Talk:Heat/Archive 10
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Waleswatcher's destructive edit
As often with his edits, Waleswatcher's most recent edit here is destructive. I will not now try to correct it because I have experience with Waleswatcher, that he edits viciously, and does not respond to reason. His edit is faulty as follows.
Heat transfer is a well-attested concept and is the main one considered by this article. The main sources of this concept refer to heat transfer between closed systems, which occurs only by conduction and thermal radiation. The main sources are the classical approach, exemplified by Planck, and the new approach, started by Bryan 1907 and established by Caratheodory 1909 with the imprimatur of Born 1921, and currently asserted with dogmatic finality in some current textbooks. Waleswatcher is so convinced of this dogmatic finality that he even felt compelled to remove the adverb 'often' from the former sentence “"Heat" is often used interchangeably with "heat flow" and "heat transfer".”
Heat transfer between open systems is not so clearly attested in the literature of physics. The problem is to properly distinguish internal energy transfer from heat transfer due to matter transfer. This may be checked by examination of textbooks and other sources. For this reason, heat transfer by convection, which involves open systems, is not as safely defined in physics as is heat transfer by conduction and thermal radiation, which is well attested at least for closed systems. Waleswatcher's destructive edit has obliterated notice of this from the lead, and left the lead with a muddle about it.
'Heat production' is not as well attested as is heat transfer by conduction and thermal radiation, witness Waleswatcher's conviction evidenced above. 'Heat production' or 'evolution of heat' is used by some reliable thermodynamicists, especially chemists. 'Heat production' by friction, viscosity, and dissipation of chemical potential energy come in here. Though it is not quite de rigueur according to the strict doctrine of heat transfer as the only kind of heat admitted, it deserves mention with a caveat in the article. Waleswatcher's edit obliterates this point, and leaves the lead conceptually muddled.Chjoaygame (talk) 01:11, 10 July 2012 (UTC)
- The discussion here is characteristic of deficiencies of the whole article on heat as it stands. The article makes no distinction between 1/ heat (the kinetic energy of atoms, molecules, crystal etc. when above zero K) and 2/ the transfer (or the changes) of this energy (heat) to another place or system, a transfer which is dependent a difference in temperature.
- The article is a complete mess because it does not make a distinction between a first effect arising from absolute temperature (referenced to absolute zero) and a second effect that is quite independent of absolute zero but has everything to do with temperature differences. --Damorbel (talk) 07:30, 10 July 2012 (UTC)
Heat and Heat transfer
Chjoaygame you persist in treating heat and heat transfer as if the were the same thing, one is measured in Joules, the other in Watts (Joules per second). Do you agree? I suggest the article should make this clear, that is why I made my recent change. --Damorbel (talk) 05:43, 11 August 2012 (UTC)
- My dear Damorbel, thank you for your concern about this.
- I do not agree that heat transfer must be measured in Watt. The orthodox classical notion of heat is of an amount of energy transferred by conduction and radiation to effect a change from an initial to a final equilibrium state. The time rate of transfer, if you like, has been integrated to give a timeless quantity, measured in Joule or calorie, but it is not necessarily the case that the transfer can be represented as an integrable function of time. In non-equilibrium thermodynamics, it is common to think of heat flux measured in Watt meter−2 or calorie second−1 meter−2.
- You have an accusatory tone in your remark "Chjoaygame you persist in treating heat and heat transfer as if the[y] were the same thing, ..." As if this treatment were my private invention or my peculiar interpretation of things. The view that heat and heat transfer are more or less interchangeable concepts is agreed upon by most editors and is written into the fabric of present article and is more or less conventional or orthodox, with perhaps some latitude at times.
- Your distinction between heat measured in Joule and heat transfer measured in Watt seems likely to be a partly disguised attempt to express the idea that heat can be considered apart from its involvement in a process. Such an idea easily leads to nonsense and is foreign to the orthodox viewpoint taken by the article.
- I do not think that your recent change has the effect that you propose for it. I do not intend right now to undo your change because I do not enjoy that kind of thing, but sooner or later it must be undone.
- I have in the past found it futile to try to converse with you in detail.Chjoaygame (talk) 07:19, 11 August 2012 (UTC)
You write: "I do not agree that heat transfer must be measured in Watt".
Then say which unit is appropriate for heat transfer and which for heat, a Wiki article should be clear. --Damorbel (talk) 09:43, 11 August 2012 (UTC)
- Your present talk and editing would make it obvious to a new reader why I have in the past found it futile to try to converse with you in detail. Your conduct is damaging to the Wikipedia.Chjoaygame (talk) 02:00, 13 August 2012 (UTC)
There is already a very good Wiki article on Heat transfer, but the problem with this heat article is that it includes much material about heat transfer, which may or may not be bad. But what really is bad is a complete failure to distinguish between them.
Currently in the opening statement the article has: In physics, "heat" is by definition a transfer of energy, which completely overlaps the heat transfer article and excludes the vibrating particle (kinetic theory) aspect. Is it right to exclude kinetic theory? --Damorbel (talk) 06:36, 13 August 2012 (UTC)
Undo
I have undone the latest revision by Chjoaygame because it was made without any discussion, he(she) knows it is controversial, he explicitly refuses to recognise or respond to my arguments for clarity in the article; so his latest revision must be considered as vandalism. --Damorbel (talk) 06:42, 12 August 2012 (UTC)
Partington
You have introduced a number of references to Partington's 1949 work "Advanced treatise on physical chemistry" which is not accessible on line. More relevant to an article on 'heat' I should have thought is his other work 'A Text-book of Thermodynamics' would give a far clearer idea of his concepts on heat.
But even this other book does not give confidence as a reference. For example he has (on p61) :" A definite temperature may be assigned to any materialsystem which is in thermal equilibrium;( The temperature of the source is greater than the temperature of the refrigerator, i.e., TI > T2) Thus he appears to be a source of the 2nd law definition of temperature! (Um, the 2nd law is all about temperature difference, i.e. at least 2 temperatures; how can it therefore define a single temperature?)
Try reading Partington's book on thermodynamics, it has many strange ideas. Partington is not a good source on thermal physics. --Damorbel (talk) 12:03, 13 August 2012 (UTC)
- Thank you for this valuable historical reference and weblink.Chjoaygame (talk) 22:37, 13 August 2012 (UTC)
Undo (2)
I am about to undo the latest revision by someone with the title 'Chjoaygame'. This editor has no user page and hase made no attempt to justify his edit, thus it close to vandalism. Chjoaygame, get yourself a user page and accept that some kind of consensus i.e. a little discussion is the norm for Wiki articles. --Damorbel (talk) 05:59, 27 September 2012 (UTC)
- There is no requirement for a user to have a user page. Users are judged by their contributions, not the size of their
egouser page. HumphreyW (talk) 06:57, 27 September 2012 (UTC)
article and sources refer to closed systems
Transfer of energy as heat is customarily discussed in physics texts by reference to closed systems or bodies. An example from the present article is
- Mechanisms of heat transfer
- Referring to conduction, Partington writes: "If a hot body is brought in conducting contact with a cold body, the temperature of the hot body falls and that of the cold body rises, and it is said that a quantity of heat has passed from the hot body to the cold body."[1]
- Referring to radiation, Maxwell writes: "In Radiation, the hotter body loses heat, and the colder body receives heat by means of a process occurring in some intervening medium which does not itself thereby become hot."[2]
The article makes no attempt to consider transfer of energy as heat between open systems, in particular when diffusion is allowed between them.
The writing in the article should reflect this.Chjoaygame (talk) 07:16, 27 September 2012 (UTC)
- Chjoaygame, you write "The article makes no attempt to consider transfer of energy as heat between open systems" Why? The article is about heat, the energy of vibrating particles, not the transfer of that energy between regions with different temperatures. --Damorbel (talk) 09:37, 27 September 2012 (UTC)
- Damorbel, your comments do not address what is relevant here. What is relevant here is my edit which you undid.
