Talk:Thermal equilibrium

A chart has newly been put into this article. I am not impressed that the chart is supported by its cited references or that its cited references are reliable sources. I do not pretend to have studied this matter, and perhaps my not being impressed is not a reliable guide.

That the chart may be shown in other places in Wikipedia is not a justification for showing it here. Wikipedia is not a reliable source. And if it is in other places, presumably it might be appropriate for them, and this suggests that they may be its natural homes, not here.

I am not impressed that greenhouse gas estimates are relevant to the present article on Thermal equilibrium. They are not otherwise mentioned in the article, and are hardly directly related in simple terms to the general concept of thermal equilibrium.

I have not reverted the edit because I do not wish to enter an edit contest on a matter that I have not closely studied.

I would like to know other opinions about the reliability of sourcing and relevance of this table to this article.Chjoaygame (talk) 02:06, 10 January 2012 (UTC)

I have now learnt that the table in question is mainly related to the article Gliese 581 g, and I think that if the entry Equilibrium temperature is not deleted (as I would like to see it deleted), then one might consider targeting the redirect to Gliese 581 g. I also note that the references there are fuller than they are here, and might for all I know be better. I still don't like the presence of the table here in the present article on 'Thermal equilibrium' and I think it seems like some sort of promotion that it is put here.Chjoaygame (talk) 03:01, 10 January 2012 (UTC)

I most certainly agree that the table does not belong in the article, which is far broader and with a far more theoretically precise meaning than would provide for the arbitrary astronomical associations that this table would be making. The vast majority of the readers of this article will find it peripheral to the concept and it will only be so much clutter. — Quondum^☏✎ 07:20, 10 January 2012 (UTC)

► List of 41 planet articles refering to Equilibrium Temperature.
You created this other article to create a redirect for Equilibrium Temperature and to get rid of the chart, It belongs in this article or the other one, make up your mind. 24.79.40.48 (talk) 23:02, 10 January 2012 (UTC)

As I read the above comment by editor 24.79.40.48, he means that the article Thermal equilibrium was created in order to create a redirect for Equilibrium temperature and to get rid of the chart. I will comment assuming this is the right reading:

The article 'Thermal equilibrium' was created on 12 Feb 2004. The comment on its creation reads "#REDIRECT Thermodynamic equilibrium". I do not see a reference to 'Equilibrium temperature' there. The article contained no content till 21 May 2011, when it was given a content not too far from its present content. On that occasion, there was no mention of equilibrium temperature or of the chart that is currently being discussed. On that occasion, the editor who gave that content (me) had no idea of the existence of the chart that is currently being discussed, and no thought of a special term 'equilibrium temperature'.

The entry 'Equilibrium temperature' was created on 17 Jun 2007 as a redirect to Thermodynamic equilibrium#Thermal equilibrium. On that occasion, there was no mention of equilibrium temperature or of the chart that is currently being discussed.Chjoaygame (talk) 04:36, 11 January 2012 (UTC)

Don't get too serious – consider some comic relief. — Quondum^☏✎ 05:18, 11 January 2012 (UTC)

The proposed table is illustrated just above. It is about planets, and the question arises as to its fit to the present article.Chjoaygame (talk) 04:41, 15 April 2012 (UTC)

The word 'flow' appears about 12 times in connection with heat in this article. Flowing is a fundamental property of fluids, only fluids can flow. There is an old concept, long since superseded, of heat as 'a fluid that flows' called 'caloric'. Are we to understand that this article is about caloric? --Damorbel (talk) 07:50, 11 January 2012 (UTC)

There is hardly a word in the English or any other natural language that is not used metaphorically at some level. This is a primary mechanism in the evolution of human languages. The word "flow" and "fluid" are used very widely to describe things that are not classically "fluids". Traffic flows. Someone can move fluidly. Energy flows, and has a density. Electricity flows. Heat flows. — Quondum^☏✎ 10:24, 11 January 2012 (UTC)

"The word "flow" and "fluid" are used very widely to describe things that are not classically "fluids"." In scientific terms? This kind of thing is just misleading. Using a metaphor in place of a simili is sloppy thinking and about as unscientific as you can get. The whole reason the caloric theory collapsed was because 'heat' doesn't flow. The caloric concept should be finished now because it did not match the (scientific) observations, just like the aether. --Damorbel (talk) 11 January 2012 (UTC)

