Category: interviewing

What COVID really likes

Researching viral preferences

Keith S. Taber

When I was listening to the radio news I heard a clip of the Rt. Hon. Sajid Javid MP, the U.K. Secretary of State for Health and Social Care, talking about the ongoing response to the COVID pandemic:

Health Secretary Sajid Javid talking on 12th September

"Now that we are entering Autumn and Winter, something that COVID and other viruses, you know, usually like, the prime minister this week will be getting out our plans to manage COVID over the coming few months."

Sajid Javid

So, COVID and other viruses usually like Autumn and Winter (by implication, presumably, in comparison with Spring and Summer).

This got me wondering how we (or Sajid, at least) could know what the COVID virus (i.e., SARS-CoV-2 – severe acute respiratory syndrome coronavirus 2) prefers – what the virus 'likes'. I noticed that Mr Javid offered a modal qualification to his claim: usually. It seemed 'COVID and other viruses' did not always like Autumn and Winter, but usually did.

Yet there was a potential ambiguity here depending how one parsed the claim. Was he suggesting that

[COVID and other viruses]

usually

like Autumn and Winter		orCOVID

[and other viruses usually]

like Autumn and Winter

This might have been clearer in a written text as either

COVID and other viruses usually like Autumn and WinterorCOVID, and other viruses usually, like Autumn and Winter

The second option may seem a little awkward in its phrasing, 1 but then not all viral diseases are more common in the Winter months, and some are considered to be due to 'Summer viruses':

"Adenovirus, human bocavirus (HBoV), parainfluenza virus (PIV), human metapneumovirus (hMPV), and rhinovirus can be detected throughout the year (all-year viruses). Seasonal patterns of PIV are type specific. Epidemics of PIV type 1 (PIV1) and PIV type 3 (PIV3) peak in the fall [Autumn] and spring-summer, respectively. The prevalence of some non-rhinovirus enteroviruses increases in summer (summer viruses)"


Moriyama, Hugentobler & Iwasaki, 2020: 86

Just a couple of days later Mr Javid was being interviewed on the radio, and he made a more limited claim:

Health Secretary Sajid Javid talking on BBC Radio 4's 'Today' programme, 15th September

"…because we know Autumn and Winter, your COVID is going to like that time of year"

Sajid Javid

So, this claim was just about the COVID virus, not viruses more generally, and that we know that COVID is going to like Autumn and Winter. No ambiguity there. But how do we know?

Coming to knowledge

Historically there have been various ways of obtaining knowledge.

  • Divine revelation: where God reveals the knowledge to someone, perhaps through appearing to the chosen one in a dream.
  • Consulting an oracle, or a prophet or some other kind of seer.
  • Intuiting the truth by reflecting on the nature of things using the rational power of the human intellect.
  • Empirical investigation of natural phenomena.

My focus in this blog is related to science, and given that we are talking about public health policy in modern Britain, I would like to think Mr Javid was basing his claim on the latter option. Of course, even empirical methods depend upon some metaphysical assumptions. For example, if one assumes the cosmos has inbuilt connections one might look for evidence in terms of sympathies or correspondences. Perhaps, if the COVID virus was observed closely and looked like a snowflake, that could (in this mindset) be taken as a sign that it liked Winter.

A snowflake – or is it a virus particle?
(Image by Gerd Altmann from Pixabay)

Sympathetic magic

This kind of correspondence, a connection indicated by appearance, was once widely accepted, so that a plant which was thought to resemble some part of the anatomy might be assumed to be an appropriate medicine for diseases or disorders associated with that part of the body.

This is a kind of magic, and might seem a 'primitive' belief to many people today, but such an idea was sensible enough in the context of a common set of underlying beliefs about the nature and purposes of the world, and the place and role of people in that world. One might expect that specific beliefs would soon die out if, for example, the plant shaped like an ear turned out to do nothing for ear ache. Yet, at a time when medical practitioners could offer little effective treatment, and being sent to a hospital was likely to reduce life expectancy, herbal remedies at least often (if not always) did no harm.

Moreover, many herbs do have medicinal properties, and something with a general systemic effect might work as topical medicine (i.e., when applied to a specific site of disease). Add to that, the human susceptibility to confirmation bias (taking more notice of, and giving more weight to, instances that meet our expectations than those which do not) and the placebo effect (where believing we are taking effective medication can sometimes in itself have beneficial effects) and the psychological support offered by spending time with an attentive practitioner with a good 'bedside' manner – and we can easily see how beliefs about treatments may survive limited definitive evidence of effectiveness.

The gold standard of experimental method

Of course, today, we have the means to test such medicines by taking a large representative sample of a population (of ear ache sufferers, or whatever), randomly dividing them into two groups, and using a double-blind (or should that be double-deaf) approach, treat them with the possible medicine or a placebo, without either the patient or the practitioner knowing who was getting which treatment. (The researchers have a way to know of course – or it would difficult to deduce anything from the results.) That is, the randomised control trial (RCT).

Now, I have been very critical of the notion that these kinds of randomised experimental designs should be automatically be seen as the preferred way of testing educational innovations (Taber, 2019) – but in situations where control of variables and 'blinding' is possible, and where randomisation can be applied to samples of well-defined populations, this does deserve to be considered the gold standard. (It is when the assumptions behind a research methodology do not apply that we should have reservations about using it as a strategy for enquiry.)

So can the RCT approach be used to find out if COVID has a preference for certain times of year? I guess this depends on our conceptual framework for the research (e.g., how do we understand what a 'like' actually is) and the theoretical perspective we adopt.

So, for example, behaviourists would suggest that it is not useful to investigate what is going on in someone's mind (perhaps some behaviorists do not even think the mind concept corresponds to anything real) so we should observe behaviours that allow us to make inferences. This has to be done with care. Someone who buys and eats lots of chocolate presumably likes chocolate, and someone who buys and listens to a lot of reggae probably likes reggae, but a person who cries regularly, or someone that stumbles around and has frequent falls, does not necessary like crying, or falling over, respectively.

