heating - Science-Education-Research

A Christmas miracle – magic physics powers new heater designs

Keith S. Taber

Looking to check out some music videos on YouTube, and being presented with irrelevant advertisements, I was amazed to learn of a revolutionary new type of electrical heater that can potentially offer consumers vast savings on their electricity bill. Revolutionary, as the inventor, a disgraced London student, seems to have rewritten the laws of physics.

He made a special device that creates a perpetual heating loop,

Revolutionary design: "a perpetual heating loop" (a coil of wire that can be left connected to a power supply?)

Warning. The copyright in the images included here does not belong to me. I think much the video looks like it uses stock footage, but if not, and IF the company behind this product believes they can genuinely support their claims as reported here, they may get in touch to explain why I am misguided.

I generally look to respect copyright in other's work, but I believe it is in the public interest to call out attempts to scam people through misrepresenting science in material in the public domain.

The revolutionary new design of heater is a small plug-in device which can heat up a room very quickly, and moreover it is so efficient that it does not waste energy – like those other more traditional types of heaters some people might still be using.

This technological advance:

can heat a home in 90 seconds
can save a householder thousands of pounds a year
"can warm any space at 90% less cost than conventional heating methods"
avoids any waste: "by reusing the heat it produces, so none of it is wasted"
on testing, it warmed university classrooms "from 10˚C to 21˚C in only 2 minutes"
uses "89% less energy" than regular heating systems

Wow. If not too good to be true, that would certainly help with the climate crisis by reducing electricity demands.

What is the new technology?

The video advertising this new type of heater offer some clues to its design. It begins by illustrating the "trick" which can "heat your home in 90 seconds" and "save thousands of pounds" off the Winter heating bill:

So, it seems you need to get some tea lights, and place them under a large inverted ceramic flower pot? I am pretty sure that's not going to do the 'trick'. Perhaps this was meant as some kind of metaphor…?

Reinstate Jason!

The video explains how 'Jason' "a clever student from UK, London University" creates the new type of heater because the University heating system was not functioning properly. He designed the new heater to support his classmates who were having to work in rooms at 10˚C.

When Jason refused to earn a fortune from his invention by selling the rights, the University responded within three days by expelling him. ¹

His professor even predicted tat Jason was destined to make history.

Jason's professor thought his idea was revolutionary (but he may not be that up to date in his subject knowledge – most of the scientific community adopted metric units decades ago ²)

Apparently Jason achieved this scientific breakthrough by 'reverse-engineering' a standard heater. Presumably the available text books did not explain the physics of heaters (in essence, you connect (i) a piece of conducting material that can withstand heating and that has suitable resistance, to (ii) a power supply); so he had take apart heaters to find out how they worked.

he cleverly figured out how to reverse engineer basic air heater.

Here he seems to be drawing up the specifications for his new design, helped by a sophisticated paper model.

just destroyed the billion pounds heating industry by innovating a device

The video shows how Jason studied circuit components called 'resistors' and found out how to read those little coloured lines on them (as children do in UK schools).

So what was revolutionary about the physics?

Of course, the manufacturers do not want to give away too many commercial secrets (even if Jason had nobler instincts), but the video does offer some clues.

Induction heating

One technique shown in the film is described as "a special device that creates a perpetual heating loop".

The special device illustrated seems to be a coil of thick copper wire, able to pass a large alternating current, which is heating a metal rod 'by induction'.

This works because the coil produces a large constantly changing magnetic field, which induces a changing e.m.f. in the rod. Now this technique only produces heating in an electrical conductor as the magnetic field cannot transfer energy to an insulator, such as air (which is not substantially influenced by the magnetic field). It seems Jason's genius must have been to somehow produce heating of ordinary air by this method. That would be the kind of breakthrough reflecting new physics deserving of a Nobel prize!

The dual Thomson effects

My ageing hearing told me that Jason's revolutionary design used the Joule-Thomson effect. This surprised me a little, as to my mind this technique would produce cooling, not heating. This effect can be experienced in everyday effects – such as in the material propelled from an aerosol can which often feels cold, or when noting the cold air passing out of the valve of a tyre being quickly deflated.

Energy is always conserved in all processes. The conservation of energy is one of the most fundamental principles in science, and is generally believed to be universal in its application. (Thus my annoyance at how the English National Curriculum includes a logically flawed reference to it.) When a compressed gas (such as in the tyre) is allowed to expand through a small opening it does work pushing back the surrounding air, and the temperature drops by a corresponding amount. ³

So, I was mystified at how an effect that usually produced cooling here gives the opposite effect. But then I spotted (from the kindly provided subtitles) that I (or else, the person making the subtitles?) had misheard. It seems Jason was using a different effect: 'dual Thomson' physics.

Jason made it work better, using a dual Thomson physics

I have to confess to not being familiar with 'dual Thomson' physics. Indeed I only found a handful of references on the www through an internet search, and these referred to specialised instruments designed to detect ion velocities in high energy physics research.

I am not sure what that has to do with plug-in wall heaters, and I am pretty sure that that was not what was illustrated in the accompanying footage.

Testing the new design

A powerful device?

According to the video being pushed at viewers by YouTube, Jason "took this amazing gadget to the University and the outcomes were fantastic" where "classrooms went from 10˚C to 21˚C in only 2 minutes".