Surely you're not being serious? I'd be hard put to find another scientific term with the same meaning. Perhaps you have a suggestion? I get 2.6 millions of hits on Google books for "heat flow", apparently primarily technical publications. Maths is far more so – you pretty much have to relearn your entire vocabulary, since common terms get reused endlessly in ways that are unfathomable. The same word often has different meanings in even closely related branches of math. Vector, bundle, field, connection, ring, group, derivative - the list is endless, and their meaning is not remotely what you'd expect of them. — Quondum^☏✎ 11:16, 11 January 2012 (UTC)

"Surely you're not being serious?" Of course I am. I might add, are you familiar with thermal physics? If you are then you should be aware that using fluid flow equations, in the absence of a real fluid, will give a false answer. Further, do you see your "2.6 millions of hits on Google books for "heat flow"" as a "reliable source" for your argument? --Damorbel (talk) 11:59, 11 January 2012 (UTC)

I'm not aware of anyone but you suggesting that fluid flow equations would be used to describe heat purely on the strength of use of the word "flow". I note you've failed to attempt to suggest an alternative term that may make you feel happier. — Quondum^☏✎ 13:23, 11 January 2012 (UTC)

"I'm not aware...." Heat is the kinetic energy of particles, it is usually measured by the temperature of the particles. The energy of the particles can be changed in many different ways, work can be done on particles enclosed in a cylinder (more generally you can say 'the volume is changed by a force'); there is no 'flow' involved in the associated temperature rise ('increase in heat'). Simmilarly the particles may change their chemical state and the temperature changes, mostly one thinks of combustion and the associated temperature rise but the reaction may be endothermic and the temperature falls. These are two very common cases where there is no 'flow' taking place but heating (or cooling) are apparent through the temperature change.

I agree that, as your Google search revealed, 'heat flow' is a commonly used expression but it is not precise enough for a serious reference work. --Damorbel (talk) 14:18, 11 January 2012 (UTC)

This is a conversation fit for a Lewis Carroll story. Check it out with Humpty Dumpty. A curious delusion afflicts some persons with cravings or assumptions of authority: they decide, rightly or wrongly, that some particular expression is appropriate to a particular meaning or usage, then proclaim uncompromisingly that any other usage is wrong. I am not aware of any language in which any such assumption is justified, but I can confidently state that it does not wear well in general in English, not even in technical connections. So let us not make worse fools of ourselves than necessary. Flow is restricted to fluids, you say? Really? What about the ebb and flow of conversation? The feast of reason and flow of soul? We seem to be experiencing troublesome viscosity impeding those in the present conversion just now. What happens if a woman in flowing garments encounters a towel? (In public especially?) What fluid flow equations in particular would you expect to describe a fluid situation or flowing robe or gesture? What alternative term would you prefer, rather than heat flow? Transfer? Convey? Donate? Travel? Induce? Teleport? Conduct? Sorry, can't use any of those for heat; they have been snapped up for other semantic content already. Poor old heat will stay put until we find a word that refers to changes in its situation and never refer to anything but that. Exactly what gives you the idea that if we use terms such as heat flow or heat flux, readers are doomed to doctrinal and literal acceptance of the caloric theory, I cannot guess, but trust me, the effect is not universal. I know a few readers wax choleric at the very suggestion of caloric. Just a suggestion: try to find something substantial to expend your energy on; this one not only is a loser, but exhibits your intellect in a very poor light. JonRichfield (talk) 11:23, 17 April 2012 (UTC)

"This is a conversation fit for a Lewis Carroll story." Um - not really. The English language is, to a great extent dependent on context for its very great flexibility; another source of flexibility in English is the, often subtle, shade of meaning derived from changes in word order; this is not really a big feature in e.g. German, which makes English quite difficult for Germans.

The article is about physics, the concept you propose that words can somehow have been 'snapped up for other semantic content' is quite foreign to English; it exists in other language. e.g. Japanese where each pictogram may well have an exact meaning.