A viral choice chamber

So, we might think that woodlice prefer damp conditions because we have put a large number of woodlice in choice chambers with different conditions (dry and light, dry and dark, damp and light, damp and dark) and found that there was a statistically significant excess of woodlice settling down in the damp sections of the chamber.

Of course, to infer preferences from behaviour – or even to use the term 'behaviour' – for some kinds of entity is questionable. (To think that woodlice make a choice based on what they 'like' might seem to assume a level of awareness that they perhaps lack?) In a cathode ray tube electrons subject to a magnetic field may be observed (indirectly!) to move to one side of the tube, just as woodlice might congregate in one chamber, but I am not sure I would describe this as electrons liking that part of the tube. I think it can be better explained with concepts such as electrical charge, fields, forces, and momentum.

It is difficult to see how we can do double blind trials to see which season a virus might like, as if the COVID virus really does like Winter, it must surely have a way of knowing when it is Winter (making blinding impossible). In any case, a choice chamber with different sections at different times of the year would require some kind of time portal installed between its sections.

Like electrons, but unlike woodlice, COVID viral particles do not have an active form of transport available to them. Rather, they tend to be sneezed and coughed around and then subject to the breeze, or deposited by contact with surfaces. So I am not sure that observing virus 'behaviour' helps here.

So perhaps a different methodology might be more sensible.

A viral opinion poll

A common approach to find out what people like would be a survey. Surveys can sometimes attract responses from large numbers of respondents, which may seem to give us confidence that they offer authentic accounts of widespread views. However, sample size is perhaps less important than sample representativeness. Imagine carrying out a survey of people's favourite football teams at a game at Stamford Bridge; or undertaking a survey of people's favourite bands as people queued to enter a King Crimson concert! The responses may [sic, almost certainly would] not fully reflect the wider population due to the likely bias in such samples. Would these surveys give reliable results which could be replicated if repeated at the Santiago Bernabeu or at a Marillion concert?

How do we know what 'COVID 'really likes?
(Original Images by OpenClipart-Vectors and Gordon Johnson from Pixabay)

A representative sample of vairants?

This might cause problems with the COVID-19 virus (SARS-CoV-2). What counts as a member of the population – perhaps a viable virus particle? Can we even know how big the population actually is at the time of our survey? The virus is infecting new cells, leading to new virus particles being produced all the time, just as shed particles become non-viable all the time. So we have no reliable knowledge of population numbers.

Moreover, a survey needs a representative sample: do the numbers of people in a sample of a human population reflect the wider population in relevant terms (be that age, gender, level of educational qualifications, earnings, etc.)? There are viral variants leading to COVID-19 infection – and quite a few of them. That is, SARS-CoV-2 is a class with various subgroups. The variants replicate to different extents under particular conditions, and new variants appear from time to time.

So, the population profile is changing rapidly. In recent months in the UK nearly all infections where the variant has been determined are due to the variant VOC-21APR-02 (or B.1.617.2 or Delta) but many people will be infected asymptotically or with mild symptoms and not be tested, and so this likely does not mean that VOC-21APR-02 dominates the SARS-CoV-2 population as a whole to the extent it currently dominates in investigated cases. Assuming otherwise would be like gauging public opinion from the views of those particular people who make themselves salient by attending a protest, e.g.:

"Shock finding – 98% of the population would like to abolish the nuclear arsenal,

according to a [hypothetical] survey taken at the recent Campaign for Nuclear Disarmament march"

In any case, surveys are often fairly blunt instruments as they need to present objectively the same questions to all respondents, and elicit responses in a format that can be readily classified into a discrete number of categories. This is why many questionnaires use Likert type items:

Would you say you like Autumn and Winter:

12345
AlwaysNearly alwaysUsuallySometimesNever

Such 'objective' measures are often considered to avoid the subjective nature of some other types of research. It may seem that responses do not need to be interpreted – but of course this assumes that the researchers and all the respondents understand language the same way (what exactly counts as Autumn and Winter? What does 'like' mean? How is 'usually' understood – 60-80% of the time, or 51-90% of the time or…). We can usually (sic) safely assume that those with strong language competence will have somewhat similar understandings of terms, but we cannot know precisely what survey participants meant by their responses or to what extent they share a meaning for 'usually'.

There are so-called 'qualitative surveys' which eschew this kind of objectivity to get more in-depth engagement with participants. They will usually use interviews where the researcher can establish rapport with respondents and ask them about their thoughts and feelings, observe non-verbal signals such as facial expressions and gestures, and use follow-up questions… However, the greater insight into individuals comes at a cost of smaller samples as these kinds of methods are more resource-intensive.

But perhaps Mr Javid does not actually mean that COVID likes Autumn and Winter?

So, how did the Department of Health & Social Care, or the Health Secretary's scientific advisors, find out that COVID (or the COVID virus) likes Autumn and Winter? The virus does not think, or feel, and it does not have preferences in the way we do. It does not perceive hot or cold, and it does not have a sense of time passing, or of the seasons.2 COVID does not like or dislike anything.

Mr Javid needs to make himself clear to a broad public audience, so he has to avoid too much technical jargon. It is not easy to pitch a presentation for such an audience and be pithy, accurate, and engaging, but it is easy for someone (such as me) to be critical when not having to face this challenge. Cabinet ministers, unlike science teachers, cannot be expected to have skills in communicating complex and abstract scientific ideas in simplified and accessible forms that remain authentic to the science.

It is easy and perhaps convenient to use anthropomorphic language to talk about the virus, and this will likely make the topic seem accessible to listeners, but it is less clear what is actually meant by a virus liking a certain time of year. In teaching the use of anthropomorphic language can be engaging, but it can also come to stand in place of scientific understanding when anthropomorphic statements are simply accepted uncritically at face value. For example, if the science teacher suggests "the atom wants a full shell of electrons" then we should not be surprised that students may think this is a scientific explanation, and that atoms do want to fill their shells. (They do not of course. 3)

Image by Gordon Johnson from Pixabay

Of course Mr Javid's statements cannot be taken as a literal claim about what the virus likes – my point in this posting is to provoke the question of what this might be intended to mean? This is surely intended metaphorically (at least if Mr Javid had thought about his claim critically): perhaps that there is higher incidence of infection or serious illness caused by the COVID virus in the Winter. But by that logic, I guess turkeys really would vote for Christmas (or Thanksgiving) after all.