Before and after – the small device heated a classroom 11˚C in 12o seconds. Hm. (Move the slider to see the images)

classrooms went from 10˚C to 21˚C in only 2 minutes. — Before and after – the small device heated a classroom 11˚C in 12o seconds. Hm. (Move the slider to see the images)

Now that would be pretty impressive, as any lecturer who has arrived in a cold teaching room and then dragged in the electric heater from their office would know (I write from experience).

We are not told the size of the room used in this supposed trial but a lecture room would be something of the order of a thousand cubic metres. If we assume that the heater transfers all of its energy to the air in the room (and that in the short time it is used, none of this heat is lost to outside, or warms up anything else in the room – like the furnishings or the walls or ceilings – or the people who were feeling too cold) then we can calculate the energy needed, and so the power of the heater. My-back-of-the-envelope calculation suggests this would be about 100 kW. ⁴

this innovation swiftly warms rooms using minimal electricity, efficiently

Now I am not going to claim that a hundred kilowatts heater cannot be made, but I am prepared to suggest that no technology available today could safely get near, anywhere near, this power rating with this scale of device.

Larger heaters designed for industrial use are available rated for a few kilowatts, but a 100 kW plug-in heater for domestic use seems fantasy. (Especially as "You can move it around without worrying about burning yourself" according to the website.)

Am I wrong? TechTrends, the website selling the devices (sorry, independently assessing, 😉, 😉, the devices and telling us where to buy them), does not seem to offer any details on this testing, so I assume it was not carried out by competent investigators and reported in a peer reviewed journal. If indeed, given the non-viability of the claim, it really took place. Anyone reading this form TechTrends – if I am wrong please enlighten us? (Comments welcome below.)

Greater efficiency?

We are asked to accept this magical outcome because the device is so energy efficient (that in itself I believe – I expect an electric heater to be very efficient), compared with standard technology. The video claims that the new heater "used 89% less energy" than "regular heating systems". That is clearly nothing other than an outright lie!

What's even more impressive is that it used 89% less energy — Feel the difference – almost 90% apparently (Move the slider to see the images)

compared to regular heating systems. — Feel the difference – almost 90% apparently (Move the slider to see the images)

Many machines are inefficient in the sense that the energy input does not match the desired work output as some energy is 'lost' or perhaps better 'diverted'. Now energy is always conserved, so this means that, say, 100 Joules of energy are 'taken' from some supply to power some activity, but perhaps only 6oJ does what we intend (so in this case, 60% efficiency) and the other 40J has some other effect.

A key idea in thermodynamics is that engines have an inherent limit to efficiency. A car engine exhausting into the atmosphere well above absolute zero (at around 300K rather than 0K) will necessarily only direct a fraction of the energy sourced into the desired locomotion. Achieving higher temperatures in the engine (a technical challenge) can improve what is possible; but only releasing exhaust gases at 0K would make 100% efficiency even theoretically possible. So, is it feasible that normal electrical heaters would be so inefficient?

Filament lamps are only inefficient in the Summer

…or…

Why would anyone manufacture a light bulb completely encased in a solid metal shade?

The notion that a standard electric heater might be no more than 11% efficient might not sound too unlikely to some people watching these commercials as they wait for their music videos (or cats juggling, or whatever their taste may be). One reason filament lamps have been phased out is because they were notoriously inefficient – indeed, 11% efficiency is the kind of figure that was sometimes quoted. A 100 W filament lamp might only be generating visible light at around 11W, which seems quite a waste (especially as the utility company will be billing for all 100W).

I have always considered such lamps to be inefficient in the Summer, but that this is less of an issue in the Winter. That's because that other 89W will be heating up the room – unhelpful or even problematic in Summer, but perhaps acceptable in Winter when we are deliberately heating the rooms anyway. Does it matter if a little more of your heating comes from the light bulbs and a little less from the 'heaters'.

Indeed, when I was a child, before the days when most people had central heating, we used to have a device that was basically a light bulb inside a big metal shield. When turned on, it emitted no light. The bulb did, of course, but not the device. These were used on Winter evenings as bed warmers to avoid getting into a very cold bed. The lamp may have given out 11% light, but it all ultimately got absorbed into the metal and contributed to the heat transfer from filament to bed warmer and so onto the bedding. ⁵

Generally, energy inefficiencies in machines involve energy released as heat that goes to make molecules move about a bit faster on average rather than going where intended to do useful jobs. We might think of heat (or strictly, the dispersed thermal energy of matter, that heat leads to) as the lowest quality form of energy, that all other forms of energy are ultimately, eventually, degraded into.

This unintended 'heat leakage' may be an issue in lamps and motors and televisions and many other devices – but clearly not in heaters.

The same old hot air…

The video suggests one feature of the revolutionary new design is that instead of only heating cold air, the promoted device is able to recycle warm air to minimise waste. What could this mean?

HeatFlow's heating ability surpasses those of any standard system,

recycling warm air to minimize energy waste,

Now if you take an electric heater out into the garden on a cold day when there is a breeze, then it is quite likely that the air that passes through the heater will be blown away quite quickly, and so the heater is always heating air from the same ambient starting point. That would be a bit of a waste. (Hint: do not use an electric heater to keep you warm in the garden – put on warm clothes or move around instead).