However, in English, when seeking a precise meaning for 'heat' there have been a number of theories that failed because they did not explain the observed facts, among these is the caloric theory which describes heat as some sort of fluid. The caloric theory failed because, with heat, no properties in common with the generalities of fluids, e.g. gases and liquids, were ever observed.

I am reasonably familiar with the use of the word 'flow' in all the contexts you mention and possibly a few you don't but there are only a few that can safely be used with any accuracy in the context of 'heat'. You suggest "Transfer? Convey? Donate? Travel? Induce? Teleport? Conduct;" of which the first and the last (transfer and coduct) are in everyday use in scientific discussions on heat; you could have added 'diffusion' and 'radiation' if you felt so inclined; in fact, as far as the English language is concerned you can add any word you like provided you define its contextual meaning. Another example of the odd use of words in a scientific context can be found in particle physics where 'strangeness' is an important property, a property not generally to be confused with 'unfamiliarity'; similarly in addition to strangeness, the other five flavours of quarks 'up', 'down', 'charm', 'bottom', and 'top'. These useful concepts only have meaning in particle physics in the same way that 'flow' only has a physics meaning in connection with fluids. --Damorbel (talk) 10:08, 18 April 2012 (UTC)

My condign apologies for not mentioning all the uses of "flow" that occurred to you, but I had hoped that the examples I gave would illustrate the point adequately. You will let me know if you need any help with a longer list, won't you? Your authority for the claim that only a few can with any safety be used with any accuracy in the context of 'heat' would have been far more reassuring if it had been less authoritative. Could you please satisfy my curiosity with examples of that majority where it would be dangerous to use them with any accuracy, whether in connection with heat or anything else? "Heat flow" is a common metaphor, both in general, and in physics. Possibly in the good ol' days when caloric reigned and rained down on scientific dinosaurs, it was seen as more than a metaphor, but those days and their dinosaurs, like most other dinosaurs, have gone, so I assure you that we might rely on the metaphoric status of "heat flow". Like any metaphoric usage, it bears some semantic relationship to its literal usage, but not an exact correspondence. If it did, it would not be a metaphor, would it? Do you grasp that? I hoped you would. Did you have any difficulty grasping it? I thought you might not. Are you aware that for your reception and comprehension of the term "grasp", you were employing your understanding of a metaphorical relationship? One more tenuous than the "flow" of heat"? Kapierst? And yet you appear to have come safely through? I am so glad!. Then what gives you the impression that as soon metaphor flows in at the door, caloric flows in at the window? Speaking strictly personally, I cannot offhand remember encountering any student in a physics class who, on encountering the expression "heat flow", was ensnared by the charms of caloric. As for members of the physics-innocent public on the Clapham omnibus, however great the peril, they probably would understand so little of the matter that they would be no worse off if, on hearing the expression, they leaped up and cried: "Heat flow! Of course! Caloric! Let's apply a few fluid flow equations!" But I might be wrong there. Feel welcome to enlighten me.

On a slightly different tack, let us consider some of the technical physics terms you mentioned. Let me assist you in your difficulty. Consider strangeness as a quantum value. Does it have a specific and limited meaning in particle physics? Certainly it does. Well done! So if physicist A says to physicist B in the laboratory: "Good grief! That's strange! Leave at once; that gas cylinder is swelling!" B will reply with a patronising smile: "My dear colleague, surely you mean 'peculiar', or perhaps 'alarming'? Strangeness cannot possibly have anything to do with it!" Nevertheless, strange things happen in Anglophone physics labs, I can assure you. Like one youngster staring out of the window and saying: "Wow! Look at that charming bottom!" And his colleague with his back to the window replying: "Thanks. It took me over an hour to attach it to the electromagnet's coolant tank. Prof will be pleased I reckon". Somewhere in the same lab there is likely to be a wall chart of various quark types. As in "Du wisst ein Quark davon!" Maybe our only recourse is to forbid the use of English in physics labs and stick safely to German and Japanese. Cheers, JonRichfield (talk) 16:17, 18 April 2012 (UTC)

Oh dear! The hazards of irony.... The problem with 'heat -> flowing' is really quite dramatic because in the 19th century the concept was frequently disputed; it was almost as heavily disputed as Newton's corpuscular theory of light versus the wave theory. The difficulty with 'heat flowing' is that it doesn't explain anything; it is a nice concept that will lead you comfortably by the hand but, like a false friend, dump you at the first difficulty. The friendly bit can be warm water (or air) transporting ease and warmth around your house; but these fluids eventually cool down and your heat has disappeared without explanation! Such metaphors are a massive scientific hazard, spreading confusion everywhere.