Typically, some viruses cause more infection in the Winter when people are more likely to mix indoors and when buildings and transport are not well ventilated (both factors being addressed in public health measures and advice in regard to COVID-19). Perhaps 'likes' here simply means that the conditions associated with a higher frequency/population of virus particles occur in Autumn and Winter?

A snowflake.
The conditions suitable for a higher frequency of snowflakes are more common in Winter.
So do snowflakes also 'like' Winter?
(Image by Gerd Altmann from Pixabay)

However, this is some way from assigning 'likes' to the virus. After all, in evolutionary terms, a virus might 'prefer', so to speak, to only be transmitted asymptomatically, as it cannot be in the virus's 'interests', so to speak, to encourage a public health response that will lead to vaccines or measures to limit the mixing of people.

If COVID could like anything (and of course it cannot), I would suggest it would like to go 'under the radar' (another metaphor) and be endemic in a population that was not concerned about it (perhaps doing so little harm it is not even noticed, such that people do not change their behaviours). It would then only 'prefer' a Season to the extent that that time of year brings conditions which allow it to go about its life cycle without attracting attention – from Mr Javid or anyone else.

Keith S. Taber, September 2021

Addendum: 1st December 2021

Déjà vu?

The health secretary was interviewed on 1st December

"…we have always known that when it gets darker, it gets colder, the virus likes that, the flu virus likes that and we should not forget that's still lurking around as well…"

Rt. Hon. Sajid Javid MP, the U.K. Secretary of State for Health and Social Care, interviewed on BBC Radio 4 Today programme, 1st December, 2021
Works cited:
Footnotes:

1. It would also seem to be a generalisation based on the only two Winters that the COVID-19 virus had 'experienced'

2. Strictly I cannot know what it is like to be a virus particle. But a lot of well-established and strongly evidenced scientific principles would be challenged if a virus particle is sentient.

3. Yet this is a VERY common alternative conceptions among school children studying chemistry: The full outer shells explanatory principle

Related reading:

So who's not a clever little virus then?

COVID is like a fire because…

Anthropomorphism in public science discourse

Do nerve signals travel faster than the speed of light?

Keith S. Taber

I have recently posted on the blog about having been viewing some of the court testimony being made available to the public in the State of Minnesota v. Derek Michael Chauvin court case (27-CR-20-12646: State vs. Derek Chauvin).

[Read 'Court TV: science in the media']

Prof. Martin J. Tobin, M.D., Loyola University Chicago Medical Center

I was watching the cross examination of expert witness Dr Martin J. Tobin, Professor of Pulmonary and Critical Care Medicine by defence attorney Eric Nelson, and was intrigued by the following exchange:

Now you talked quite a bit about physics in your direct testimony, agreed?

Yes

And you would agree that physics, or the application of physical forces, is a constantly changing, er, set of circumstances.

I did not catch what you said.

Sure. You would agree with me, would you not, that when you look at the concepts of physics, these things are constantly changing, right?

Yeah, all of science is constantly changing.

Constant! I mean,

Yes.

in milliseconds and nanoseconds, right?

Yes.

And so if I put this much weight [Nelson demonstrating by shifting position] or this much weight [shifting position], all of the formulas [sic] and variations, will change from second to second, from millisecond to millisecond, nanosecond to nanosecond, agreed.

I agree.

Similarly, biology sort of works the same way. Right?

Yes.

My heart beats, my lungs breathe [sic], my brain is sending millions of signals to my body, at all times.

Correct.

Again, even, I mean, faster than the speed of light, right?

Correct.

Millions of signals every nanosecond, right?

Yes.

Day 9. 27-CR-20-12646: State vs. Derek Chauvin

Agreeing – but talking about different things?

The first thing that struck me here concerns what seems to me to be Mr Nelson and Dr Tobin talking at cross-purposes – that neither participant acknowledged (and so perhaps neither were aware of).

I think Nelson is trying to make an argument that the precise state of Mr George Floyd (who's death is at the core of the prosecution of Mr Chauvin) would have been a dynamic matter during the time he was restrained on the ground by three police officers (an argument being made in response to the expert's presentation of testimony suggesting it was possible to posit fairly precise calculations of the forces acting during the episode).

This seems fairly clear from the opening question of the exchange above:

Now you talked quite a bit about physics in your direct testimony, agreed? … And you would agree that physics, or the application of physical forces, is a constantly changing, er, set of circumstances.

However, Dr Tobin does not hear this clearly (there are plexiglass screens between them as COVID precautions, and Nelson acknowledges that he is struggling with his voice by this stage of the trial).

Nelson re-phrases, but actually says something rather different:

You would agree with me, would you not, that when you look at the concepts of physics, these things are constantly changing, right?

['These things' presumably refers to 'the application of physical forces', but if Dr Tobin did not hear Mr Nelson's previous utterance then 'these things' would be taken to be 'the concepts of physics'.]

So, now it is not the forces acting in a real world scenario which are posited to be constantly changing, but the concepts of physics. Dr Tobin's response certainly seems to make most sense if the question is understood in terms of the science itself being in flux:

Yeah, all of science is constantly changing.

Given that context, the following agreement that these changes are occurring "in milliseconds and nanoseconds" seems a little surreal, as it is not quite clear in what sense science is changing on that scale (except in the sense that science is continuing constantly – certainly not in the sense that canonical accounts of concepts shift at that pace: say, in the way Einstein's notions of physics came to replace those of Newton).