- Your comment (1) is a question to me as to why the article does not attempt to consider transfer of energy as heat between open systems. This may be a reasonable question, but does not impinge on my edit, which was making more explicit that the article as it stands is about closed systems or bodies. If you want to discuss the absence of something in the article about open systems, in particular when diffusion is allowed between them, this section right here is not the place for you to do so.
- Your comment (2) is a complaint from you that the article ought to be about your idea that heat is the energy of vibrating particles, not, as it is, about the transfer of energy between bodies as heat. If you want to persuade editors to change the whole drift of the article, you may perhaps try to do so, but that is not directly relevant to my edit, which was making more explicit the present content of the article. I think, if you do try to persuade editors to change the whole drift of the article, you will encounter practically insurmountable opposition, because your idea that heat is the energy of vibrating particles is not a well defined one in physics. Thermodynamics has found that the ideas of internal energy and of entropy are appropriate instead. The ideas of internal energy and of entropy are fundamental to thermodynamics, essential to its proper understanding, and thoroughly supersede your ill defined idea of heat as the energy of vibrating particles.
- Thus your above comments are not relevant as discussion about my edit, and indeed show that your undoing of my edit was unjustified and inappropriate.Chjoaygame (talk) 08:32, 28 September 2012 (UTC)
From what you write above (...your idea that heat is the energy of vibrating particles...) I understand your argument to be that heat is not the energy of vibrating particles, OK?
In that case would you care to explain what you accept as the proper name for the kinetic energy in vibrating or colliding particles?
This is not a trivial question because it is some of this kinetic energy that is transferred between material at different temperatures. It is entirely necessary that this energy is preserved, in one form or another, during and after the transfer; were this not so the 1st law of thermodynamics would not be valid. --Damorbel (talk) 18:31, 28 September 2012 (UTC)
- Darmorbel, your comments continue to be irrelevant to the question at hand, which is about my edit. My edit is not about the questions you raise in your comments, however important and interesting they might be for some other context. My edit was making clearer and more explicit some of the points already in the article. From your comments, it continues to be evident that you have no justification for your undoing of my edit.Chjoaygame (talk) 01:20, 29 September 2012 (UTC)
Your edit is It is irrelevant to an article on heat because it woud only appliy to an article based on the 2nd law e.g. heat transfer. A proper explanation of heat has to be based on the energy contained in the motion of particles, not on the transfer of that energy between particles. It is quite possible to use examples energy transfer (diffusion collision, radiation etc.) to illustrate the fundamental definition of 'heat as the motion of particles' provided the relevance of the illustration is made clear and not used as some kind of substitute definition.
Your edit was reversed because it made no effort to clarify the distinction between heat and heat transfer, a major shortcoming in the whole article. --Damorbel (talk) 06:38, 29 September 2012 (UTC)
- Dear Damorbel, you write: "Your edit was reversed because it made no effort to clarify the distinction between heat and heat transfer, a major shortcoming in the whole article." Your demand, that an edit should make an effort to clarify the distinction between heat and heat transfer, is a wish of yours but not in general a reasonable demand on an edit of this article. That you add "a major shortcoming in the whole article" shows that your wish in this matter is more or less contrary to the consensus on which the article is currently built. Thus your reason just stated for your undoing of my edit is not a valid or reasonable one.
- Your claim, that my edit is "about whether heat transfer should be described as taking place between systems or bodies", shows that you did not carefully read or understand my edit, which is a defect of your reading, not of my edit. My edit was making it clear that the article is about closed systems or bodies, in contrast to being about open systems, as is clear even from what you write above: "It is quite possible to use examples energy transfer (diffusion collision, radiation etc.) to illustrate the fundamental definition ..."
- Your claim that my edit "woud only appliy to an article based on the 2nd law e.g. heat transfer" is muddled. The present article does accept the second law as part of its basis, and so your suggestion that my edit does not apply because the present article is not based on the second law is mistaken.
- Your gratuitous suggestions, that "A proper explanation of heat has to be based on the energy contained in the motion of particles, not on the transfer of that energy between particles. It is quite possible to use examples energy transfer (diffusion collision, radiation etc.) to illustrate the fundamental definition of 'heat as the motion of particles' provided the relevance of the illustration is made clear and not used as some kind of substitute definition", may or may not be reasonable. But they are not relevant to your undoing of my edit. My edit is making clear that the article as it stands refers to closed systems or bodies as distinct from open systems.
- Thus your comments are an expression of your many times repeatedly expressed wish to radically change the whole drift of the article as it stands at present, and may or may not be reasonable in some other context. But, for the present question, they are mistaken or irrelevant and do not provide any justification of your undoing of my edit.Chjoaygame (talk) 08:28, 29 September 2012 (UTC)
new section on usage of words
I am putting in a new section on the usage of words. Previously, a section on 'Semantics' was deleted for no clearly stated reason. There continue to be issues about the meaning of the word heat, and my current new section tries to deal with some aspects of these issues. My new section adheres strictly to the current consensus of editors of this article, but the consensus in not unanmimous. The consensus accepts the weight of opinion in present-day reliable sources.
Dissenting editors who reject this consensus like to think of heat as something that can be "stored" in a body, or like to speak of "thermal energy" as if it were a state variable, as a "part" of the internal energy. In terms of present-day physics, this dissent is irrational. I do not know how to deal happily with this dissenting rejection of the weight of opinion in present-day reliable sources. To try to make it a major part of the present article would make a hardly comprehensible mess of it, without much compensating benefit other than appeasing irrational dissent. Therefore I am just trying to state the consensus view here.Chjoaygame (talk) 06:15, 3 October 2012 (UTC)
Perhaps I should add that the present article contains inconsistencies when considered from the consensus viewpoint. Gradually we may perhaps remedy the inconsistencies.Chjoaygame (talk) 06:19, 3 October 2012 (UTC)
Chjoaygame, please check your links, the one you give does not refer to 'semantics'. --Damorbel (talk) 06:43, 3 October 2012 (UTC)
"My new section"? I'll accept 'My new edit' but nothing about the article belongs to you. --Damorbel (talk) 06:46, 3 October 2012 (UTC)
a well-known editor is currently having an unchecked field day at the article on Thermal equilibrium
I think hardly anyone watches the article on Thermal equilibrium. Because of this, I think, a well-known editor is currently having an unchecked field day there.Chjoaygame (talk) 18:54, 9 October 2012 (UTC)
who is the author of the article? note to the editor who asked that question
There is no well defined 'author of the article'. The Wikipedia works by people like you adding or subtracting bits and pieces. You were a part-author till you removed your edit.Chjoaygame (talk) 17:21, 1 October 2012 (UTC)
What is this about? --Damorbel (talk) 20:33, 1 October 2012 (UTC)
- The question was put in the article with this edit and then removed again. — HHHIPPO 20:58, 1 October 2012 (UTC)
This was simple vandalism, no need to raise it in the talk pages, there is quite enough wrong with the article already! --Damorbel (talk) 06:40, 3 October 2012 (UTC) heat is awesome — Preceding unsigned comment added by 68.177.37.202 (talk) 14:30, 10 October 2012 (UTC)
"Usage of words"
I have undone this major new section because it represents the view of one editor only, there has been do discussion of the content with other interested editors.--Damorbel (talk) 06:22, 3 October 2012 (UTC)
What is wrong with the 'undone' section:
1/ it had "heat is defined as a word that refers to....". Heat is defined as a word, only in the semantic sense.
2/ "But in strict physical terms". I think this should be 'physics'; 'physical' is not a science with 'terms', it's an adjective.
3/ "process is admitted as heating only when what is meant is transfer of energy as heat". I don't think so; surely heating is any process that causes the temperature to rise, just as cooling is any process that causes the temperature to fall; otherwise one is stuck with the concept of negative heat.