Inside a well insulated room, the air that is passing through the heater will soon already have been warmed, so the heater can achieve a higher room temperature for the same power input (compared with when it is operating in your garden, that is). I do not think any reasonable reading of 'standard system' for home heating would not "recycle warm air" rather that continuously heating only cold air, so to my reading this is simply a clear lie.

Some made up numbers from the website 'reviewing' (actually, promoting) the device

90% less cost to the householder?

I therefore consider the claim that the new design of heater "can warm any space at 90% less cost than conventional heating methods" is also a simple lie. Your standard home plug-in heater might not be as well designed, and may have some flaws, but it will not be converting 89 0r 90% of the energy supply into something other than heat. Inefficient machines produce heat instead of other (generally more useful) forms of output.

that can warm any space at 90% less cost tan conventional heating methods.

No, it cannot.

Not unless we've had some basic physics completely wrong for a long time and no one had noticed.

As has been often pointed pointed out, any claim that begins "in fact…" should be treated suspiciously. There is no logical difference between writing

"these claims are inconsistent with the laws of physics", and
"in fact, these claims are inconsistent with the laws of physics"

'In fact' tends to be used rhetorically when what is being said might of itself not seem a very convincing 'fact', and could otherwise be surprising, as in,

"in fact, Albert Einstein never actually found physics interesting"

In fact, it has been proven to be 97% more cost effective

In fact, this is another lie.

The video directs readers to what seems at first sight to be a consumer website praising the new heaters, although they've dropped the story about poor, mistreated Jason,

"This simple but rather genius concept was developed in 2019 by a group of electrical engineers from the EVI (Electric Vehicle Industry)."

There seem to be at least two versions directing to the same basic copy promoting 'EcoWell' and 'HeatFlow' on different webpages. Some customers (such as a 'Daniel Walker') seem to have even sought out both designs, presumably to match their decor in different rooms?

The web-pages do not repeat the more obviously fraudulent claims, but rather seem to suggest the heater is going to save money by pointing out how much heat produced by a domestic heating system is leaving the home. This is important, but it is worth n0oting that (assuming that a house can never have perfect thermal insulation) then when the home has reached a constant temperature (and the external temperature is not changing), the amount of heat being lost to the environment matches that produced by the heaters. That is, 100% of the energy being used for heating is being transferred to the outside. It is important to try to slow that rate, but all heating systems, "leak energy, warming up basements and underground lines", not just those that are "outdated and inefficient" as the TechTrends website implies.

It still claims that "99.8% efficiency ensures all your electricity gets turned into heat, saving you thousands" (where any heater will be highly efficient at producing heat – the issue is how it is distributed), but acknowledges.

"One HeatFlow heater can heat up a room up to 12 square meters. Depending on your needs, you might want to purchase several heaters for continuous warmth in all rooms or keep one to bring with you where you need it the most."

"One EcoWell heater can heat up a room up to 12 square meters. Depending on your needs…"

(The EcoWell design looks very similar to an alternative available from a well-established and reputable manufacturer selling their product on Amazon at £20 when I checked today. Whereas TrechTrends tells readers that with the half price discount "At the moment of writing this review, you can get EcoWell[*] for just £49.99!" [* or HeatFlow if you prefer the tiny coal fireplace look]

So, if you stop heating the house, and just have one single plug-in device that you move around to the room that you are going to be occupying, it will save money on your energy bills. But that will not work if you like frequently moving between rooms in your house, or have a family that like some privacy. (Of course, you can save even more money on your bills by wearing a good many layers of clothing and not using any heaters. )

Still, the website shows there have been many favourable customers' comments, which I rather spoiled yesterday with my own cynical offering:

But that was yesterday, and checking back today I was un-amazed to find my comment wiped. In any case, there is an acknowledgement showing the site is an advert, and the photos are of 'models' not real purchasers:

But it is presented in faint text on a black background seemingly designed to make sure it is not easily noticed ⁶ .

There is of course a special price if you buy now within 24 hours…

As there was yesterday.

Does it matter?

So these advertisements contain some very misleading 'bad science' (or, perhaps – as the claims are inconsistent with well-studied science – magical claims). Misinformation like this is is common in the post-truth age – but here it is masquerading as engineering and physics.

Anyone who has been to school and benefited from science education should not be taken in by the sillier claims about this new design of heater. They may be very useful, compact, convenient, and perhaps even powerful-for-their-size heaters. But the more extreme claims being made are lies, contrary to basic physics.

They cannot heat a classroom in 2 minutes. They are not 97% more cost effective. They will not save people thousands of pounds if used to replace other plug-in heaters. They do not use induction (or tea lights) to heat the air or dual Thomson physics. And although they recycle hot air, so does every other type of room heater. They may well be over 99% efficient, but that's because heat is the lowest grade of energy and so increasing machine efficiency is about avoiding 'high grade' energy being reduced to heat. The claim here is like claiming your teenager is better than the standard model because it can turn an organised bedroom into arbitrarily organised chaos – as if that was a rare quality, given that most teenagers are only ever able to mess up part of a room.