In the next exchange the original context Nelson had presented ("the application of physical forces, is … constantly changing") becomes clearer:

And so if I put this much weight [Nelson demonstrating by shifting position] or this much weight [shifting position], all of the formulas and variations, will change from second to second, from millisecond to millisecond, nanosecond to nanosecond, agreed.

I agree.

As a pedantic science teacher I would suggest that it is not the formulae of physics that change, but the values to be substituted into the system of equations derived from them to describe the particular event: but I think the intended meaning is clear. Dr Tobin is a medical expert, not a physicist nor a science teacher, and the two men appear to be agreeing that the precise configurations of forces on a person being restrained will constantly change, which seems reasonable. I guess that is what the jury would take from this.

If my interpretation of this dialogue is correct (and readers may check the footage and see how they understand the exchange) then at one point the expert witness was agreeing with the attorney, but misunderstanding what he was being asked about (how in the real world the forces acting are continuously varying, not how the concepts of science are constantly being developed). Even if I am right, this does not seem problematic here, as the conversation shifted to the intended focus quickly (an example of Bruner's 'constant transnational calibration' perhaps?).

However, this reminds me of interviews with students I have carried out (and others I have listened to undertaken by colleagues), and of classroom episodes where teacher and student are agreeing – but actually are talking at cross purposes. Sometimes it becomes obvious to those involved that this is what has happened – but I wonder how often it goes undetected by either party. (And how often there are later recriminations – "but you said…"!)

Simplifying biology?

The final part of the extract above also caught my attention, as I was not sure what to make of it.

My heart beats, my lungs breathe, my brain is sending millions of signals to my body, at all times.

Correct.

Again, even, I mean, faster than the speed of light, right?

Correct.

Millions of signals every nanosecond, right?

Yes.

How frequently do our brains send out signals?

I am a chemistry and physicist, not a biologist so I was unsure what to make of the millions of signals the brain is sending out to the rest of the body every nanosecond.

I can certainly beleive that perhaps in a working human brain there will be billions of neutrons firing every nanosecond as they 'communicate' with each other. If my brain has something like 100 000 000 000 neurons then that does not seem entirely unreasonable.

But does the brain really send signals to the rest of the body (whether through nerves or by the release of hormones) at a rate of nx106/10-9 s-1 ("millions of signals every nanosecond"), that is,  multiples of 1015 signals per second, as Mr Nelson suggests and Dr Tobin agrees?

Surely not? Dr Tobin is a professor of medicine and a much published expert in his field and should know better than me. But I would need some convincing.

Biological warp-drives

I will need even more convincing that the brain sends signals to the body faster than the speed of light. Both nervous and hormonal communication are many orders of magnitude slower than light speed. The speed of light is still considered to be a practical limit on the motion of massive objects (i.e., anything with mass). Perhaps signals could be sent by quantum entanglement – but that is not how our nervous and endocrine systems function?

If Mr Nelson and Dr Tobin do have good reason to believe that communication of signals in the human body can travel faster than the speed of light then this could be a major breakthrough. Science and technology have made many advances by mimicking, or learning from, features of the structure and function of living things. Perhaps, if we can learn how the body is achieving this impossible feat, warp-drive need not remain just science fiction.

A criminal trial is a very serious matter, and I do not intend these comments to be flippant. I watched the testimony genuinely interested in what the science had to say. The real audience for this exchange was the jury and I wonder what they made of this, if anything. Perhaps it should be seen as poetic language making a general point, and not a technical account to be analysed pedantically. But I think it does raise issues about how science is communicated to non-experts in contexts such as courtrooms.

This was an expert witness for the prosecution (indeed, very much for the prosecution) who was agreeing with the defence counsel on a point strictly contrary to accepted science. If I was on a jury, and an expert made a claim that I knew was contrary to current well-established scientific thinking (whether the earth came into being 10 000 years ago, or the brain sends out signals that travel faster then the speed of light) this would rather undermine my confidence in the rest of their expert testimony.

 

 

 

Single bonds are different to covalent bonds

Single bonds are different to covalent bonds or ionic bonds

Keith S. Taber

Annie was a participant in the Understanding Chemical Bonding project. She was interviewed near the start of her college 'A level' course (equivalent to Y12 of the English school system). Annie was shown, and asked about, a sequence of images representing atoms, molecules and other sub-microscopic structures of the kinds commonl y used in chemistry teaching. She was shown a representation of the resonance between three canonical forms of BF3, sometimes used as away of reflection polar bonding. She had just seen another image representing resonance in the ethanoate ion, and had suggested that it contained a double bond. She had earlier in the interview referred to covalent bonding and ionic bonding, and after introducing the ideas of double bond, suggested that a double bond is different to a covalent bond.

Focal figure (14) presented to Annie

What about diagram 14?…

Oh.

(pause, c.13s)

Seems to be different arrangements. Of the three, or two elements.

Uh hm.

(pause, c.3s)

Which are joined by single bonds.

What, where, what single, what sorry are joined by single bonds?

All the F to the B to the F. Are single bonds they are not double like before. [i.e., a figure discussed earlier in the interview]

So are they covalent bonds? Or ionic bonds, or? Or are single bonds something different again?

Single bonds are different.

This reflected her earlier comment to the effect that a double bond is different to a covalent bond, suggesting that she did not appreciate how covalent bonds are considered to be singular or multiple.

However, as I checked what she was telling me, Annie's account seemed to shift.

They're different to double bonds?

Yeah.

And are they different to covalent bonds?

No 'cause you probably get covalent bonds which are single bonds.

So single bonds, just moments before said to different to covalent bonds, were now 'probably' capable of being covalent. As she continued to answer questions, Annie decided these were 'probably' just alternative terms.

So covalent bonds and single bonds, is that another word for the same thing?

Yeah, probably. But they can probably occur in different, things like in organic you talk about single bonds more than you talk about covalent, and then like in inorganic you talk about covalent bond, more than you talk about single bonding or double bonding.

So you think that maybe inorganic things, like sort of, >> copper iodide or something like that, that would tend to be more concerned with covalent bonds?

< Yeah. < Yeah.