4/ "The heat transferred that leads to melting without temperature change is said to be 'latent'. How can this be true? The term latent heat was introduced by http://wiki.riteme.site/wiki/Joseph_Black#Latent_heat long before there was a satifactory definition of heat, a more accurate name would be potential energy with a clear indication as to what kind of potential energy (e.g.chemical etc.). As a scientific term latent heat is imprecise and the article should make this clear.
5/ "it would be physically improper to speak of 'heat production by friction". So friction does not give rise to heat?
6/"Occasionally a present-day author, especially when referring to history, writes of "adiabatic heating", though this is a contradiction in terms of present day physics". Adiabatic means 'without heat transfer'. It frequently refers to compression that raises (expansion - lowers) the temperature of a gas so quickly that there is no diffusion (or other transfer) of heat from outside the volume being considers i.e. the volume is insulated, adiabatic means no passage (of heat) - the opposite of diathermous
7/"nowadays one speaks of conversion of other forms of energy into internal energy." Only correct if you separate the energy arising from particle motion i.e. enegy that is proportional to temperature, only particle motion gives rise to temperature effects. --Damorbel (talk) 08:31, 3 October 2012 (UTC)
- Now :William M Connolley has reversed my deletion without any attempt to contribute to the discussion. This puts the whole matter at the school playground level (T'is! - T'isn't!). I'm sorry about this, it makes a real mess of an article. Wikipedia is a great invention but this no discussion (= mindless) behaviour can only damage the Wiki project. --Damorbel (talk) 10:52, 3 October 2012 (UTC)
- As I noted (immediately above) Wm. Connolley has reverted my deletion, making the coment "Undid revision 515749953 by Damorbel (talk) tahts a bit abrupt and not obviously necessary"
- To me Wm. C. deleted this because it wasn't obvious to him. Fair enough, William; so it is not obvious to you despite the explanation above? I get from this you did not understand the purpose of the deletion, then why not discuss this on the talk pages? The article is a lot better when it is not discussing 'usage' in the way of the deleted material. Therefore, in view of no reason being presented for restoring the section, I am deleting it again. --Damorbel (talk) 12:52, 13 November 2012 (UTC)
- Broadly all seven of these objections look wrong. And the section looks roughly correct although not perfect. It is far down the article and does not displace other more immediately useful stuff. So it should stay in. --BozMo talk 15:41, 13 November 2012 (UTC)
- Nice of you to give an explanation BozMo "Broadly all seven of these objections look wrong" But don't you think your explanation is a bit thin? Lacking in substance perhaps? I mean is "Broadly all seven of these objections look wrong" adequate? Um only the super intelligent will be able to work out which of your 8 words are relevant to the detailed argument I presented above!
- I am sorry I am struggling to find a detailed argument in your comments. Or an argument for that matter. I can see a number of assertions, all of which look broadly questionable or wrong. For example the expression "in strict physical terms" is widely used with the meaning given in the section since physical has a common meaning of "in terms of physics". Your proposal of "in strict physics terms" is an rare ungrammatical combination which as far as I can see is used only 74 times in the entire worldwide web. --BozMo talk 15:43, 14 November 2012 (UTC)
- Nice of you to give an explanation BozMo "Broadly all seven of these objections look wrong" But don't you think your explanation is a bit thin? Lacking in substance perhaps? I mean is "Broadly all seven of these objections look wrong" adequate? Um only the super intelligent will be able to work out which of your 8 words are relevant to the detailed argument I presented above!
I suggest you improve your contribution or withdraw it. --Damorbel (talk) 15:55, 13 November 2012 (UTC)
What about convection?
Convection, in itself is not conduction nor radiation... --201.204.200.18 (talk) 02:49, 13 November 2012 (UTC)
See http://wiki.riteme.site/wiki/Convective_heat_transfer --201.204.200.18 (talk) 02:52, 13 November 2012 (UTC)
- Physics uses a technical definition of heat as energy in process of transfer by conduction or radiation. This is not the ordinary language usage, nor is it the loose usage that is found in natural science writings when the strict technical definition is not being attended to. As it happens, only for some special real world processes can the notion of heat conduction be uniquely defined, and for the general case, diffusion makes it impossible to define conduction uniquely. As a result, transfer of internal energy calls for an account that relies on the concept of entropy as well as on the concept of energy, as was worked out by Gibbs.
- 'Convection of heat' is a term that falls into the area of ordinary language or loose usage, and is not admitted by the strict technical physical definition of heat transfer. The strict technical physical definition requires that one should speak of 'convection of internal energy'.
- The reason for this is that, in the thermodynamic conception, internal energy consists of microscopic mutual and internal potential and kinetic energies of the particles of the material of the body of interest. The split into kinetic and mutual and internal potential energy is not unique, but depends on the process contemplated for defining the split. Inextricably linked with this is that the internal energy of a body cannot be split uniquely into a work component and a heat component, because again the split depends on the process contemplated for defining the split. The outcome is that heat transfer can be uniquely defined only by specification of the path of the process of transfer. Thus heat transfer is essentially a process concept, while there is no unique definition of a state variable of heat content. In ordinary language, one might say that heat is not an enduring substance. For the same reasons, the phrase "thermal energy" is a loose usage but does not refer to a uniquely defined physical quantity. In ordinary language, thermal energy is not an enduring substance. In ordinary language, one might use a metaphor and say that heat and thermal energy are moveable feasts.
- This presents a practical problem for the Wikipedia, because there needs to be some reconciliation between the ordinary language usage and the strict technical usage. The current consensus solution in the Wikipedia is to say explicitly and deliberately that the articles use not the ordinary language or the loose usages, but strictly follow the strict technical physical definition. There are some dissenting voices from this consensus. Mostly, dissenters seem to lack comprehension of the reasons for the strict technical definition, but they do not see themselves as lacking such comprehension.
- I am not familiar with the engineering literature, but I have an impression that engineers sometimes or often follow the loose usage that confounds heat content with internal energy, in effect, in loose agreement with the ordinary language usage. So they speak of convection of heat. I think they also speak of "thermal energy" as if it were a well defined quantity. They are practical people.
- As school children, we were taught that heat is transferred by conduction, radiation, and convection. As school children, we were not taught thermodynamics, and we did not learn of the concept of internal energy.
- It would be devastatingly complicated and confusing to try to word the Wikipedia articles so as to express, alongside one another at every step, both the ordinary language and loose usages, and the strict technical physical definition.
- Those who prefer the ordinary language usage will have native facility in translating the strict technical physical definition into ordinary language, but very few readers will have the skill to consistently translate from ordinary language to strict technical physical definition usage. The current Wikipedia editorial consensus undertakes to consistently supply and apply the results of such skill.Chjoaygame (talk) 06:57, 13 November 2012 (UTC)Chjoaygame (talk) 07:03, 13 November 2012 (UTC)
- 201.204.200.18, I would prefer to reply to a name, will you help?
- Chjoaygame, yet another example of where you theory of 'heat' as 'transfer of energy' (which should be heat transfer) breaks down.
- For example you write:-
- "'Convection of heat' is a term that falls into the area of ordinary language or loose usage, and is not admitted by the strict technical physical definition of heat transfer. The strict technical physical definition requires that one should speak of 'convection of internal energy'."
- Convection can only take place in a system not in equilibrium in a gravitational field (let us not get into discussion of forced convection which is related but has many complicating variables).
- So what part of 'internal energy' is gravitation?
- If you wish to examine the matter further I suggest you read the Wiki article on the Navier–Stokes equations.