The video is in breach of UK law and YouTube should have done due diligence before accepting advertising money for such deliberately dishonest films. I feel somewhat offended that YouTube would think that an educated person would fall for this – but presumably plenty do. If people are listening to/watching this nonsense and not spotting a problem, then science education has not done a very good job. This kind of scam relies on low levels of scientific literacy.

But, I suspect these companies are getting plenty of sales from their dishonest advertising as in October 2022 I wrote to the Advertising Standards Authority (ASA) to complain about very similar adverts:

"Brand/product: AlphaHeater or Elite Heat

Your complaint: After watching a football match on you tube there was a misleading video, which directed viewers to a misleading website. The video claimed that a revolutionary new heater using jet engine technology would heat a room "using 90% less energy" (screen shot below). This is nonsense (I am a Chartered Physicist, Fellow of the Institute of Physics: heat is the lowest quality form of heat, so (unlike say the working of a motor) a heater cannot be produced so much more more efficiently.). The website was pretending to be an independent review (HeatReviewGuide) of the heater but had dummy links and was only advertising that product (see below). …
Acknowledgement of complaint: October 2022

seems familiar?

The ASA replied

"Thank you for contacting the Advertising Standards Authority (ASA) about ads online for this heating device and for your patience while your complaint was considered.

We acknowledge your concern about this ad and so we have put an alert out to have it taken down through our ASA Scam Ad Alert System. We will share the details of this ad with our network of key industry partners, including all the major social media platforms and ad networks operating in the UK, so that the content is taken down and to help stop similar ads appearing in future."
Outcome of compliant: November 2022

I guess criminals behind these scams respond to this regulation of advertisements by changing the name or other minor details of their products, and then just carrying on. Time for another message to the ASA?

Merry Christmas everyone.

Notes

¹ Even if we believe that Universities still readily expel fee-paying 'customers' for the most vile of offences, and even if we think that refusing to become a billionaire amounts to grounds for such an expulsion (why?) – the idea that a university could act in three days on a student disciplinary matter and follow due process does not ring true. (I know from personal experience there are plenty of people in universities who are prepared to ignore principles of natural justice, but luckily the institutions themselves have careful and balanced procedures to protect members from false and malicious claims). Jason could always have got his University's Enterprise department to help him arrange the commercialisation of the design, and then signed over any personal interests to generate income for a charitable trust.

² I am assuming that psi means pounds per square inch. The scientific units are pascals (that is newtons per square metre) which were already been taught in school when I was a pupil half a century ago.

³Temperature is NOT the same as heat, of course, but a certain temperature change in a sample of a substance involves the transfer of a related amount of energy that for a characterised material can be calculated (heat = product of mass by specific heat capacity by temperature change; 𝚫H = mc𝛉).

⁴I used:

The density of air is about 1200 grammes per cubic metre
the specific heat capacity of air is about 1 Jg^-1K^-1
power = energy transferred / time [= 120s]

⁵ We usually think of light and heat as discrete. But heating is energy transferred due to a difference in temperature: so when radiation is emitted by a hot body and absorbed by a colder one it counts as heat, even if it is light. So heat is not necessary light, but light often counts as heat. As they say, there's often 'more heat than light'.

⁶ Just in case you are finding the text difficult to make out, it reads:

"THIS IS AN ADVERTISEMENT AND NOT AN ACTUAL NEWS ARTICLE, BLOG, OR CONSUMER PROTECTION UPDATE

ADVERTISING DISCLOSURE: THIS WEBSITE AND THE PRODUCTS & SERVICES REFERRED TO ON THE SITE ARE ADVERTISING MARKETPLACES. THIS WEBSITE IS AN ADVERTISEMENT AND NOT A NEWS PUBLICATION. ANY PHOTOGRAPHS OF PERSONS USED ON THIS SITE ARE MODELS. THE OWNER OF THIS SITE AND OF THE PRODUCTS AND SERVICES REFERRED TO ON THIS SITE ONLY PROVIDES A SERVICE WHERE CONSUMERS CAN OBTAIN AND COMPARE."

The earth's one long-term objective

Scientist reveals what the earth has been trying to do

Keith S. Taber

Seismology – the study of the earth letting off steam? (Image by ELG21 from Pixabay)

"the earth has one objective, it has had one objective for four and half billion years, and that's…"

In our time

'In Our Time' is an often fascinating radio programme (and podcast) where Melvyn Bragg gets three scholars from a field to explain some topic to a general audience.

Imagine young Melvyn interrupting a physics teacher's careful exposition of why pV = ¹/₃nmc² by asking how the gas molecules came to be moving in the first place.

The programme covers various aspects of culture.

I am not sure if the reason that I sometimes find the science episodes seem a little less erudite than those in the the other categories is:

a) Melvyn is more of an arts person, so operates at a different level in different topics;
b) I am more of a science person, so more likely to be impressed by learning new things in non-science topics; and to spot simplifications, over-generalisations, and so forth, in science topics.
c) A focus in recent years on the importance of the public understanding of science and science communication means that scientists may (often, not always) be better prepared and skilled at pitching difficult topics for a general audience.
d) Topics from subjects like history and literature are easier to talk about to a general audience than many science topics which are often highly conceptual and technical.

Anyway, today I did learn something from the episode on seismology ("Melvyn Bragg and guests discuss how the study of earthquakes helps reveal Earth's secrets [sic]"). I was told what the earth had been up to for the last four and half billion years…

Seismology: Where does this energy come from?