But if you were doing organic things like, I don't know, erm, ethane, >> that's more likely to have single bonds in.

< Yeah. < Yeah.

So single bonds are more likely to occur in carbon compounds.

Yeah.

And covalent bonds are more likely to occur in some other type of compound?

Yeah. Sort of you've got different terminology, like you could probably use single bonds to refer to something in inorganic, but when you are talking about the structures and that, it's easier to talk about single bonds and double bonds, rather than saying that's got a covalent bond or that's got an ionic bond.

Annie's explanation did not seem to be a fully thought-out position. It was not consistent with the way she had earlier reported there being five covalent bonds and one double bond in an ethanoate ion.

It seems likely that in the context of the research interview, where being asked directly about these points, Annie was forced to make explicit the reasons she tended to label particular bonds in specific ways. The interview questions may have acted like Socratic questioning, a kind of scaffolding, leading to new insights. Only in this context did she realise that the single and double bonds her organic chemistry lecturer talked about might actually be referring to the same entities as the covalent bonds her inorganic chemistry lecturer talked about.

It would probably not have occurred to Annie's lecturers (of which, I was one) that she would not realise that single and double bonds were covalent bonds. It may well have been that if she had been taught by the same lecturer in both areas, the tendency to refer to single and multiple bonds in organic compounds (where most bonds were primarily covalent) and to focus on the covalent-ionic dissension in inorganic compounds (where degree of polarity in bonds was a main theme of teaching) would still have lead to the same confusion. Later in the interview, Annie commented that:

if I use ionic or covalent I'm talking about, sort of like a general, bond, but if I use double or single bonds, that's mainly organic, because sort of it represents, sort of the sharing, 'cause like you draw all the molecules out more.

This might be considered an example of fragmentation learning impediment, where a student does not make a link that the teacher is likely to assume is obvious.

How plants get their food to grow and make energy

Respiration produces energy, but photosynthesis produces glucose which produces energy

Keith S. Taber

Image by Frauke Riether from Pixabay 

Mandy was a participant in the Understanding Science Project. When I spoke to her in Y10 (i.e. when she was c.14 year old) she told me that photosynthesis was one of the topics she was studying in science. So I asked her about photosynthesis:

So, photosynthesis. If I knew nothing at all about photosynthesis, how would you explain that to me?

It's how plants get their food to grow and – stuff, and make energy

So how do they make their energy, then?

Well, they make glucose, which has energy in it.

How does the energy get in the glucose?

Erm, I don't know.

It's just there is it?

Yeah, it's just stored energy

I was particularly interested to see if Mandy understood about the role of photosynthesis in plant nutrition and energy metabolism.

Why do you think it is called photosynthesis, because that's a kind of complicated name?

Isn't photo, something to do with light, and they use light to – get the energy.

So how do they do that then?

In the plant they've got chlorophyll which absorbs the light, hm, that sort of thing.

What does it do once it absorbs the light?

Erm.

Does that mean it shines brightly?

No, I , erm – I don't know

Mandy explained that the chlorophyll was in the cells, especially in the plant's leaves. But I was not very clear on whether she had a good understanding of photosynthesis in terms of energy.

Do you make your food?

Not the way plants do.

…

So where does the energy come from in your food then?

It's stored energy.

How did it get in to the food? How was it stored there?

Erm.

[c. 2s pause]

I don't know.

At this point it seemed Mandy was not connecting the energy 'in' food either directly or indirectly with photosynthesis.

Okay. What kind of thing do you like to eat?

Erm, pasta.

Do you think there is any energy value in pasta? Any energy stored in the pasta?

Has lots of carbohydrates, which is energy.

…

So do you think there is energy within the carbohydrate then?

Yeah.

Stored energy.

Yeah.

So how do you think that got there, who stored it?

(laughs) I don't know.

Again, the impression was that Mandy was not linking the energy value of food with photosynthesis. The reference to carbohydrates being energy seemed (given the wider context of the interview) to be imprecise use of language, rather than a genuine alternative conception.

So do you go to like the Co-op and buy a packet of pasta. Or mum does I expect?

Yeah.

Yeah. So do you think, sort of, the Co-op are sort of putting energy in the other end, before they send it down to the shop?

No, it comes from 'cause pasta's made from like flour, and that comes from wheat, and then that uses photosynthesis.

Now it seemed that it was quite clear to Mandy that photosynthesis was responsible for the energy stored in the pasta. It was not clear why she had not suggested this before, but it seemed she could make the connection between the food people eat and photosynthesis. Perhaps (it seems quite likely) she had previously been aware of this and it initially did not 'come to mind', and then at some point during this sequences of questions there was a 'bringing to mind' of the link. Alternatively, it may have been a new insight reached when challenged to respond to the interview questions.

So you don't need to photosynthesise to get energy?

No.

No, how do you get your energy then?

We respire.

Is that different then?

Yeah.

So what's respire then, what do you do when you respire?

We use oxygen to, and glucose to release energy.

Do plants respire?

Yes.

So when do you respire, when you are going to go for a run or something, is that when you respire, when you need the energy?

No, you are respiring all the time.

Mandy suggested that plants mainly respire at night because they are photosynthesising during the day. (Read 'Plants mainly respire at night'.)

So is there any relationship do you think between photosynthesis and respiration?

Erm respiration uses oxygen – and glucose and it produces er carbon dioxide and water, whereas photosynthesis uses carbon dioxide and water, and produces oxygen and glucose.

So it's quite a, quite a strong relationship then?

Yeah.

Yeah, and did you say that energy was involved in that somewhere?

Yeah, in respiration, they produce energy.

What about in photosynthesis, does that produce energy?

That produces glucose, which produces the energy.

I see, so there is no energy involved in the photosynthesis equation, but there is in the glucose?

Yeah.

Respiration does not 'produce' energy of course, but if it had the question about whether photosynthesis also produced energy might have been expected to elicit a response about photosynthesis 'using' energy or something similar, to give the kind of symmetry that would be consistent with conservation of energy (a process and its reverse can not both 'produce' energy). 'Produce' energy might have meant 'release' energy in which case it might be expected the reverse process should 'capture' or 'store' it.