- As soon as you abandon the concept of heat as the kinetic energy in microscopic (i.e. indivdual particles) you will not find coherent explanations of thermal phenomena such as convection. --Damorbel (talk) 08:35, 13 November 2012 (UTC)
- Statistical mechanics explains classical thermodynamics, it does not replace it. Classical thermodynamics makes no reference to the particulate nature of matter and is a theory that is complete. It uses measurements of e.g. specific heat, whereas statistical mechanics explains the results of those measurements in terms of a particulate theory of matter, but classical thermodynamics is not at a loss to predict the macroscopic results of an experiment couched in macroscopic variables. Einstein said "A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content which I am convinced will never be overthrown, within the framework of applicability of its basic concepts." He was NOT talking about statistical mechanics, he was talking about classical thermodynamics. The Navier-Stokes equations make no reference to particles nor particle velocities. They use only macroscopic variables (pressure, velocity, etc.) They and all of classical thermodynamics may be derived from statistical mechanics, but if ever a statistical mechanics theory disagrees with classical thermodynamics, then that statistical mechanics theory is wrong. Its fine to treat the two as a combined theory, bouncing back and forth between the two, when working on a particular problem, but when doing theoretical work, one should really maintain the distinction between the two. See the introduction to http://www.e-booksdirectory.com/details.php?ebook=4226 PAR (talk) 15:52, 13 November 2012 (UTC)
http://wiki.riteme.site/wiki/Rayleigh%E2%80%93B%C3%A9nard_convection --201.204.200.18 (talk) 20:42, 13 November 2012 (UTC)
http://books.google.co.cr/books?id=pJaiReRZvHMC&printsec=frontcover&dq=convection+fluid+flow&hl=es&sa=X&ei=17CiUMXzKYSu8ASP5YC4BA&ved=0CC0Q6AEwAQ#v=onepage&q=convection%20fluid%20flow&f=false --201.204.200.18 (talk) 20:47, 13 November 2012 (UTC)
- PAR what do you mean when you write "Classical thermodynamics makes no reference to the particulate nature of matter"? What then does N (Avogadro's number) refer to in the gas laws? Or can you explain the meaning of Molar form without mentioning particles. Thermodynamics without particles, absurd! --Damorbel (talk) 21:36, 13 November 2012 (UTC)
- Avogadro's number is not a part of classical thermodynamics. PV=Nkt is an equation of state expressed in statistical mechanics terms. In classical thermodynamics its PV=mRT/λ where R is a universal constant m is mass and λ is a constant which must be measured for each material. It was discovered that e.g. the λ of oxygen gas was very nearly 16 times that of hydrogen gas. The particulate theory of matter explains this by saying each molecule of oxygen is 16 times the mass of a molecule of hydrogen. Not exactly right says classical thermodynamics, but that's the particulate theory's problem, not classical thermodynamic's problem. Particulate theory has to improve by dealing with isotopes, etc. Classical thermodynamics is based on macroscopic measurements, it is a phenomenological theory, and it has always given the right answer, it doesn't deal with particles, and it doesn't have to. If the particulate theory falls short, that's not classical thermodynamic's problem. Don't get me wrong, I would not think of dealing with a problem in purely classical terms except to understand pure classical thermodynamics, but if you run into problems, its either because A) you don't understand classical thermodynamics or B) you don't understand particulate theory/statistical mechanics, or C) particulate theory/statistical mechanics is not up to snuff. (Fourth possibility - classical thermodynamics is wrong and you win the Nobel prize and become famous). See the explanation just below this. PAR (talk) 05:14, 14 November 2012 (UTC)
- PAR you write:- "Avogadro's number is not a part of classical thermodynamics." Really? Then you write "PV=Nkt is an equation of state expressed in statistical mechanics terms." And you are maintaining this eliminates the role of particles? You then cite PV=mRT/λ as an example of thermodynamics without particles. What, then, do you think R is all about, where ? That is to say: NA = R/kB. You make it worse by not recognising that your k (= kB) is the Boltzmann constant, which is the energy per particle for each K (Kelvin) --Damorbel (talk) 09:26, 15 November 2012 (UTC)
- Classical thermodynamics is actually known to be wrong, the statements it makes are only valid in a statistical sense. The second law as formulated in classical thermodynamics is false, the entropy of isolated systems can spontaneously decrease; this has been observed in experiments and the observations are consistent with the predictions of the fluctuation theorem.
- One can still argue that thermodynamics is universal, many of the laws are independent of the microscopic model, so in this respect, statistical mechanics is not more fundamental. But then I would say that this occurs in most of physics. If you wouldn't have emergent laws at higher levels then we would not have made much progress in science. The laws of classical mechanics are is a sense universal, this allowed Newton to discover these laws without him having to figure out all the details of superstring theory first. Count Iblis (talk) 18:40, 14 November 2012 (UTC)
- Count Iblis makes a fair point. As I interpret things, classical thermodynamics has a range of applicability, and it shouldn't be applied outside that range, because outside that range it isn't applicable. Within that range it has a degree of universality, which sometimes leads people to say that it is universal, punto. No, not universal punto, but "universal" only within a limited range of applicability. It takes some effort to remember to define that range.Chjoaygame (talk) 06:14, 15 November 2012 (UTC)
- Count Iblis writes "Classical thermodynamics is actually known to be wrong,". Just what do refer to when you assert 'thermodynamics is known to be wrong'?
- This statement, made without any support, is quite characteristic of the defects of the Heat article. Not having any support it is simply a wild assertion that occupies space without contributing anything. Count Iblis, your contribution is through and through useless; "statistical mechanics is not more fundamental", what does this mean? Can you measure degress fundamentalness? Please, will contibutors not contaminate talk pages with vague statements and remarks about the contributors instead of the contributions. --Damorbel (talk) 09:26, 15 November 2012 (UTC)
Actually the general laws of thermodynamics were developed with regard to the concept of system, not with regard tho the concept of particle. Statistical thermodynamics was a later concept that was developed in order to establish relationships between microscopic properties of particles and the general theory, but statistical thermodynamics is not fundamental to the general laws of thermodynamics: actually different forms of these laws apply in the definition of entropy as an aspect of information in information physics, per example. Statisical mechanics was started around 1870. Carnot published his works around 1824. Rankine published his textbook around 1850. Around 1850 Rankine, Lord Kelvin and Clausius established the first and second law of thermodynamics and most of the fundametal aspects of this science (before the concept of statistical thermodynamics related these concepts, in some aspects, to the microscopic properties of particles). When one studies the thermodynamics proposed by Gibbs one does not deal much into the aspects of how microscopic particles behave. It is true that Avogrado's proposition regarding the number of particles in a gas and it's volume dates from 1811, but it is not fundamental in defining the laws of thermodynamics as such. The value of the Avogadro's constant started to be established by 1865. When Milikan measured the charge of the electron in 1910 it was easier to establish the value of the constant. Perrin proposed the measure with regard to O2 in 1909. Gibbs work was published between 1875 and 1878. Clearly the general laws of thermodynamics were established without the contribution of statistical mechanics and without regard to the microscopic components of the system. They stem from abstract thought and experimentation and have been able to withhold the passage of time: even at the quantum level and the general theory of relativity level and the information theory and information physics theory they seeem to still apply, albeit with different formulations. But heat and heat transfer are not "thermodynamics", they relate to the emission of radiaton between 2 bodies at different temperatures, the conduction of heat when two bodies are in physical contact on a macroscopic scale, which relates to the "vibration" and "kinetic energy" of atoms, if I understand correctly, and, if I understand correctly, in fluids (whether it is plasma on the Sun, air on the atmosphere, etc.) by the convection (movement of larger masses of fluid). In fluids we have the problem that the equations we use to model the system (Navier-Stokes) are not mathematical proven to be exist and be smooth in a generalized form. This implies problems specially in turbulent flow (which is where convection is more important). Convection and fluid phenomena are studied in chemical engineering as "transport phenomena" where problems related to heat, mass and momentum transfer are dealt with in conjuction. (see: http://wiki.riteme.site/wiki/Transport_phenomena). "In engineering and physics, the study of transport phenomena concerns the exchange of mass, energy, and momentum between observed and studied systems. While it draws from fields as diverse as continuum mechanics and thermodynamics, it places a heavy emphasis on the commonalities between the topics covered. Mass, momentum, and heat transport all share a very similar mathematical framework, and the parallels between them are exploited in the study of transport phenomena to draw deep mathematical connections that often provide very useful tools in the analysis of one field that are directly derived from the others. Generally speaking there is a current ongoing philosophical debate about a theory of everything that should encompass all phenomena." --201.204.200.18 (talk) 22:15, 13 November 2012 (UTC)
Also see: http://wiki.riteme.site/wiki/Rayleigh_number
--201.204.200.18 (talk) 01:09, 14 November 2012 (UTC)
- Editor 201.204.200.18 and Editor PAR write well above, in close agreement about the fundamental distinction between thermodynamics proper and statistical mechanics. I think they represent the overwhelming consensus of Wikipedia editors on that, and in general I accept that consensus. There are some dissenting voices. It is not easy to see how to satisfy the dissenters.