In a scientific context the right words matter, that is why scientists define new meanings for words; the new meanings often sound like 'hocus pocus' - only available to the cognoscenti - but this is necessary in a languages like English with a lesser ability to create new words.

Your defense that students were not "ensnared by the charms of caloric" is utterly invalid, did they all get 100% in thermodynamics? There is an enormous amount of confusion about thermal physics, currently a great many people are being ensnared into paying higher taxes because politicians are relying on their ignorance of the second law of thermodynamics. Really, your position is quite untenable! --Damorbel (talk) 19:52, 19 April 2012 (UTC)

I have moved the table to the article on the Black body because there a lot of editors are firing away and may give the proper placement of the table a more consensual assessment than here, which is a backwater that no one seems to visit. I will shortly also change the redirect from Equilibrium temperature.Chjoaygame (talk) 00:05, 28 January 2012 (UTC)

The opening section is quite incorrect; thermal equilibrium is not a theoretical physical concept, it is a thermodynamic state comprising a uniform temperature i.e. a physical system is in equilibrium when it can be described as having a single temperature throughout.

This excludes much of the further content of the article that assigns multiple temperatures to a system, so that heat transfer and/or material flow takes place. Such systems are not in thermal equilibrium because their entropy is less than maximum. Much of the article is therefore not about thermal equilibrium and should be removed. --Damorbel (talk) 11:45, 5 October 2012 (UTC)

Dear Damorbel, I strongly suggest you read some books about thermodynamics before dogmatising about it like this.

You have a major problem that you also need to work on. You have a habit of trying to work with more or less compositional semantics, and of mixing ordinary language with terms of art. This leads you to invent ideas in your mind that are not intended or not justfied by what you read, and then to try to force your inventions on others.Chjoaygame (talk) 14:06, 5 October 2012 (UTC)

The article doesn't mention entropy, should it? --Damorbel (talk) 18:02, 5 October 2012 (UTC)

The essential feature of thermal equilibrium is maximum entropy, which translates into uniformity of temperature. This uniformity arises from the second law of thermodynamics. The point being that energy transfer declines to zero as the temperature gradients approach zero. Statements such as the concept also requires that any flow of heat by thermal conduction or by thermal radiation into or out of one part of the body be balanced by a flow of heat in the opposite sense into or out of another part of the body in the article are completely invalid; in terms of thermodynamics to be in equilibrium a system must have maximum entropy, this is obviously impossible for a system having unequal temperatures. --Damorbel (talk) 16:31, 7 October 2012 (UTC)

Though a system in thermodynamic equilibrium through a thermally conductive wall with another system is necessarily in thermal equilibrium with it, thermal equilibrium is not necessarily thermodynamic equilibrium. Thermal equilibrium refers to zero flow of heat between the system of interest and the thermometric system with which the system of interest is in thermal contact. For example, one says such things as "Which of the two do you have with a fever of 98.4°F?" about bodies that are not in thermodynamic equilibrium.

"An explicit distinction between 'thermal equilibrium' and 'thermodynamic equilibrium' is made by C.J. Adkins. He allows that two systems might be allowed to exchange heat but be constrained from exchanging work; they will naturally exchange heat till they have equal temperatures, and reach thermal equilibrium, but in general will not be in thermodynamic equilibrium. They can reach thermodynamic equilibrium when they are allowed also to exchange work.^[1]

"Another explicit distinction between 'thermal equilibrium' and 'thermodynamic equilibrium' is made by B. C. Eu. He considers two systems in thermal contact, one a thermometer, the other a system in which several irreversible processes are occurring. He considers the case in which, over the time scale of interest, it happens that both the thermometer reading and the irreversible processes are steady. Then there is thermal equilibrium without thermodynamic equilibrium. Eu proposes consequently that the zeroth law of thermodynamics can be considered to apply even when thermodynamic equilibrium is not present; also he proposes that if changes are occurring so fast that a steady temperature cannot be defined, then "it is no longer possible to describe the process by means of a thermodynamic formalism. In other words, thermodynamics has no meaning for such a process."^[2]"