Mandy appreciated the relationship between photosynthetic and respiration in terms of substances, but had an asymmetric notion of how energy was involved.

Mandy appeared to be having difficult appreciating the symmetrical arrangement between photosynthesis and respiration because she was not clear how energy was transformed in photosynthesis and respiration. Although she seemed to have the components of the scientific narrative, she did not seem to fully appreciate how the absorption of light was in effect 'capturing' energy that could be 'stored' in glucose till needed. At this stage in her learning she seemed to have grasped quite a lot of the relevant ideas, but not quite integrated them all coherently.

Higher resistance means less current for the same voltage – but how does that relate to the formula?

Image by Gerd Altmann from Pixabay 

The higher resistance is when there is less current flowing around the circuit when you have the same voltage – but how does that relate to the formula?

Adrian was a participant in the Understanding Science Project. When I interviewed him in Y12 when he was studying Advanced level physics he told me that "We have looked at resistance and conductance and the formulas that go with them" and told me that "Resistance is current over, voltage, I think" although he did not think he could remember formulae. He thought that an ohm was the unit that resistance is measured in, which he suggested "comes from ohm's law which is the…formula that gives you resistance".

Two alternative conceptions

There were two apparent alternative conceptions there. One was that 'Resistance is current over voltage', but as Adrian believed that he was not good at remembering formulae, this would be a conception to which he did not have a high level of commitment. Indeed, on another occasion perhaps he would have offered a different relationship between R, I, and V. I felt that if Adrian had a decent feel for the concepts of electrical resistance, current and voltage then he should be able to appreciate that 'resistance is current over voltage' did not reflect the correct relationship. Adrian was not confident about formulae, but with some suitable leading questioning he might be able to think this through. I describe my attempts to offer this 'scaffolding' below.

The other alternative conception was to conflate two things that were conceptually different: the defining equation for resistance (that R=V/I, by definition so must be true) and Ohm's law that suggests for certain materials under certain conditions, V/I will be found to be constant (that is an empirical relationship that is only true in certain cases). (This is discussed in another post: When is V=IR the formula for Ohm’s law?)

So, I then proceeded to ask Adrian how he would explain resistance to a younger person, and he suggested that resistance is how much something is being slowed down or is stopped going round. After we had talked about that for a while, I brought the discussion back to the formula and the relationship between R, V and I.

Linking qualitative understanding of relating concepts and the mathematical formula

As Adrian considered resistance as slowing down or stopping current I thought he might be able to rationalise how a higher resistance would lead to less current for a particular potential difference ('voltage').

Okay. Let’s say we had, erm, two circuits, and they both have resistance and you wanted to get one amp of current to flow through the circuits, and you had a variable power supply.

Okay.

And the first circuit in order to get one (amp) of current to flow through the circuit.

Yes.

You have to adjust the power supply, until you had 10 volts.

Okay.

So it took 10 volts to get one amp to flow through the circuit. And the second (unclear) the circuit, when you got up to 10 volts, (there is) still a lot less than one amp flowing. You can turn it up to 25 volts, and only when it got to 25 volts did you get one amp to flow through the circuit.

Yes, okay.

In mathematical terms, the resistance of the first circuit is (R = V/I = 10/1 =) 10Ω, and the second is (25/1 =) 25Ω, so the second – the one that requires greater potential difference to drive the same current, has more resistance.

Do you think those two circuits would have resistance?

Erm, (pause, three seconds) Probably yeah.

This was not very convincing, as it should have been clear that as an infinite current was not produced there must be some resistance. However, I continued:

Same resistance?

No because they are not the same circuit, but – it would depend what components you had in your circuit, if you had different resistors in your circuit.

Yeah, I've got different resistors in these two circuits.

Then yes each would have a different resistance.

Can you tell me which one had the bigger resistance? Or can’t you tell me?

No, I can’t do that.

You can’t do it?

No I don’t think so. No.

Adrian's first response, that the circuits would 'probably' have resistance, seemed a little lacking in conviction. His subsequent responses suggested that although he knew there was a formula he did not seem to recognise that if different p.d.s were required to give the same current, this must suggest there was different resistance. Rather he argued from a common sense position that different circuits would be likely to have different components which would lead to them having different resistances. This was a weaker argument, as in principle two different circuits could have the same resistance.

We might say Adrian was applying a reasonable heuristic principle: a rule of thumb to use when definite information was not available: if two circuits have different components, then they likely they have different resistance. But this was not a definitive argument. Here, then, Adrian seemed to be applying general practical knowledge of circuits, but he was not displaying a qualitative feel for what resistance in a circuit was about in term of p.d. and current.

I shifted my approach from discussing different voltages needed to produce the same current, to asking about circuits where the same potential difference would lead to different current flowing:

Okay, let me, let me think of doing it a different way. For the same two circuits, erm, but you got one let's say for example it’s got 10 volts across it to get an amp to flow.

Yeah. So yes okay so the power supply is 10 volts.

Yeah. And the other one also set on 10 volts,

Okay.

but we don’t get an amp flow, we only get about point 4 [0.4] of an amp, something like that, to flow.

Yeah, yeah.

Any idea which has got the high resistance now?

The second would have the higher resistance.

Why do you say that?

Because less erm – There’s less current amps flowing around the circuit erm when you have the same voltage being put into each circuit.

Okay?

Yes.

This time Adrian adopted the kind of logic one would hope a physics student would apply. It was possible that this outcome was less about the different format of the two questions, and simply that Adrian had had time to adjust to thinking about how resistance might be linked to current and voltage. [It is also possible too much information was packed close together in the first attempt, challenging Adrian's working memory capacity, whereas the second attempt fed the information in a way Adrian could better manage.]

You seem pretty sure about that, does that make sense to you?

Yes, it makes sense when you put it like that.

Right, but when I had it the other way, the same current through both, and one required 10 volts and one required 25 volts to get the same current.