- Editor 201.204.200.18 writes of "a theory of everything that should encompass all phenomena". I think we are not there yet, and that we should not try to write as if we are nearly there.
- Editor 201.204.200.18 writes: "But heat and heat transfer are not "thermodynamics"..." It is true the heat and work are not the fundamental concepts of Gibbs' presentation. Gibbs' thermodynamics is especially intended to deal with open systems, for which heat and work are in general not uniquely defined. But Gibbs does rely on the concept of absolute or thermodynamic temperature. This is determined by considering special cases, namely closed systems, for which heat and work transfers can be uniquely defined. In this sense, heat transfer is essential to thermodynamics.
- Editor 201.204.200.18 cites some engineering writing that speaks of heat when a strict technical physical definition would speak of internal energy. This is a problem for us here. May I repeat what I wrote above:
- It would be devastatingly complicated and confusing to try to word the Wikipedia articles so as to express, alongside one another at every step, both the ordinary language and loose usages, and the strict technical physical definition.
- Not all engineers consistently follow the ordinary language usage as contrasted with the strict technical physical definition. Engineers are practical people.
- The term "internal energy" does not appear in the Wikipedia article Transport phenomena cited above by editor 201.204.200.18. This is a signal that the article is hardly about thermodynamics, and that the distinct thermodynamic concept of internal energy is not important for that article. This is not out of line. Many transport phenomena can be well considered without reliance on thermodynamics as such. I suppose that article was largely written by engineers, or by physicists with interests in statistical mechanics. In statistical mechanics, one also finds that mostly the word heat refers to what a thermodynamicist would call internal energy. This is because it is only in special problems that there arises the need for words to make explicit the distinction, between a process of transfer of energy as heat, and the internal energy of a body in a particular state. Nevertheless, it is not possible to give a consistent account of thermodynamics without careful distinction between those two concepts. Again I say that it would be devastatingly complicated and confusing to try to word the Wikipedia articles that refer closely to thermodynamics so as to express, alongside one another at every step, both the ordinary language and loose usages, and the strict technical physical definition of heat. For myself, I just avoid trying to edit articles that seem to have the ordinary language usage thoroughly established within themselves. An insistence that the ordinary language and engineering usage should prevail throughout, or that a mixture of terms should be accepted throughout, would cripple the Wikipedia in specific reference to thermodynamics.Chjoaygame (talk) 04:23, 14 November 2012 (UTC)
Chjoayme misundertands some basic facts. Probably he is not well versed in physical chemistry and heat transfer. Heat transfer is a discipline that deals with the transfer of energy as heat between different systems. Heat is transfered by three different phenomena (radiation, convection and conduction). Convection has not been reduced to the other two. There are specific dimensionless numbers that deal with the situation of wether, in a fluid, conduction of convection dominate (Rayleigh Number). I would agree that "heat transfer" and "heat" should be treated separetly, one being a fundamental aspect of the first law of thermodynamics and it's may interpretations and the other being related to the mechanistical aspects of heat transfer. The wiki's article on Transport Phenomena might not talk about enthalpy, but enthalpy and entropy are an important part of the study of Transport Phenomea. A peak at the literature would be enough. I do think that articles on thermodynamics should encompass the wide variety of concepts that curren--186.32.17.47 (talk) 16:26, 14 November 2012 (UTC)tly are involved in the subject, where there are different perspectives and that articles on thermodynamics should be more about current physics thought and not about other subjects. i.e. "heat transfer" and work in a mechanistical sense might be better of in articles proper to that subject, as engineering perspectives on the subjects that should be present on engineering topics not on physics topics. --186.32.17.47 (talk) 16:03, 14 November 2012 (UTC) I might not have made myself clear: when I talk about "heat transfer" I am talking about the _discipline_ related to the study of the transfer of heat; which of the different forms of heat transfer prevails in a given case, how is heat transfered, the _dynamics_ of it. That discipline is not centered around thermodynamics, altough how "far"· the system is from a thermodynamic equilibrium is important. The point I am trying to make, if it accounts for anything, is the difference in the disciplines of "heat transfer" and, in general "transport phenomena" and thermodynamics. This article (an article about "heat") is, I believe, an article _about_ _thermodynamics_ whereby, the article on "heat transfer" deals with that subject. Still I sustain that, if one is going to mention "heat transfer" convection and advection are important and should be considered as part of the forms of "heat transfer". If one reads the article on "heat transfer" it is inconsistent with the article on "heat" regarding the different mechanisms of "heat transfer". That is, more or less, what started this discussion. the mechanism of convection might make it difficult to establish, in a thermodynamic sense, what work is being done inside the system, how enthalpy moves in the system, etc. This is complicated by the limited applicability of the framework for fluid dynamics (Navier Stokes existence and smoothness) when there is turbulent flow of a compresible fluid. As it says in "http://wiki.riteme.site/wiki/Turbulent_flow" Nobel Laureate Richard Feynman described turbulence as "the most important unsolved problem of classical physics."[1]. I do believe the distintion between "heat" and "heat transfer phenomea" might be established in the article so as to not confuse the reader of both articles ("heat" and "heat transfer"). The concept of what is _heat_ in the physical thermodynamical sense and what is studied under "heat transfer" could be clarified so as not to confuse the reader. I do appreciate a lot Chjoaygame detailed description above on convection and how it involves different concepts (work, heat and internal energy) and why relating this to "heat" could bring confussion.--186.32.17.47 (talk) 16:26, 14 November 2012 (UTC)
- There is no reason even to bring up the mathematically complicated natural/free convection when forced convection (the common type that happens in car radiators) works just as well as illustration. Chjoaygame is technically and perfectly correct that only internal energy (not heat) can be advected as a bulk flow of matter containing energy within it and moved from here to there. That means heat pumps don't really pump heat but rather energy. Heat cannot because heat cannot be stored in matter since the amount of it there, cannot even be defined! If you can't put a number on it, you can't claim it's "real ".