Quite early in the discussion Melvyn (sorry, The Lord Bragg CH – but he is so familiar from his broadcasts over the years that he seems like an old friend) interjected when Dr James Hammond (Reader in Geophysics at Birkbeck, University of London) was talking about forces involved in plate tectonics to ask "Where does this energy come from?". To this, Dr Hammond replied,

"The whole thing that drives the whole caboose?
It comes from plate tectonics. So, essentially the earth has one objective, it has had one objective for four and half billion years, and that's to cool down. We're [on] a big lump of rock floating in space, and it's got all this primordial energy, so we are going right back here, there's all this primordial energy from the the material coming together, and it's trying to cool down."
Dr James Hammond talking on 'In Our Time' ¹

My immediate response, was that this was teleology – seeing purpose in nature. But actually, this might be better described as anthropomorphism. This explanation presents the earth as being the kind of agent that has an objective, and which can act in the world to work towards goals. That is, like a human:

The earth has an objective.
The earth tries to achieve its objective.

Read about teleology

Read about anthropomorphism

A flawed scientific account?

Of course, in scientific terms, the earth has no such objective, and it is not trying to do anything as it is inanimate. Basic thermodynamics suggests that an object (e.g., the earth) that is hotter than its surroundings will cool down as it will radiate heat faster than it absorbs it. ² (Of course, the sun is hotter than the earth – but that's a rather minority component of the earth's surroundings, even if in some ways a very significant one.) Hot objects tend to cool down, unless they have an active mechanism to maintain their temperature above their ambient backgrounds (such as 'warm-blooded' creatures). ³

So, in scientific terms, this explanation might be seen as flawed – indeed as reflecting an alternative conception of similar kind as when students explain evolutionary adaptations in terms of organisms trying to meet some need (e.g., The brain thinks: grow more fur), or explain chemical processes in terms of atoms seeking to meet a need by filling their electron shells (e.g., Chlorine atoms share electrons to fill in their shells).

Does Dr Hammond really believe this account?

Does Dr Hammond really think the earth has an objective that it actively seeks to meet? I very much doubt it. This was clearly rhetorical language adopting tropes seen as appropriate to meet the needs of the context (a general audience, a radio programme with no visuals to support explanations). In particular, he was in full flow when he was suddenly interrupted by Melvin, a bit like the annoying child who interrupts the teacher's carefully prepared presentation by asking 'but why's that?' about something it had been assumed all present would take for granted.

Imagine the biology teacher trying to discuss cellular metabolism when young Melvin asks 'but where did the sugar come from?'; or the chemistry teacher discussing the mechanism of a substitution reaction when young Melvin asks why we are assuming tetrahedral geometry around the carbon centre of interest; or young Melvyn interrupting a physics teacher's careful exposition of why pV = ¹/₃nmc² by asking how the gas molecules came to be moving in the first place.

Of course, part of Melvin's job in chairing the programme IS to act as the child who does not understand something being taken for granted and not explained, so vicariously supporting the listener without specialist background in that week's topic.

Effective communication versus accurate communication?

Science teachers and communicators have to sometimes use ploys to 'make the unfamiliar familiar'. One common ploy is to employ an anthropomorphic narrative as people readily relate to the human experience of having goals and acting to meet needs and desires. Locating difficult ideas within such a 'story' framework is known to often make such ideas more accessible. Does this gain balance the potential to mislead people into thinking they have been given a scientific account? In general, such ploys are perhaps best used only as introductions to a difficult topic, introductions which are then quickly followed up by more technical accounts that better match the scientific narrative (Taber & Watts, 2000).

Clearly, that is more feasible when the teacher or communicator has the opportunity for a more extensive engagement with an audience, so that understanding can be built up and developed over time. I imagine Dr Hammond was briefed that he had just a few minutes to get across his specific points in this phase of the programme, only to then find he was interrupted and asked to address additional background material.

As a scientist, the notion of the earth spending billions of years trying to cool down grates as it reflects pre-scientific thinking about nature and acts as a pseudo-explanation (something which has the form of an explanation, but little substance).

Read about pseudo-explanations

As cooling is a very familiar everyday phenomena, I wondered if a basic response that would avoid anthropomorphism might have served, e.g.,

When the earth formed, it was very much hotter than today, and, as it was hotter than its surroundings, it has been slowly cooling ever since by radiating energy into space. Material inside the earth may be hot enough to be liquid, or – where solid – be plastic enough to be deformed. The surface is now much cooler than it was, but inside the earth it is still very hot, and radioactive processes continue to heat materials inside the earth. We can understand seismic events as driven by the ways heat is being transferred from deep inside the earth.

However, just because I am a scientist, I am also less well-placed to know how effective this might have been for listeners without a strong science background – who may well have warmed [sic] to the earth striving to cool.

Dr Hammond had to react instantly (like a school teacher often has to) and make a quick call based on his best understanding of the likely audience. That is one of the difference between teaching (or being interviewed by Melvin) and simply giving a prepared lecture.

Work cited:

Taber, K. S. and Watts, M. (1996) The secret life of the chemical bond: students' anthropomorphic and animistic references to bonding, International Journal of Science Education, 18 (5), pp.557-568.