Yes.

You did not seem to be too convinced about that way of looking at it.

No. I suppose I have just thought about it more.

Having made progress with the fixed p.d. example, I set Adrian another with constant current:

Yes. So if I get you a different example like that then…let’s say we have two different circuits and they both had a tenth of an amp flowing,

Okay. Yes.

and one of them had 1.5 volt power supply

Okay yes.

and the other one had a two volt power supply

Yeah.

but they have both got point one [0.1] of an amp flowing. Which one has got the high resistance?

Currents the same, I would say they have got different voltages, yeah, so erm (pause, c.6s) probably the (pause, c.2s) the second one. Yeah.

Because?

Because there is more voltage being put in, if you like, to the circuit, and you are getting less current flowing in and therefore resistance must be more to stop the rest of that.

Yes?

I think so, yes.

Does that make sense to you?

Yeah.

So this time, having successfully thought through a constant p.d. example, Adrian successfully worked out that a circuit that needed more p.d. to drive a certain level of current had greater resistance (here 2.0/0.1 = 20Ω) than one that needed a smaller p.d. (i.e. 1.5/0.1 = 15Ω). However, his language revealed a lack of fluency in using the concepts of electricity. He referred to voltage being "put in" to the circuits rather than across them. Perhaps more significantly he referred to their being "less current flowing in" where there was the same current in both hypothetical circuits. It would have been more appropriate to think of there being proportionally less current. He also referred to the greater resistance stopping "the rest" of the current, which seemed to reflect his earlier suggestion that resistance is how much something is being slowed down or is stopped going round.

My purpose in offering Adrian hypothetical examples, each a little 'thought experiment', was to see if they allowed him to reconstruct the formula he could not confidently recall. As he had now established that

greater p.d. is needed when resistance is higher (for a fixed current)

and that

less current flows when resistance is higher (for a fixed p.d.)

he might (perhaps should) have been able to recognise that his suggestion that "resistance is current over, voltage" was inconsistent with these relationships.

Okay and how does that relate to the formula you were just telling me before?

Erm, No idea.

No idea?

Erm (pause, c.2s) once you know the resistance of a circuit you can work out, or once you know any of the, two of the components you can work out, the other one, so.

Yeah, providing you know the equation, when you know which way round the equation is.

Yes providing you can remember the equation.

So can you relate the equation to the explanations you have just given me about which would have the higher resistance?

So if something has got a higher resistance, so (pause, c.2s) so the current flowing round it would be – the resistance times the voltage (pause, c.2s) Is that right? No?

Erm, so the current is resistance time voltage? Are you sure?

No.

So Adrian suggested the formula was "the current flowing round it would be the resistance times the voltage", i.e., I = R × V (rather than I = V /R ), which did not reflect the qualitative relationships he had been telling me about. I had one more attempt at leading him through the logic that might have allowed him to deduce the general form of the formula.

Go back to thinking in terms of resistance.

Okay.

So you reckoned you can work out the resistance in terms of the current and the voltage?

Yes, I think.

Okay, now if we keep, if we keep the voltage the same and we get different currents,

Yes.

Which has, Which has got the higher resistance, the one with more current or the one with less current?

Erm (Pause, c.6s) So, so, if they keep the same voltage.

That’s the way we liked it the first time so.

Okay.

Let’s say we have got the same voltage across two circuits.

Yes.

Different amounts of current.

Yes.

Which one’s got the higher resistance? The one with more current or the one with less current?

The one with less current.

So less current means it must be more resistance?

Yes.

Ok, so if we had to have an equation R=.

Yes.

What’s it going to be, do you think?

Erm 

(pause, c.7s)

R=

(pause, c.3s)

I don’t know. It's too hard.

Whether it really was too hard for Adrian, or simply something he lacked confidence to do, or something he found too difficult being put 'on the spot' in an interview, is difficult to say. However it seems fair to suggest that the kind of shift between qualitative relationships and algebraic representation – that is ubiquitous in studying physics at this level – did not come readily to this advanced level physics student.

I had expected my use of leading (Socratic) questioning would provide a 'scaffold' to help Adrian appreciate he had misremembered "resistance is current over, voltage, I think", and was somewhat disappointed that I had failed.

'In my head, son' – mind reading commentators

Keith S. Taber

*

"Tim Howard is a little frustrated with himself that it wasn't a tidier save, because he feels he ought to have done better with the first attempt."

Thus claimed the commentator on the television highlights programme Match of the Day (BBC) commenting on the association football (soccer) match Everton vs. Spurs on May 25th 2015.  

It was not a claim that was obviously contradicted by the footage being shown, but inevitably my reaction (as someone who teaches research methods to students) was 'how do you know?" The goalkeeper was busy playing a game of football, some distance from the commentator, and there was no obvious conversation between them. The answer of course is that the commentator was a mind reader who knew what someone else was thinking and feeling.

This is not so strange, as we are all mind readers – or at least we commonly make statements about the thoughts, attitude, feels, beliefs etc. of others, based on their past or present behaviour, subtle body language, facial expressions and/or the context of their current predicament.

Of course, that is not strictly mind reading, as minds are not visible. But part of normal human development is acquiring a 'theory of mind' that allows us to draw inferences about the thoughts and feelings of others – the internal subjective experiences of others – drawing upon our own feelings and thoughts as a model. In everyday life, this ability is essential to normal social functioning – even if we do not always get it right. Yet we become so used to relying upon these skills that public commentators (well, a sports commentator here) feel no discomfort in not only interpreting the play, but the feelings and thoughts of the players they are observing.

A large part of the kind of educational research that I tend to be involved in is very similar to this – it involves using available evidence to make inferences about what others think and feel. [There are many examples in the blog posts on this site.]  Sometimes we have very strong evidence (what people tell us about their thoughts and feelings) but even then this is indirect evidence – we can never actually see another mind at work (1). We do not "see the cogs moving", even if we may like to talk as though we do.