Temperature and thus kinetic energy may play only minor roles in this, when energy of phase transitions is involved. For example water can be turned to steam and sent down a pipe to transfer energy by condensing somewhere else, and yet the temp changes are very small-- as small as you like for a given transfer. They are markers for direction of transfer but cannot be used to quantitate how much energy is moved. That's a clue that they aren't fundamental and are in no way the core of what is happening physically. Physically it is potential energy being moved, not unlike moving a charged battery from here to there. It actually has nothing to do with "heat" in a thermodynamic sense.SBHarris 18:46, 14 November 2012 (UTC)
Actually a "heat pump" _is_ a thermodinamic cycle that involves doing work in order to transfer heat from a colder body to a hoter body. Just see http://wiki.riteme.site/wiki/Heat_pump. THe Navier-Stokes equations are the equations used that describe motion in a fluid: it does not matter if flow is laminar or turbulent, if there is forced convection or natural convection involved at some point. In both the use of dimentionless numbers arise, in order to describe weather flow is laminar or turbulent. Such numbers as Reynold's number arise in forced convection and Grashof's number in natural convection. Of course the ammount of heat transfered from the heat source to the heat sink _is_ computable and computed all the time. Heat transfer is not a matter of temperature (heat is transfered isothermaly all the time. In Carnot's cycle heat is transfered isothermaly and work is done isentropicaly). See http://wiki.riteme.site/wiki/Carnot_cycle. SBharris might be well intended but he has deep confusions in regard to thermodynamics, temperature, heat, "heat transfer" and the like: this is clearly not his filed of expertise. --201.204.200.18 (talk) 22:50, 14 November 2012 (UTC)
Also see: "Convective heat transfer, often referred to simply as convection, is the transfer of heat from one place to another by the movement of fluids. Convection is usually the dominant form of heat transfer in liquids and gases. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of conduction (heat diffusion) and heat transfer by bulk fluid flow, a process technically called heat advection." http://wiki.riteme.site/wiki/Convective_heat_transfer#Newton.27s_law_of_cooling I do understand that Heat "in a thermodynamic sense" is one thing and the discipline of the study of "heat transfer" in a mechanistical way are different things. What I am pointing out is that _it_might_ be called for to clarify that, in the article on heat it says "In physics, there are two kinds of thermal interaction that account for heat transfer: conduction,[4] and electromagnetic radiation.[5]" But the link to heat transfer reads "Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy and heat between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system.". So the "heat transfer" that is been refered in this article on heat, and the "discipline" of "heat transfer" that is being refered to in the other article seem to be _different_ things. --201.204.200.18 (talk) 00:02, 15 November 2012 (UTC)
- Editor 201.204.200.18 writes: "the "heat transfer" that is been refered in this article on heat, and the "discipline" of "heat transfer" that is being refered to in the other article seem to be _different_ things". Yes, I think that is fair comment.Chjoaygame (talk) 06:07, 15 November 2012 (UTC)
engineering and physics and chemistry article in Wikpedia
There are many ways in which the word heat is used. In ordinary language it has a very diverse range of meanings. In technical writings in natural sciences and engineering there is still a range of meanings. Different fields use the word differently. The acute problem here is that there is a difference in usage between engineering and physics. In the strict physical technical definition, heat is a process word, not a state word; to put it in ordinary language, in the strict physical definition, heat is not a substance that might be transported by convection. In the usage of many but not all engineers, the word heat does duty also for internal energy in the context of convection. Some Wikipedia articles are written with the (non-universal) engineering usage that says that heat can be convected, which also agrees with ordinary language. Some Wikipedia articles are specifically concerned with thermodynamics, and they would be crippled if forced to accept the (non-universal) engineering usage. In thermodynamics, the distinction between heat and internal energy is fundamental and calls for ready access to a customarily accepted and logically rigorous terminology. This kind of distinction is not so urgent for engineers, who are practical people who know intuitively what they are talking about without depending on a rigorously logical terminology. I am not familiar with the engineering literature, but I have observed that to some extent engineers seem to differ in how they talk about such matters. I don't know what is the background of editor 201.204.200.18, but it is clear that he is of the school of thought that it is proper to say that heat can be convected, and it seems that he thinks that those who find that language not convenient for thermodynamics don't know what they are talking about.
It is hard to find solutions to such problems. One solution would be to let each article announce clearly its own frame of language, without insisting that all Wikipedia articles accept the same frame of language. To some extent that is the situation that prevails at present. Editor 201.204.200.18 cites Wikipedia articles that accept the usage that heat can be convected, and he speaks of the discipline of heat transfer. Evidently the users of those articles are not troubled by the concerns of logical rigour that concern some thermodynamicists. I suppose those users are practical people. But some Wikipedia articles find inconvenient the usage that heat can be convected, and such articles use the strict technical physical definition, which carefully distinguishes heat from internal energy. I do not try to edit the articles that thoroughly accept the usage that heat can be convected, because I don't think it would be useful for me to do so. Editor 201.204.200.18, as I understand him, is suggesting that the articles that currently do not follow that usage should think about changing so as to follow it in future. I have repeated my view that for articles with a strict thermodynamic concern, to follow that usage would be damaging.Chjoaygame (talk) 00:20, 15 November 2012 (UTC)
I have now made an edit, which is probably overkill, but might be a start to resolving this problem?Chjoaygame (talk) 00:42, 15 November 2012 (UTC)
- I find myself in the odd position of arguing against the same point of view that I myself held a couple of years ago, and that you talked me out of. So I'm playing St. Paul here, preaching the new gospel to the unconverted. But I used to be a persecutor of that new point of view. Sigh.
Looking at it from the point of view that heat and work are not state variables, but a state variable change is only the sum of them (the change in internal energy is due to the sum of work and heat), I find it a little sweet and naive how people just imagine that objects "contain" a given amount of heat. Or thermal energy. They don't. Objects contain energy, but one cannot say how it got there. It could be any combination of work and heat (many paths) and you'd have the same object at the same temperature, and could tell nothing about its past. So how could you imagine you could recognize how much heat it took to get there? And that you can know what that amount is (therefore) contained, NOW?
And that when you transfer that energy, using the object as an advective vehicle, you can say you transfered heat when you transfered the object (as happens in convection). And that in heat pumps, the heat you transfer is the SAME heat, which is what the idea of "transfer" suggests.
It's sort of like the guy who puts money in the bank and does a wire transfer to somebody else in another state, and they get money, and the first guy is convinced that the money the other guy gets at Bank#2 is the SAME currency that went in the other end, at Bank#1. He's convinced that there is something special about the bills he put in. So that even if the guy at the other end gets more, due to some bank error, the first guy will be convinced that he got some extra bills of the bank's PLUS the first guy's bills.
In thermo, there's a conservation law for energy, but none for heat. So heat is like $100 bills that can be turned into other types of money. It can be transfered, but most interesting money transfers don't transfer driving around currency (physical notes) in an armored car, but rather 1's and 0's that are generated by (converted from) currency with name-attached at my end, and then get turned back into currency with somebody's name attached, at the other end.
Take a heat pump. It need not involve a phase change. A simple heat pump has a gas absorb heat from a cold reservoir, then you do work on it to raise the temp, and run it past the exchanger at the warm reservoir, where it dumps energy as heat because it's hotter than the warm reservoir. Then you let it expand until it's colder than the cold reservoir, run it back to the cold reservoir to absorb more heat, and repeat. You convince yourself that you're transporting heat from cold to warm, even though some extra heat appears at the warm due to your work (which you pretend has been transformed into heat). But that view pretends that heat is some "thing" that can't be created or destroyed. You're transferring energy (money) not bill and coins (work and heat)!
