"We estimated the distances [of observed supernovae]…by four different methods:
(1) Estimating the absolute luminosity of the host galaxy.
(2) Estimating the absolute luminosity of the supernova.
(3) Using the measured redshift of the host galaxy and assuming the Hubble constant H = 75 km (s Mpc)-1 …
(4) Identifying the host galaxy with a cluster of galaxies for which the distance from Earth had already been estimated.
Ulmer, Grace, Hudson & Schwartz, 1972, p.209
The term 'host galaxy' was not introduced or defined in the paper, suggesting that either it was already in common use as a scientific term (and so a dead metaphor within the astronomical community) in 1972 or Ulmer and colleagues assumed it was obvious enough not to need explanation.
7 It should be pointed out that 'In Our Time' is not presented as succession of mini-lectures, or as a tightly scripted programme, but as a conversation between Melvyn as his guests. Of course, there is some level of preparation by those involved, but in adopting a conversational style, avoiding the sense of prepared statements, it is inevitable that a guest's language will sometimes lack the precision of a drafted and much revised account.
8 A supernova may appear as a new star in the sky if it is so far away that the star was not previously detectable, or as a known star quick;y becoming very much brighter.
9 One should be careful in making such equivalences, as in that although we may equate burning with combustion, burning is an everyday ('life world') phenomenon, and combustion is a scientific concept: often our scientific concepts are more precisely defined than the related everyday terms. (Which is why melting has a broader meaning in everyday life {the sugar melts in the hot tea; the stranger melted away into the mist} than it does in science.) But although we might say, as suggested earlier in the text, we have been burned by exposure to the sun's ultraviolet rays, or by contact with a caustic substance, in those contexts we are unlikely to consider our skin as 'fuel' for the process.