In everyday life we forgive the kinds of under-determined claims made by sports commentators, and may not even notice when they draw such inferences and question what support their claims have. Sadly this seems to be a human quality that we often take for granted a little too much. A great deal of the research literature in science education is written as though research offers definite results about students' conceptions (and misconceptions) and whether or not they know something or understand it – as though such matters are simple, binary, and readily detected (1). Yet research actually suggests this is far from the case (2).

Research that explores students' thinking and learning is actually very challenging, and is in effect a enterprise to build and test models rather than uncover simple truths. I suspect quite a bit of the disagreement about the nature of student thinking in the science education research literature is down to researchers who forget that even if people are mind readers in everyday life, they must become careful and self-critical model builders when they are seeking to make claims presented as research (1).

References:

Taber, K. S. (2013). Modelling Learners and Learning in Science Education: Developing representations of concepts, conceptual structure and conceptual change to inform teaching and research. Dordrecht: Springer.

(2) Taber, K. S. (2014). Student Thinking and Learning in Science: Perspectives on the nature and development of learners' ideas. New York: Routledge.

* Previously published at http://people.ds.cam.ac.uk/kst24/science-education-research: 25th May 2015

Covalent bonding is sharing electrons

It's covalent bonding where the electrons are shared to create a full outer shell

Keith S. Taber

Brian was a participant in the Understanding Chemical Bonding project. He was interviewed during the first year of his college 'A level' course (equivalent to Y12 of the English school system). Brian was shown, and asked about, a sequence of images representing atoms, molecules and other sub-microscopic structures of the kinds commonly used in chemistry teaching. He was shown a simple representation of a covalent molecule:

Focal figure ('2') presented to Brian

Any idea what that's meant to be, number 2?

Hydrogen molecule.

Why, how do you recognise that as being a hydrogen molecule?

Because there's two atoms with one electron in each shell.

Uh hm. Er, what, what's going on here, in this region here, where these lines seem to meet?

Bonding.

That's bonding. So there's some sort of bonding there is there?

Yeah.

Can you tell me anything about that bonding?

It's covalent bonding.

So, so what's covalent bonding, then?

The electrons are shared to create a full outer shell.

Okay, so that's an example of covalent bonding, so can you tell me how many bonds there are there?

One.

There's one covalent bond?

Yeah.

Right, what exactly is a covalent bond?

It's where electrons are shared, almost, roughly equally, between the two atoms.

So that's what we'd call a covalent bond?

Yeah.

So according to Brian, covalent bonding is where "the electrons are shared to create a full outer shell". The idea that a covalent bond is the sharing of electrons to allow atoms to obtain full electron shells is a very common way of discussing covalent bonding, drawing upon the full shells explanatory principle, where a 'need' for completing electron shells is seen as the impetus for bonding, reactions, ion formation etc. This principle is the basis of a common alternative conceptual framework, the octet rule framework.

For some students, such ideas are the extent of their ways of discussing bonding phenomena. However, despite Brian defining the covalent bond in this way, continued questioning revealed that he was able to think about the bond in terms of physical interactions

Okay. And why do they, why do these two atoms stay stuck together like that? Why don't they just pull apart?

Because of the bond.

So how does the bond do that?

(Pause, c.13s)

Is it by electrostatic forces?

Is it – so how do you think that works then?

I'm not sure.

The long pause suggests that Brian did not have a ready formed response for such a question. It seems here that 'electrostatic forces' is little more than a guess, if perhaps an informed guess because charges and forces had features in chemistry. A pause of about 13 seconds is quite a lacuna in a conversation. In a classroom context teachers are advised to give students thinking time rather than expecting (or accepting) immediate responses. Yet, in many classrooms, 13 seconds of 'dead air' (to borrow a phrase from broadcasting) from the teacher night be taken as an invitation to retune attention to another station.

Even in an interview situation the interviewer's instinct may be to move on to a another question, but in situations where a researcher is confident that waiting is not stressful to the participant, it is sometimes productive to give thinking time.

Another issue relating to interviewing is the use of 'leading questions'. Teachers as interviewers sometimes slip between researcher and teacher roles, and may be tempted to teach rather than explore thinking.

Yet, the very act of interviewing is an intervention in the learners' thinking, in that whatever an interviewer tells us is in the context of the conversation set up by the interviewer, and the participant may have ideas they would not have done without that particular context. In any case, learning is not generally a once off event, as school learning relies on physiological process long after the initial teaching event to consolidate learning, and this is supported by 'revision'. Each time a memory is reactivated it is strengthened (and potentially changed).

So the research interview is a learning experience no matter how careful the researcher is. Therefore the idea of leading questions is much more nuanced that a binary distinction between those questions which are leading and those that are not. So rather than completely avoiding leading questions, the researcher should (a) use open-ended questions initially to best understand the ideas the learner most easily beings to mind; (b) be aware of the degree of 'scaffolding' that Socratic questioning can contribute to the construction of a learners' answer. [Read about the idea of scaffolding learning here.] The interview continued:

Can you see anything there that would give rise to electrostatic forces?

The electrons.

Right so the electrons, they're charged are they?

Yeah. Negatively.

Negatively charged – anything else?

(Pause, c.8s)

The protons in the nucleus are positively charged.

Uh hm. And so would that give rise to any electronic interactions?

Yeah.

So where would there be, sort of any kind of, any kind of force involved here is there?

By the bond.

So where would there be force, can you show me where there would be force?

By the, in the bond, down here.

So the force is localised in there, is it?

The erm, protons would be repelling each other, they'd be attracted by the electrons, so they're keep them at a set distance.

It seemed that Brian could discuss the bond as due to electrical interactions, although his initial ('instinctive') response was to explain the bond in terms of electrons shared to fill electron shells. Although the researcher channelled Brian to think about the potential source of any electrical interactions, this was only after Brian had himself conjectured the role of 'electrostatic forces.'

Often students learn to 'explain' bonds as electron sharing in school science (although arguably this is a rather limited form of explanation), and this becomes a habitual way of talking and thinking by the time they progress to college level study.