Talk:Thermodynamics/Archive 2

Archive 1

Archive 2

Archive 3

Lord Ceder ???

someone appearently removed the picture from Carnot from this article and added instead a picture of Gerbrand Ceder, together with the statement that 'Many' would consider this person as the new lord of thermodynamic. The citation given is the research Pager of Dr. Ceder.

Although I cannot fully judge wether Dr. Ceder is worth mentioning at this position, i don't find any proof for the consideration as Lord of Thermodynamics in the citation. Mr Ceder would be the only person mentioned in the history of thermodynamics since 1849. —Preceding unsigned comment added by 194.94.232.86 (talk) 13:26, 6 December 2007 (UTC)

Unified thermodynamics

Unified thermodynamics is pure nonsence. So I have removed it! CaptinJohn (talk) 10:50, 7 December 2007 (UTC)

GA Sweeps (on hold)

This article has been reviewed as part of Wikipedia:WikiProject Good articles/Project quality task force in an effort to ensure all listed Good articles continue to meet the Good article criteria. In reviewing the article, I have found that the following issues need to be addressed.

• Much of the article is missing inline citations. I realise the information is readily available in any textbook, but that should may it easier to find citable sources. Main articles of summary-style sections can probably be mined for appropriate references quite easily.
• The laws of thermodynamics section should be cleaned up to match proper style for embedded lists. Despite being covered in detail in their own article, I'd suggest expanding the information on each law a little more as well.

 Fixed by using tabular format for emphasis of this important section (also felt a list with a lot of text was harder to read) and adding additional text from the individual articles to fill out the descriptions. David Hollman (Talk) 09:55, 31 August 2010 (UTC)

• The "Thermodynamic potentials" section needs improvement on jargon issues (for example, each of the variables in the equations needs explaining) and further wikilinking.

 Fixed, David Hollman (Talk) 10:17, 31 August 2010 (UTC)

• Is there a reason for using numbered lists in the "Thermodynamic systems" and "Processes" sections? If not, bulleted lists should be used instead.

 Fixed, numbered lists replaced. David Hollman (Talk) 09:55, 31 August 2010 (UTC)

• Minor grammar: the first sentence of the "Classical thermodynamics" section is a run-on; I wasn't sure how best to fix it.

 Fixed, David Hollman (Talk) 09:55, 31 August 2010 (UTC)

As long as work is being done towards fixing these issues, I see no reason to delist the article. Some other points/suggestions, unrelated to GA status:

• I find the lead moving image very distracting. I don't know if it's possible, but could it be changed to a startable-stopable movie?
• Is the a convenient way to expand the "Thermodynamic states" section? The summary style explanation given here seems a bit brief, but may well be complete as is.

Feel free to drop a message on my talk page if you have any questions, and many thanks for all the hard work that has gone into this article thus far! --jwanders^Talk 18:14, 28 February 2008 (UTC)

GA Sweeps: Delisted

Since the majority of the above issues were not addressed, the article has been delisted. Add additional citations from a variety of sources to provide a balanced representation of the information present. Perhaps sources can be pulled from the main articles linked to within the article. Look to books, magazines, newspaper articles, other websites, etc. The lead should also be expanded to better summarize the article, see WP:LEAD guidelines. Although the article has been delisted, the article can be return to GA status by addressing the above points. Once sources are added and cleanup is done, I recommend renominating the article at WP:GAN. If you disagree with this assessment, a community consensus can be reached at WP:GAR. If you need clarification or assistance with any of these issues, please contact me on my talk page and I'll do my best to help you out. --Happy editing! Nehrams2020 (talk • contrib) 00:35, 18 June 2009 (UTC)

Why wasn't this set up in a regular GA reassessment? It would've showed up on the Article Alerts and the physics project would've been aware that this article had issues. I suspect response hasn't been all that great (or at least not all that it could've been) for these GA sweeps. Next time you decide to do one, I would strongly recommended using the usual channels so bots can pick things up. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 04:19, 18 June 2009 (UTC)

Normally reviews go through a subpage, but it looks like the initial review was performed back in February 2008 (don't think that article alerts was set up back then), and I'm closing it now in the absence of the reviewer. When articles are placed on hold it is customary for reviewers to contact the main contributors and the related WikiProject(s). It appears that ample time was provided for the article to be improved, and now that it has been delisted, the issues can be addressed and the article renominated. --Happy editing! Nehrams2020 (talk • contrib) 06:30, 18 June 2009 (UTC)

Ah well that explains it. (I read 28 Feb 2009).Headbomb {^ταλκ_{κοντριβς} – WP Physics} 13:47, 18 June 2009 (UTC)

Untitled

Thermodynamics deals with the transformation of energy into work and heat. Work is what is equivalent to "lifting a mass" = opposing a field (gravitational, electromagnetic, nuclear...). Heat is what is rejected to the "universe" raising the universes temperature (energy rejected can't be used as "work"). Thus the concept of entropy (the "state function" of the universe that increases as energy is rejected as heat). There is no "heat energy" involved, heat is what is rejected to the universe as processes are carried out. The main confussion in the definition of Thermodynamics and mixup with Heat Transfer is when laymen confuse the etymology of the word thermodynamics with its current use in science and engineering. It's like confusing "atom" with something indivisible,as its greek roots suggest. —Preceding unsigned comment added by 65.182.27.96 (talk) 17:02, 7 April 2009 (UTC)

Please do not place comments above the talk page again. Every new post must be at the bottom; OK? --186.14.102.80 (talk) 21:59, 19 April 2009 (UTC)

I moved this down here to make it a little cleaner. Overthinkingly (talk) 01:55, 3 June 2009 (UTC)

statistical thermodynamics, a branch of statistical mechanics?