You can do endless variations. Suppose I compress a gas in a cylinder until it gets adiabatically hot, then transport it across town and extract the same work I put in, as an adiabatic reversible process. It his "heat transfer" just because the gas is hot during transport? I never put heat in, and I never pulled heat out, so how can I be transferring it? I think it would be better to call this "work transfer," not heat transfer! ;). If you don't believe a substance can have "thermal content" that is definable, then heat pumps don't even have heat at some point in their cycles, since all they transfer is fluids and gases containing internal energy, which is like money-- an intangible. No heat exists in them. The heat is gone. Heat is like currency-- it exists at one end of a wire transfer and also the other end, but in between, it's 1's and 0's. Still money, but not currency. It's money transfer, not currency transfer. SBHarris 03:14, 15 November 2012 (UTC)
- For sticklers for grammar, one can happily say, I think, that, between closed systems or bodies, energy is transferred as heat and as work. It is but a short step from there to speaking of heat transfer. Perhaps a dangerously short step?Chjoaygame (talk) 04:24, 15 November 2012 (UTC)
It's easy to define heat transfer-- that's just heat. Not so easy is heat content (thermal energy). If no work is done you can "pretend" that all change in internal energy is thermal energy, like it was stored as "heat". This does no harm. But when work is done, it's bad. It takes less heat to raise the temp of a gas sample at constant volume than at constant pressure . When you get done you can let the constant volume one expand freely doing no work to the same volume as the other. Now you have identical samples but put more heat into one than the other. You cannot tell a sample's heat content from its state. It isn't how much heat you put in to warm it because this is variable (some got tapped off one sample as "work" here). Thermal content is an imaginary thing if you think it's related to heat input. The minimum possible input is just the internal energy change so why not just call it that (energy change) and leave "thermal energy change " to the boneyard.SBHarris 18:55, 15 November 2012 (UTC)
From what I can gather I agree with Chjoaygame: the notion of "heat" in the rigorous physical and thermodinamical sense is _one_ thing. What in (mostly engineering and some applied physics and chemistry: physical chemistry) is regarded as "heat transfer" is another thing. "heat transfer" is a "discipline" in as much as it _is_ a topic in engineering and some applied science. I studied Chemical Engineering back in the 90's. We did take a couple of years of physics, more or less 4 years of chemistry, including physical chemistry, a year of thermodynamics, a semester of transport phenomena, a semester of heat transfer, a semester of fluid dynamics, a semester of chemical reaction engineering, a year of mass transfer, about a year of chemical engineering design courses, among other things (calculus, linear algebra, differential equations, statistics, and the like). That is from where I heat the concept of "heat" in a thermodynamic point of view (mostly classical thermodynamics altough we did study some statistical thermodynamics also) but also of "heat transfer" as distinct discipline, in as much as engineering mechanics is a distinct discipline. Of course the concepts studied in the study and behavior and design of equipment in "heat transfer" are not _the_same_ as the rigourous definiton of "heat" in thermodynamics. Actually that is the main point that can be gather from the distinction. It is true that in a matter so complex as "convection" where different concepts are at play at the same time (the movement of the fluid as it absorbes energy, increases it's temperature, reduces it's density and moves, forced convection, heat conduction, even radiation that might be transmited within particles of the fluid) is _simplified_ in engineering in order to be able to _design_ equipement. Thus, the discipline of the study and _design_ regarded as "heat transfer" is distinct from the concept of "heat" in thermodynamics; similary as the notion of, i.e, fluid dynamics and the design of equipment is distinct from the concepts related to "work" and "enthalpy" and "internal energy" from thermodynamics, or even the rigourous study of mechanics in _physics. But I also would point out that turbulent flow (where "convection" usually is more important than "conduction"), specially where fluids are compressible and even more where they are not newtonian. The Navier-Stokes equations are not proven to be smooth or even to have solutions in all cases. This kind of situation makes the study of the mechanics of mass and heat momentum transfer specially complicated in these instances. I do not think, at all, that "it is proper to say that heat can be convected, and it seems that he thinks that those who find that language not convenient for thermodynamics don't know what they are talking about" I actually quite agree with Chjoaygame in what I understand of what he is writing. My _only_ point was that this difference of concept between what is studied under the discipline of "heat transfer" and what "heat" is on a thermodynamic sense _are_ different things. I also find his writtings above quite deep and interesting (for what that matters, even if it is not the main point of the wiki, they have made me a little bit wiser in regards to thermodynamics). In regards to Sbharris argument that one can´t calculate the ammount of heat that is being released in a process: there are different ways to calculate this variable. It is not true that only variables of state can be calculated. i.e. the ammount of work done is the _path_ integral of a force through a distance (δW=F●vδt). With regard to "heat", the amount of heat transfered through conduction can be calculated by Fourier's law (http://wiki.riteme.site/wiki/Thermal_conduction)
where (including the SI units)
: is the amount of heat transferred per unit time (in W) and |
: is an oriented surface area element (in m2)
In the case of radiation see (http://wiki.riteme.site/wiki/Thermal_radiation). Of course that, for a given process, if one has the functions of state for the system previously defined for two equilibrium states and has the ammount of work done one can use the first law of thermodynamics to calculate the ammount of heat. Since, i.e. δW=F●vδt and dE=δW+δQ one can calculate the ammount of heat. E is a function of the state of the system (it's position in gravitational or electromagnetic fields, i.e, it's kinetic energy, i.e., temperature, pressure...) if the effect of the force is known work is known. Only solve for Q. In the case of the heat pump there is an ammount of energy transfered from the sorroundigs to the system in one end that _is_ calculated and an ammount of work provided to the system that _is_ calculated. Thus, by the first law of thermodynamics, heat rejected to the heat sink is basically (ideally) the ammount of heat extracted from the heat source plus work done on the system, on each cycle. I really don't see the point or understand the reason for the comparissions of thermodynamics and money transfers. They do not make sense to me: heat, heat transfer, work, etc. are not "like" anything else, they are what they are. What the first law of thermodynamics states is that energy is conserved and it is transfered by one of two "transfer quantities" work or heat. The total change of energy of the system is _equal_ to the ammount (net) work done by the sytem plus the ammount of (net) heat released from the system. Energy is a function of the _state_ of the system. Work is a a scalar quantity that quantifies energy used when a force is applied through a distance (function of the path, not the state). Heat is a scalar quantity that cuantifies energy dispersed by the system that is not used to perform work. The second law of thermodynamics defines de minimum ammount of heat that must be dispersed in a change in the state of a system (TdS). Equivalenty the first law "forbids" perpetual motion of the first kind and the second law "forbids" perpetual motion of the second kind. I do not know where SBHarris gets the idea that functions of path can't be calculated and functions of state can. All of mechanics deals with _calculations_ mostly related with functions of _path_ (not state). There are also mechanistical calculations regarding heat as Fourier's law, heat equations, convection-diffusion equations, newton's law of cooling (which is a special case of fourier's) and radiative heat transfer. — Preceding unsigned comment added by 201.204.200.18 (talk) 19:36, 15 November 2012 (UTC)
naughty, naughtyI won't get into the article on thermal energy, but I think I have a naughty, naughty own research synthesis idea about it. There are two genera of characteristic functions, the thermodynamic potentials, and the Massieu-Planck functions. The thermodynamic potentials may be regarded as the internal energy and certain of its Legendre transforms, as functions of their natural variables. In a sense, these are all 'thermal energies', and when people speak of thermal energy they seem to me to be referring implicitly or tacitly or vaguely to some or all of these energy functions, not wanting to bother to think out which. The point is that 'thermal energy' can be thought of not as a particular or specific quantity, but as a genus of characteristic functions. This I think makes some sense of the usage, but I have not seen any hint of this thought in the literature. It is truly naughty, naughty.Chjoaygame (talk) 13:53, 15 November 2012 (UTC) Waleswatcher's current round of editsI disagree with Waleswatcher's current round of edits. The present problems of the article are largely due to the defects of his previous round of edits, which his current round of edits is more or less restoring. Waleswatcher seems to think he can edit at his whim, disregarding the views of other editors and not bothering with what appears in the talk page. He seems not to understand the questions at issue.Chjoaygame (talk) 16:11, 15 November 2012 (UTC)