Note

¹ Speech often naturally has repetitions, and markers of emphasis, and hesitations that seem perfectly natural when heard, but which do not match written language conventions. I have slightly tidied what I transcribed from:

"The whole thing that drives the whole caboose? It comes from plate tectonics, right. So, essentially the earth, right, has one objective, it has had one objective for four and half billion years, and that's to cool down. Right, we're a big lump of rock floating in space, and it's got all this primordial energy, so we are going right back here, there's all this primordial energy from, from the the material coming together,⁴ and it's trying to cool down."

² In simple terms, the hotter an object is, the greater the rate at which it radiates.

The hotter the environment is, the more intense the radiation incident on the object and the more energy it will absorb.

Ultimately, in an undisturbed, closed system everything will reach thermal equilibrium (the same temperature). Our object still radiates energy, but at the same rate as it absorbs it from the environment so there is no net heat flow.

³ Historically, the earth's cooling was an issue of some scientific controversy, after Lord Kelvin (William Thomson) calculated that if the earth was cooling at the rate his models suggested for a body of its mass, then this was cooling much too rapid for the kind of timescales that were thought to be needed for life to have evolved on earth.

⁴ This is referring to the idea that the earth was formed by the coming together of material (e.g., space debris from a supernova) by its mutual gravitational attraction. Before this happens the material can be considered to be in a state of high gravitational potential energy. As the material is accelerated together it acquires kinetic energy (as the potential energy reduces), and then when the material collides inelastically it forms a large mass of material with high internal energy (relating to the kinetic and potential energy of the molecules and ions at the submicroscopic level) reflected in a high temperature.

NASA puts its hand in the oven

A tenuous analogy

Keith S. Taber

The Parker Solar Probe

I recently listened to NASA's Nicky Fox being interviewed about the Parker Solar Probe which (as the name suggests) is being used to investigate the Sun.

Screenshot from http://parkersolarprobe.jhuapl.edu (© 2019 The Johns Hopkins University Applied Physics Laboratory LLC. All rights reserved. Permission for use requested.)

There is a website for the project which, when I accessed it (28th December 2021), suggested the spacecraft was 109 279 068 km from the Sun's surface (which I must admit would have got a marginal comment on one of my own student's work along the lines "is the Sun's surface so distinctly positioned that this level of precision can be justified?") and travelling at 57 292 kph (kilometers per hour). This unrealistic precision derives from the details being based on "mission performance modeling [sic] and simulation and not real-time data…" Real-time data is not necessarily available to the project team itself – the kind of shielding needed to protect the spacecraft from such extreme conditions also creates a challenge in transmitting data back to earth.

But the serious point is that returning to the website at another time it is possible to see how the probe's speed and position have changed (as shown on 'the Mission' webpage – indeed by the time I took the 'screenshot' it had moved about 7000 km), as the spacecraft moves through a sequence of loops in space orbiting the Sun on a shifting elliptical path that takes it periodically very close (very close, in solar system terms, that is) to the sun. Like any orbiting body, the probe will be moving faster when closest to the sun and slowest when furthest from the sun. (The balance shifts between its kinetic and potential energy – as it works to move away against the sun's gravity when receding from it ¹.)

Touching the Sun

Publicity still from the Danny Boyle film 'Sunshine'

Getting too close the Sun – with its high temperature, the 'solar wind' of charged particles emitted into space, occasional solar flares, and the high flux of radiation from across the electromagnetic spectrum – is very dangerous, making the design and engineering of any craft intended to investigate our local star up close very challenging. A key feature is a protective heat shield facing the Sun . This was the premise of the sci-fi film 'Sunshine' ².

For the Parker probe

"the spacecraft and instruments will be protected from the Sun's heat by a …11.43 cm carbon-composite shield, which will need to withstand temperatures outside the spacecraft that reach nearly …1,377 degrees Celsius"
"At closest approach to the Sun, while the front of Parker Solar Probe' solar shield faces temperatures approaching … 1,400° Celsius, the spacecraft's payload will be near room temperature, at about [29˚C.]."
http://parkersolarprobe.jhuapl.edu

Note: Dr Fox is NOT reporting from the Parker Solar Probe – just pictured in front of an image of the sun (Dr Fox's profile on NASA website)

Dr Fox, who is Director of NASA's Heliophysics [physics of the Sun] Division, was being interviewed about data released from an earlier close approach on a BBC Science in Action podcast.

Science in Action episode broadcast 2021-12-19

"The Parker Solar probe continues its mission of flying closer and closer to the sun. Results just published show what the data the probe picked up when it dipped into the surrounding plasma. NASA's Nicky Fox is our guide."
Item on BBC Science in Action

The project is framing that event as when, "For the first time in history, a spacecraft has touched the Sun". Although the visible surface of the sun has a temperature of about 6000K (incredibly hot by human standards), the temperature of the 'atmosphere' or corona around it is believed to reach several million Kelvins. On the programme, Dr Fox was asked about how the spacecraft could survive in the sun's corona, given its extremely high temperatures.

A teaching analogy?