Chjoaygame (talk) 04:55, 8 October 2012 (UTC)

The matter in hand is entropy in equilibrium and non-equilibrium sysem states, it is not mentioned in the article and you do not mention it here in the 'talk' page; this is a serious deficiency since maximum entropy is an absolute requirement for thermal equilibrium. Since you don't mention it you may not agree but ignoring the matter is not really an option. --Damorbel (talk) 05:36, 8 October 2012 (UTC)

The currently predominant view held by reliable sources is that thermal equilibrium is primarily a matter for the zeroth law of thermodynamics, and does not require for its definition any mention of entropy or the first, second, or third laws of thermodynamics. Indeed such sources seem to take pride in the primacy of the zeroth law and the concept of thermal equilibrium. They teach that the notion of thermal equilibrium is theoretically prior to the notion of entropy and should be expounded in its own right before theoretical development of the idea of entropy. You are proposing that "The matter in hand is entropy", but that is your lead. It seems from what you write that you do not distinguish between the terms thermal and thermodynamic equilibrium. Such a distinction is appropriate ground-work for a subsequent consideration of entropy. I am not saying that entropy has no place in this article, but I am saying that currently the article, as far as it goes, is valid without it; and that its place, if it were put into this article, would not be primary. You are trying to turn around the weight of doctrine of current reliable sources, apparently without being aware that you are doing so, and apparently without having read them for yourself. Some more careful thought and study and reading should lead you to understand that your assertion that "maximum entropy is an absolute requirement for thermal equilibrium" is not a well constructed and valid statement. I repeat my strong suggestion that you should read a textbook or two about thermodynamics, instead of inventing your own scheme of ideas and trying to impose it on others.Chjoaygame (talk) 06:25, 8 October 2012 (UTC)

So when, in Thermal Physics - Kittel & Kroemer p39ff, it is written: The last equality (22) leads us ... to the concept of temperature. We know the ... rule: in thermal equilibrium the temperatures ... are equal: T₁ = T₂

they are incorrect?

And when, on p43 referring to Fig 2.7, Kittel & Kroemer write:

If the temperature τ₁ is higher than τ₂, the transfer of a positive amount of energy δU from system 1 to system 2 will increase the total entropy σ₁ + σ₂ of the combined systems over the initial value ... In other words, the final system will be in a more probable condition [state] if energy flows from the warmer body to the cooler body when the thermal contact is established. This is an example of the law of increasing entropy

they are incorrect? --Damorbel (talk) 07:35, 8 October 2012 (UTC)

Dear Damorbel, you have a serious problem of understanding: you are more or less insensitive to overall or large-scale inferential structure in physics. Overall inferential structure is important in the presentation of physics. In times past, inferential structure was taught as part of the syllabus in dialectic and logic, but it seems that you did not attend to it, and have not developed a sensitivity to it through experience in study of physics. Important distinctions that are made in logic and dialectic are between definitions, theoretical principles, axioms or postulates, empirical observations and demonstrations, empirical generalizations, inferences, deductions, inductions, abductions, hypotheses, assertions, assumptions, conclusions, contradictions, inconsistencies, incoherences, and theorems. These all have their places in the presentation of physics, but you seem more or less unable to see how they fit together to provide overall inferential structure, apparently because you have not attended to it or do not value it. Your rhetorical questions just above seem to support this reading of the appearances. As I have mentioned before, you may not be entirely to blame for your difficulty here: some writers, including Kittel & Kroemer, and Reif, regrettably think they are very clever in trying to teach thermodynamics as a consequence of or as part of statistical mechanics. Thus Kittle & Kroemer actually entitle their text Thermal Physics; the result is that students become muddled about the overall inferential structure of the subjects, and get into the difficulties such as those that beset you. Until you understand and try to remedy this problem, you will continue to be more or less beyond help.Chjoaygame (talk) 08:37, 8 October 2012 (UTC)