Now, in _thermodynamics_ heat is a transfer quantity when there is a gradient in temperature. "heat" is not contained in any substance, in as much as work is not "contained" but exerted upon a system. There is a _confusion_ between "heat" and "thermal energy", thermal energy being internal energy dependant on temperature. The problem is that it is imposible to distinguish the different "kinds" of internal energy contained in the system: what one knows is that the system has a possibility of accumulating energy that is usually a function of temperature. i.e. an isothermal phase transformation within the system would not affect it's temperature. — Preceding unsigned comment added by 186.32.17.47 (talk) 16:13, 19 November 2012 (UTC) The state of the Heat articleIt should be made clear that there are many mistaken contributions to the various Heat articles (Thermodynamics etc.) and their discussion pages trying to present thermal physics as sommehow 'unconnected' to the energy of the individual particles making up a (thermal) system. This would indeed make quite funny joke if Wikipedia was not seen by most people as a valuable work of reference. If thermal physics is to reject the 'energetic particle' nature, then atomic theorywill have go with it. It was only when, 88 years later, Einstein linked the (Brownian) motion (1827) of pollen grains with the thermal motion of molecules (in one of his 1905 papers) and Marian Smoluchowski (1906) brought the solution of the problem to the attention of physicists, and presented it as a way to indirectly confirm the existence of atoms and molecules. Their equations describing Brownian motion were subsequently verified by the experimental work of Jean Baptiste Perrin in 1913. The (energetic) movement of particles may well be free, as in a monatomic gas; it may be partially constrained as with the motions of molecules when the energy may be in rotational dipole motions; in weak bonds as in liquids or strong bonds as in solids e.g. crystals. The energy in these bonds is released when the bonds are broken. This energy is generally called latent heat which can be misleading since bond energy does not involve motion, that is why solids are solids! The (average) position of particles in a solid is fixed, that is why solids are solids! But in their fixed (relative) positions the particles have mass and their thermal energy causes them to vibrate when they exchange their kinetic energy with the (elastic; potential) bond energy that holds them in place. The particles of solids have multiple bonds holding them in place and the energy of particles is shared by the forces along these multiple bonds, that is one of the ways heat is transmitted in solids) check with Phonons. So please, contributors, take these fundamental facts of atomic theory of matter into account when contributing to therml articles in Wikipedia and let us get rid of the errors and verbal pap in the current articles. --Damorbel (talk) 07:28, 16 November 2012 (UTC)
There are two concepts at interlpay here: one is the general theory of equilibrium thermodynamics. The other is it's concordance with the macroscopic effects of microscopic particles. i.e. there is "entropy" in the study of information systems, in informational physics, in gravitational aspects of nature, but we do not have, as of yet, a theory that unifies a theory of gravitation with quantum mechanics. What is _wrong_ is to claim that the theory of thermodynamics _requires_ or _is_based_upon_ statistical mechanics. It was developed well before statistical mechanics and the relation of both was established afterwards. If one is to believe that, according to all human experience, the laws of thermodynamics hold this does not have much to do with wether statistical mechanics hold. Of course if statistical mechanics hold true and they _contradict_ the laws of thermodynamics then these laws would cease to be general laws of the universe. But, up until know, quantum theory, the general theory of relativity, information theory, information physics, all seems to agree with the generalizations made by thermodynamic equilibrium theories, well before the other theories came around. We still have to see what dark matter, dark energy and other aspects of the universe hold for us, but, up until now, the basic laws and principles of classical thermodynamics hold true, and they are compatible with statistical thermodynamics (i as much as I know of).--186.32.17.47 (talk) 15:57, 19 November 2012 (UTC) distinction between thermodynamics and statistical mechanicsThermodynamics and statistical mechanics are both important in physics. Their relation is worth looking at. PAR and editor 201.204.200.18 have very kindly written something about this above here. Count Iblis also has views on this. The difference between macroscopic variables and microscopic variables is worth looking at here. One is concerned with a body of matter. Microscopic variables usually refer to particles, such as atoms, molecules, electrons, and many others. Macroscopic variables do not refer to particles. They refer to quantities that can be measured by certain kinds of macroscopic apparatus in the laboratory. Thermodynamics is particularly concerned with macroscopic apparatus that allows control and knowledge of the mechanical and chemical states of a macroscopic body. The control is considered to be exerted from outside the body. The knowledge is considered to be entirely provided by the history of the external controls. The individual particles within the body are considered to be inaccessible, both as to knowledge and as to control. In contrast, statistical mechanics is built on assumptions of knowledge and on measurement of the adventures of the individual particles of the body, as well as on the concerns of thermodynamics.Chjoaygame (talk) 21:24, 16 November 2012 (UTC) In a small sample of some textbooks of thermodynamics I found that the following do not mention Boltzmann's constant:
I found three that had sections on what they called statistical mechanics or statistical thermodynamics, which just in those sections did mention Boltzmann's constant:
Addendum of text quotes for the benefit of DamorbelAdkins (1968/1983) writes on page 78 about what he calls the discipline of Statistical Mechanics or Statistical Thermodynamics, and refers the reader to Kittel & Kroemer (1980). Kittel & Kroemer (1980) is entitled Thermal Physics. It is a textbook of statistical mechanics or statistical thermodynamics, as indicated by Adkins. Kittel & Kroemer give references to books on thermodynamics, including Pippard, A.B. (1966), of which they say "Very careful discussion". Reif, F. (1965) is entitled Fundamentals of Statistical and Thermal Physics. It is a textbook of statistical mechanics, not a textbook of thermodynamics. Amongst other books that it recommends for what it calls macroscopic thermodynamics it lists on page 632 Guggenheim, E.A. (1960), and Pippard, A.B. (1957). These and many other authors explicitly distinguish statistical mechanics from thermodynamics. For example, Callen, H.B, (1960/1985), Thermodynamics and an Introduction to Thermostatistics, John Wiley & Sons, New York, writes on page 5: "Like all sciences, thermodynamics is a description of the results to be obtained in particular types of measurement." Adkins (1968/1983) writes on page xi: "Many books and courses on thermal physics attempt to develop classical thermodynamics and statistical mechanics side by side. Although it is essential that the relationship between the two be established at some stage of a scientfic undergraduate's education, it is best to teach classical thermodynamics first and separately, for the ability to use it well depends largely on knowing what it can achieve without appealing to the microscopic nature of things." Regardless of Adkins opinions about the best way to teach, this shows unequivocally that he distinguishes between thermodynamics and statistical mechanics. Statistical mechanics in Adkins (1968/1983) is confined to section 5.6 on pages 77–86. Pippard A.B. (1966) on page 1 writes of ..."classical thermodynamics, the subject of this book. Here the method of approach takes no account of the atomic constitution of matter,...".Chjoaygame (talk) 12:29, 19 November 2012 (UTC) response by Damorbel
further response by Damorbel
repsonse by editor 186.32.17.47I do not know what is the problem here. There _is_ a general theory of thermodynamic equilibrium: that is _true_ and it goes before and beyond statiscal mechanics, but it is _compatible_ with statistical mechanics. What is the problem? Of course stastiscal mechanics is an important aspect of thermodynamic knowledge. But the general laws and principles of thermodynamics as established by, i.e, Gibbs, do not require statistical mechanics for their formulation (in as much as the general theory of relativity is not about quantum mechanics but they should be compatible somehow). I do not know what the disagreement is about. An article on thermodynamics should encompass the general equilibrium theory, with it's four laws and diverse principles: the universe that we have, derived from the work of Gibbs, Carnot, Clasius, etc., that is used to predict conditions of equilibria and steady state situations and functions of state with work and heat as functions of path, and also the development of statistical mechanics and it's compatibility and enhancement of thermodynamics (which is, in itself a great accomplishment of science). What is wrong is to pretend that all reasoning in thermodynamics is based on statistical mechanics. And also to pretend that thermodynamics is about the study of "heat transfer" (explicitly or implicitly). The mechanism of "heat transfer" is not that important in thermodynamics, safe, conduction and it's relation with statistical thermodynamics and radiation similarly. Mixed methods of transfering heat that involve mass transfer along with heat transfer (convection and advection) depend a lot on the definition of the system and are better placed in an article on "heat transfer", as calculations of work and energy and momentum in mechanics are better placed there, but the compatibility of science (up until know there is compatibility: we do not have a theory of everything that links quantum mechanics and gravitation nor we comprehend much about dark matter and dark energy, etc.) should be pinpointed to certain detail.--186.32.17.47 (talk) 16:29, 19 November 2012 (UTC) |
- ^ Partington, J.R. (1949), p. 118.
- ^ Maxwell, J.C. (1871), p. 10.