In response she used an analogy from everyday experience:

"We talk about the plasma being at a couple of million degrees, it's like putting your hand inside an oven, and you don't touch anything. You won't burn your hand, you'll feel some heat but you won't actually burn your hand, and so the solar wind itself, or the corona, is a very tenuous plasma, there are just not that many particles there. So, even though the whole atmosphere is at about two million degrees, the number of particles that are coming into contact with the spacecraft are [sic] very small.
The temperatures that we have to deal with are about fourteen, fifteen hundred degrees Celsius, at the maximum, which is still hot, don't…let me kid you, that's still hot, but it is not two million degrees."
Dr Fox interviewed on Science in Action

Analogies are commonly used in science, science communication and science education as one means of 'making the unfamiliar familiar' by showing how something novel or surprising is actually like something the audience is already aware of and comfortable with.

Read about science analogies

Read about making the unfamiliar familiar

If the probe had been dipped in a molten vat of some hypothetical refractory liquid at two million degrees it would have quickly been destroyed. But because the Corona is not only a plasma (an 'ionised gas')³, but a very tenuous one, this does not happen. NASA sending the probe into the corona is similar to putting one's hand in the oven when cooking. If you touch the metal around the outside you will burn yourself, but you are able to reach inside without damage as long as you do not touch the sides – as although the air in the oven can get as hot as the metal structure, it has a very low particle density compared with a solid metal. So, your hand is in a hot place, but is not in contact with much of the hot material.

Do not try this at home – at least not unless you are quick

Of course, this is not the whole story. You can reach in the oven to put something in or (with suitable protection) take something out, but you cannot safely leave your hand in there for any length of time.

When two objects at different temperature are placed in contact, heating will occur with 'heat' passing from the hotter to colder object until they are in thermal equilibrium (i.e., at the same temperature). But this is not instantaneous – it takes time.⁴ If the Parker Solar Probe had been flown into the Sun's atmosphere and left there it would have been heated till it eventually matched the ambient temperature (not 'just' 1400˚C) regardless of how effective a heat shield it had been given. Or rather, it would have been heated till its substance reached the ambient temperature, as it would have lost structural integrity long before this point.

Of course, the probe has been designed to spend some time in the coronal atmosphere collecting data, but to only dip in for short visits, as NASA is well aware that it would not be wise to leave one's hand in the oven for too long.

Note:

¹ This at least is the description based on Newtonian physics. There is an attractive, gravitational force between the Sun and the probe. As the spacecraft moves towards the sun it accelerates, and then its momentum takes it away, being decelerated by gravity.In this model gravity is a force between two bodies. (The path is actually more complex than this, as it has been designed to fly past Venus several times to adjust its trajectory round the Sun.)

In the model offered by general relativity the probe simply moves in a straight line through space which has a complex geometry due to the presence of matter/energy: a straight line which seems to us to be a shifting series of ellipses. Gravity here is best understood as a distortion from a 'flat' space. Perhaps it is clear why for most purposes scientists stick with the Newtonian description even though it is no longer the account considered to best describe nature.

² The movie poster gives a slight clue to the hazards involved in taking a manned mission to the Sun!

³ Plasma is considered a fourth state of matter: solid, liquid, gas, plasma. The expression that 'a plasma is an ionised gas' may suggest plasma is a kind of gas, but then we might also say that a gas is a boiled liquid or that a liquid is melted solid! So, perhaps what we should say is that a plasma [gas/liquid] is what you get when you ionise [boil/melt] a gas [liquid/solid].

⁴ In theory, modelling of such a process suggests it takes an infinite time for this to occur. ⁵ In practice, the temperatures become close enough that for practical purposes we consider thermal equilibration to have occurred.

⁵ This is an example of a process that can be understood as having a negative feedback cycle: temperature difference drives the heat flow, which reduces temperature difference, which therefore also reduces the driver for heat flow; so the rate of heat flow is reduced, so therefore the rate of temperature change is reduced… This is a similar pattern to radioactive decay – both follow an 'exponential decay' law.

Temperature is measuring the heat of something …

Keith S. Taber

Image by Peter Janssen from Pixabay

Bill was a participant in the Understanding Science Project. Bill, then in Y7, was telling me about work he had done in his science class on the states of matter, and what happened to the particles that made up objects during a change of state. He suggested that "when a solid goes to a liquid, the heat gives the particles energy to spread about, and then when its a liquid, it's got even more energy to spread out into a gas". Later in the interview I followed up to find out what Bill understood by heat:

Now you mentioned earlier, something about heat. When you were talking about the experiment you did.
Yeah.
Yeah. So tell me about the heat again, what's, how does the heat get involved in this solids, liquids and gases?
When I heat, when heat comes to a solid, it will have, erm, a point where it will go down to a liquid,
Okay,
A melting points of the, the object.
Do you know what heat is? If you had a younger brother or sister, and they said to you, 'you are good at science, what's heat?'
I'm not sure how I can explain it, 'cause it's, it can be measured at different temperature, it can be measured at temperature, erm, by degrees Celsius, degrees Fahrenheit, and – I'm not really sure how I could explain what it is, but, I know it can be measured and changed.
So is it the same thing as temperature, do you think, or is it something different?
Erm, I think temperature is measuring the heat of something.
So they're related, they're to do with each other?
Yeah.
But they are not exactly the same?
No.

Bill appreciated that heat and temperature were not the same, but was not entirely clear on the relationship. Distinguishing between heat and temperature is a recognised challenge in teaching and learning physics.