My question was about entropy in connection with thermal equilbrium. It would seem that you find an objection in logical form to mentioning entropy in the article (overall or large-scale inferential structure in physics). Logical form can not be a real reason for excluding discussion of entropy from the article on thermal equilibrium. Entropy, as identified by Kittel & Kroemer (and very many others) lies at the heart of thermal equilibrium (and Thermodynamic Equlibrium!). Would you care to expand on your objection? --Damorbel (talk) 09:06, 8 October 2012 (UTC)

I wrote above: "I am not saying that entropy has no place in this article, but I am saying that currently the article, as far as it goes, is valid without it; and that its place, if it were put into this article, would not be primary." It seems you have ignored or mistakenly read that. Indeed, many of the things I write to you, you seem to ignore. I have mentioned in the past that usually it is practically futile to try to have a conversation with you. The underlying reason for that is that you are driven by an irresistible urge to force onto others your invented ideas which you think tell about the physics, and this driven urge makes you unable to converse rationally about the physics. You just divert attempts to converse with you into endless goings around in futile circles, centred on your apparently at present irresistible urge to force your own invented views onto others. It is a waste of time for me to respond to your requests such as the one above "Would you care to expand on your objection?" The textbooks explain this matter each in its own way, though more or less consistently, but you reject their explanations in favour of your own inventions. I cannot expect to succeed where the textbooks fail to help you. Until you understand and try to remedy this problem, you will continue to be more or less beyond help.Chjoaygame (talk) 13:04, 8 October 2012 (UTC)

Chjoaygame you write "The textbooks explain this matter each in its own way". Do you have a link to a textbook that explains thermal equilibrium (like the current aricle) without mentioning entropy? --Damorbel (talk) 17:09, 8 October 2012 (UTC)

Chjoaygame, above you have "I am not saying that entropy has no place in this article". But it has no place!

I raised matters concerning article shortcomings, you respond to by claiming "you [Damorbel] need to read up on thermodynamics". From the fact that the article does not contain a single occurrence of the word 'entropy' and you have made no comments on the relevance entropy to thermal equilibrium, then it is a fair bet that you are quite unfamiliar with the concept of entropy.

May I therefore, to avoid prolonging this discussion unnecessarily, ask you to give a summary of why the article does not mention entropy.

You claim that my concept of thermal equilibrium is mine alone. Well the reference I gave to Kittel & Kroemer shows at least two others share my view, plus Enrico Fermi in his book Thermodynamics, (see chapter IV & V). Not only does Fermi explain entropy and thermal equilibrium clearly but he makes no distinction between thermal and thermodynamic equilibrium, such a distinction being yours only.--Damorbel (talk) 14:02, 8 October 2012 (UTC)

In the section of heat by conduction and radiation between systems I have removed the last line: "For thermodynamics, it is considered that convection transports internal energy by bulk flow; this is considered not to be transfer of heat as such" for various reasons:-

1/ Bad style, the title refers to conduction and radiation only, not convection.

2/ In the line it says 'it is considered' with no indication (link; ref.?) just who considers? POV thus.

3/ The introduction says "Heat can flow into or out of a closed system" whereas the editor writes (!) "it is considered that convection transports internal energy". In or out? Decide please!

This 'stuff' is very bad, this editor is unable to epxress his ideas. --Damorbel (talk) 18:12, 8 October 2012 (UTC)

The opening section (1st line) is:- "Thermal equilibrium is a theoretical physical concept, used especially in theoretical texts, that means that all temperatures of interest are unchanging in time and uniform in space." with three references ([1][2][3]). Refs. 1 & 2 are not available on line but ref. 3 is and the relevant cited page does not confirm the Wiki text.

What ref. 3 (Kondepudi) says (p.6) is:-

"This is the state of thermodynamic equilibrium. It is a state characterized by uniform temperature throughout the system "

Which completely contradicts the next sentence in the Wiki article:-

"When the temperatures of interest are just those in the different parts of one body."

The ref. requires only (one) uniform temperature. The Wiki article goes on to describe systems with steady state temperature differences which give rise to energy transfer (heat flow in none scientific language); this is not equilibrium because the entropy of a system with more than one temperature is always below maximum (Fermi - 'Thermodynamics' chs. IV & V). --Damorbel (talk) 06:10, 9 October 2012 (UTC)

Currently, editor Damorbel is making what seems to be a concerted attack on this article.

His many comments above and elsewhere show that he does not understand the physics in the way that is conventional today. He firmly believes that he does have an understanding, but one can easily see from what he writes that he is mistaken. Nevertheless he seems determined to force his views on this article. He makes a welter of inaccurate statements and has not bothered even to check the reliable sources that are quoted, on the spurious ground, it seems, that they are not available on the web.

I have found by repeated experience with Damorbel that he is unable to conduct a rational discussion about this kind of Wikipedia article. I do not intend at present intend to be so foolish as to try to engage in further discussion with him about his present welter of activity here, because experience has led to me expect it to be futile to try so. For the present, the best course seems to be to turn a blind eye to his activity till he settles down, and then to inspect the damage.Chjoaygame (talk) 12:00, 9 October 2012 (UTC)

In the article section: "Change of internal state of an isolated system" it has:

" but not necessarily a state of thermodynamic equilibrium, if there is some structural barrier that can prevent some possible processes in the system from reaching equilibrium "

This is not worthy to be included in the article because:-

" if... some structural barrier...[is]... prevent[ing] ... processes ": then of course the system will not reach equilibrium because it describes not one but two (or more) systems that are isolated from each other and thus, by definition, do not interact.

This section should either be modified to say something useful, or just deleted. --Damorbel (talk) 07:43, 10 October 2012 (UTC)

I have just undone this reversal. I happen to agree with the original reversal, so currently it is 2:1. The original contribution was so complicated that it was meaningless in the context of 'thermal equilibrium', since was fundamentally about temperature change. Also it speaks of 'isolated systems', yet defining its state with reference to other systems. --Damorbel (talk) 16:33, 18 October 2012 (UTC)

It seems you have lost the plot, Damorbel. I guess that it would probably not be helpful if I tried deal with this by a further edit.Chjoaygame (talk) 00:16, 19 October 2012 (UTC)

I have removed the section:-

Distinctions between thermal and thermodynamic equilibria

It represents no more than the personal view of the editor(s). It comprised personal interpretations on what Planck et al (in translation!) may have intended to say, had they agreed with the editor(s)! --Damorbel (talk) 08:42, 31 December 2012 (UTC)

...and it has been replaced without any justfication! What a shame! Utterly indefensible POV and WP:NOR. --Damorbel (talk) 12:42, 31 December 2012 (UTC)

The section is based on clear statements of three distinct and clearly cited reliable sources. It is not a personal point of view of the editor. The third citation has been added on replacement of the section, because two reliable sources were not enough for editor Damorbel. Evidently editor Damorbel has failed to register either the two previous or the third citation. Other reliable sources could be added, but three should be enough, if they are actually read.Chjoaygame (talk) 14:28, 31 December 2012 (UTC)

Clear statements? Then what is clear about:-

but not necessarily a state of thermodynamic equilibrium, if there is some structural barrier that can prevent some possible processes in the system from reaching equilibrium?

"Not necessarily". How not necessarily? "some structural barrier ... prevent some possible processes ..." "Some...."? And that is supposed to be clear? "...possible..."? This is not even original research; it is mere speculation! It has no place - anywhere!

It gets even worse:-

A system prepared as a mixture of petrol vapour and air can be ignited by a spark

Truly isolated systems hardly occur in nature, and nearly always are artificially prepared

A few tips on how to do this, please! --Damorbel (talk) 15:49, 31 December 2012 (UTC)

Reasons for this are to be found at http://en.wikipedia.org/wiki/Talk:Thermodynamic_equilibrium#This_whole_article_is_fit_only_for_deletion--Damorbel (talk) 14:19, 2 January 2013 (UTC)

I removed usually. Makes no sense to introduce this sort of question so early in the article. --Damorbel (talk) 06:38, 28 January 2013 (UTC)