We commonly introduce temperature as a measure of how hot or cold something is – which relates to phenomena that all students have experienced (even if our actual perception of temperature is pretty crude). Heating is a process, and heat is sometimes considered to be energy being transferred due to a difference of temperature (although energy is a very abstract notion and there is much discussion in science teaching circles about the best language to be used in teaching about energy).

Put simply, it is reasonable to suggest a very hot object would have a high temperature, but not that it contained a lot of heat. So, it is strictly wrong to say that "temperature is measuring the heat of something" (and it would be more correct, if not very technical, to say instead "temperature is measuring the hotness of something – how hot something is"). Perhaps the idea Bill wanted to express was more about the heat that one can feel radiating form a hot object (but likely that is an interpretation suggested by the canonical science use of 'heat'?)

This is one of those situations where a student has an intuition or idea which is basically along the right lines, in the sense of knowing there is an association or link, but strictly not quite right – so, an alternative conception. In a teaching situation it might be useful to know if a student actually has a firm conception that temperature measures the amount of heat, or (as seems to be the case with Bill) this is more a matter of using everyday language – which tends to be less precise and rigid than technical language – to express a vague sense. If a student has a firm notion that hot objects contain heat, and this is not identified and responded to, then this could act as a grounded learning impediment as it will likely distort how teaching is understood.

The teacher is charged with shifting learners away from their current ways of thinking and talking, towards using the abstractions and technical language of the subject, such as the canonical relationship between heat and temperature – and this often means beginning by engaging with the learners' ideas and language. Arguably the use of the term 'heat capacity' (and 'specific heat capacity') which might suggest something about the amount of heat something can hold, is unhelpful here.

Particles in ice and water have different characteristics

Making a link between particle identity and change of state

Keith S. Taber

Bill was a participant in the Understanding Science Project. Interviews allow learners to talk about their understanding of science topics, and so to some extent allow the researcher to gauge how well integrated or fragmented a learner's ideas are.

Occasionally there is a sense of 'seeing the cogs turn', where it appears that the interview is not just an opportunity for reporting knowledge, but a genuine site for knowledge construction (on behalf of the students, as well as the researcher) as the learner's ideas seem to change and develop in the interview itself.

One example of this occurred when Bill, a Y7 student, explained what he had learnt about particles in solids, liquids and gases. Bill seemed unsure if the particles in different states of matter were different, or just had different properties. However, when asked about a change of state Bill related heating to changes in the way particles were arranged, and seemed to realise this implied the particles themselves were the same when a substance changes state. Bill seemed to be making a link between particle identity and change of state through the process of answering the researcher's questions.

Bill introduced the idea of particles when talking about what he had learn about the states of matter

Well there's three groups, solids, liquids and gases.
So how do you know if something is a solid, a liquid or a gas?
Well, solids they stay same shape and their particles only move a tiny bit.

This point was followed up later in the interview.

So, you said that solids contain particles,
Yeah.
They don't move very much?
No.
And you've told me that ice is a solid?
Yeah.
So if I put those two things together, that tells me that ice should contain particles?
Yeah.
Yeah, and you said that liquids contain particles? Did you say they move, what did you say about the particles in liquids?
Er, they're quite, they're further apart, than the ones in erm solids, so they erm, they try and take the shape, they move away, but the volume of the water doesn't change. It just moves.
Okay. So the particles in the liquid, they seem to be doing something a bit different to particles in a solid?
Yeah.
What about the particles in the gas?
The gas, they, they're really, they're far apart and they try and expand.
Does that include steam, because you said steam was a gas?
Yeah.
Yeah?
I think.
So, we've got particles in ice?
Yeah.
And they have certain characteristics?
Yeah.
And there are particles in water?
Yeah.
That have different characteristics?
Yeah.
And particles in gas, which have different characteristics again?
Yeah.
Okay. So, are they different particles, then?
N-, I'm not sure.

There are several interesting points here. Bill reports that the particles in liquids are "further apart, than the ones in … solids". This is generally true when comparing the same substance, but not always – so ice floats in water for example. Bill uses anthropomorphic language, reporting that particles try to do things.

Of particular interest here, is that at this point in the interview Bill did not seem to have a clear idea about whether particles kept their identify across changes of state. However, the next interview question seemed to trigger a response which clarified this issue for him:

So have the solid particles, sort of gone away, when we make the liquid, and we've got liquid particles instead?
No {said firmly}, when a solid goes to a liquid, the heat gives the particles energy to spread about, and then when its a liquid, it's got even more energy to spread out into a gas.
So we're talking about the same particles, but behaving differently, in a solid to a liquid to a gas?
Yeah.
That's very clear.

It appears Bill had learnt a model of what happened to the particles when a solid melted, but had not previously appreciated the consequences of this idea for the identity of particles across the different states of matter. Being cued to bring to mind his model of the effect of heating on the particles during melting seemed to make it obvious to him that there were not different particles in the different states (for the same substance), where he had seemed quite uncertain about this a few moments earlier.

Whilst this has to remain something of a speculation, the series of questions used in research interviews can be quite similar in nature to the sequences of questions used in the method of instruction known as Socratic dialogue – a method that Plato reported being used by Socrates to lead someone towards an insight.

So, a 'eureka' moment, perhaps?