It is not good to define thermal equilibrium as equality in (thermodynamic) temperature, nor to say that it follows from the zeroth law. Thermal equilibrium between two systems is a concept that must be defined prior to the statement of the zeroth law, and the zeroth law then states an additional property of thermal equilibrium - that it is an equivalence relationship, a concept which requires 3 or more systems in order to be stated. The groundwork for the definition of temperature has thus been established. Thermodynamic temperature is not defined, really, until the second law, so while the statement that the temperatures are equal is true, it is not a definition of thermal equilibrium, its circular. Thermal equilibrium is defined using the primitive concept of thermal connection. Two systems are in thermal equilibrium if they are thermally connected and their states are unchanging in time. Strictly speaking, if two systems are thermally connected and their states then begin to change, it will take an infinite time for equilibrium to attain, so it really should be expressed in more precise terms as a limit process. PAR (talk) 04:28, 30 April 2014 (UTC)

You are of course right in this. The article needs to be brought into line. I will have a go at it.Chjoaygame (talk) 12:30, 30 April 2014 (UTC) (It didn't say it followed from the zeroth law. It said it followed the zeroth law meaning it obeyed it.Chjoaygame (talk) 13:08, 30 April 2014 (UTC))

Good, thanks. I have been been low profile lately due to a new job. PAR (talk) 22:33, 30 April 2014 (UTC)

The relation of thermal equilibrium is distinct from the condition of internal thermal equilibrium. The difference is important because in the statement of the zeroth law of thermodynamics, much is made of the nature of the relation, considered as a relation. It is made into an equivalence relation by the zeroth law's assertion of transitivity. The existence of the condition of internal thermal equilibrium is one of the most fundamental postulates of thermodynamics, though it is stated explicitly as such mostly in the more careful presentations. Though it is not often examined closely, it is often presupposed for the zeroth law, that the related bodies are in their own internal states of thermodynamic equilibrium. That the relation is a relation between bodies is worth indicating explicitly right from the start.

Carathéodory postulates the existence of paths "permeable only to heat". He does not however define heat in that context. It is left unstated as the exhaustive default alternative to transfer of energy as work, between closed systems, relying on the postulate of conservation of energy. This and the older tradition differ in that the older tradition defines quantity of energy transferred as heat by calorimetry with empirical temperature, whereas the newer tradition defines it as a residual after work transfer with energy conservation. The existence of heat transfer is common to both traditions, simply postulated. The differences are two: in the method of measurement, and in the status of conservation of energy. The Carathéodory way relies on a quantity that satisfies the criteria for an empirical temperature, though labeling it 'the non-deformation variable', and assumes conservation of energy. The older tradition does not postulate, but derives, conservation of energy, from observation, by considering heat transfer as a form of transfer of energy.

Heat transfer is defined for paths permeable to heat and work, but not for paths permeable to matter. The average reader does not know intuitively that heat transfer is undefined for paths permeable to matter.

Two bodies may be connected by a path permeable to heat and work, for example a moveable conductive piston. It would be problematic to define thermal equilibrium when there is movement of the piston. Though heat and work can still be distinguished in that case, it is safer to let that be deduced from the definition of thermal equilibrium, together with other principles, than to make the distinction part of its definition.Chjoaygame (talk) 03:35, 17 June 2014 (UTC)

On the first issue, I see your point. Perhaps we should say "Two systems are in TE with each other..."? My problem with "are in a relation of" is that it is forbiddingly formal language that might discourage casual/young/non-academically inclined readers already at the first sentence of the lead of the article.

On the second issue, I have pretty much the same feeling. The more qualifiers we add in order to be precise, the less understandable the language becomes. Since we refer to heat flow, I think it's clear we are in a situation where heat flow can be defined. And I think it's also clear enough to leave implicit that a situation with a moving piston or something else doing work as the connection might be an exception. But if you feel strongly it must say "permeable only to heat" I won't object if you change it back. Waleswatcher (talk) 11:37, 18 June 2014 (UTC)

Thank you for this. Please let me think about it a little.Chjoaygame (talk) 23:20, 18 June 2014 (UTC)

The term "thermostatics" is used to refer to the field within what is typically called "thermodynamics" that studies some sort of equilibrium - this source refers to, say, thermal equilibrium.

But right now "thermostatics" redirects to Equation of state (and isn't used anywhere in that article). Shouldn't it redirect here instead? 172.56.234.186 (talk) 19:14, 15 April 2025 (UTC)