Not according to

http://en.wikipedia.org/wiki/Statistical_thermodynamics#cite_note-0

there it says: "The terms "Statistical mechanics" and "statistical thermodynamics" are used interchangeably. "Statistical physics" is a broader term which includes statistical mechanics, but is sometimes also used as a synonym for statistical mechanics". —Preceding unsigned comment added by Paranoidhuman (talk • contribs) 02:24, 12 August 2009 (UTC)

"Fourth Law" not general

I have removed the comment about the "Fourth Law" because it is very far from being as general as the three laws. Chjoaygame (talk) 03:29, 15 August 2009 (UTC)

The Second Law. In an isolated system Entropy increases. In an isolated system entropy is constant. People you can NOT have it both ways. This confusion is horrible.71.31.154.4 (talk) 04:55, 24 October 2009 (UTC)

The Second Law of Thermodynamics. Entropy of an isolated system increases. Entropy of an isolated system is constant. These two juxtaposed statements are direct contradictions. This confusion, as well as the failure to define the terms entropy and energy (as well as equilibrium) before using them in the Laws is surprising to say the least. I suggest an attempt to roughly explain them Energy is the ability to do work, Entropy is the measure of the disorder in a system, Equilibrium is the state of a system in which no work can be done and thermal equality is (macroscopically) obtained. Not to mention defining "Open", "Closed" and "Isolated" "systems". This is basic pedagogy. I am disappointed this is not up to minimal Wikipedia standards, IMHO 71.31.154.4 (talk) 05:09, 24 October 2009 (UTC)

Schools of thermodynamics

I would suggest that someone add an image and overview of the schools of thermodynamics:

• Schools of thermodynamics

The table of the twelve school founders gives a cogent overview of the subject of thermodynamics. If no one objects, maybe I'll add in a jpg of the school founders table. Feel free to leave comment. --Libb Thims (talk) 21:50, 22 July 2010 (UTC)

While some of the historical information might be useful, I would recommend against presenting it in that particular form. The men listed on the web page you mention are indeed influential, but the choice to present them each as a founder of a "school" is misleading, in that all those institutions existed before the individual arrived or anyone started studying thermodynamics there. As far as I can tell, the selection of that particular list of individuals, while it may have merit, is derived from author's personal opinion rather than any generally recognized list 12 founding schools or people. Bdentremont (talk) 01:51, 23 July 2010 (UTC)

As to your first point, you seem to be confusing the founding of a school verses founding of a school of thought, e.g. the University of Geneva was founded in 1559, whereas the Lausanne school, a school of teaching or thought physical economics, surrounding Leon Walras and his students at the University of Geneva, existed from about 1970 to 1910. This is what we are talking with each of the twenty known “schools of thermodynamics”. There is more than one textbook (or article) reference for each of the twenty articles connected to the above page, with full discussion found in the reference as to who each founder or leader of that school is. A few example quotes:

• Ilya Prigogine: “The Viennese school was led by Gustav Jaumann."
• Pierre Duhem: “The chiefs of the Dutch school are Van der Waals, Roozboom, and Van’t Hoff.”
• John Schmitz (2007): “The University of Berlin was the world’s leading institute for thermodynamics and is therefore also called the Berlin School of Thermodynamics [led by], Hermann Helmholtz, Rudolf Clausius, and Walter Nernst."
• Ralph Anderson (1999): “Ilya Prigogine is founder of the Brussels school”.
• Anon (1970): "István Gyarmati is founder of the modern Hungarian school of thermodynamics."

There's literally literally dozens of these types of references, indicating that these various schools are common inside jargon. In any event, the linked page has been (updated more today) give giving overview on the twenty-one (or more) known schools of thermodynamics, and the newly made "school connectivity diagram", showing their interrelations, is pictured here.

I would suggest that a picture of the table of twelve people representative of each school (along with the connectivity diagram), go in the article. If you have some sort of objection to any particular person not being the best representation of that school, please state your reasoning. Whatever the case, if no one wants this type of pictorial overview of how the subject of thermodynamics came to be, then I guess I will leave it be? Yet the one lone picture of Sadi Carnot in the present thermodynamics article hardly does justice. --Libb Thims (talk) 19:03, 23 July 2010 (UTC)

If you read the notes in the modern translation of Carnot's work you will find that of the four of five things he stated based on mathmatical derivations or whatever, only the calculation of thermodynamic driving force based on temperature diffferential between the heat source and the heat sink, which is the concept of thermodynamic efficiency, was correct.

I agree that Sadi Carnot doesn't represent all of thermodynamics and appreciate your contributions to broaden this section. While I understand that they are intended to be schools of thought, I still feel that the fact that the names coincide with intitutions which are also called "schools" would be somewhat confusing to someone not already at least vaguely familiar with the names of the people, the institutions, and the dates. Your assertion that the "various schools are common inside jargon" may in fact be a good incentive to omit them under Wikipedia:Make technical articles understandable which suggests that technical jargon be avoid if possible.

I also now notice that the figures and references that you have added to the article all are sourced from or refer to a website that you administer. While not strictly prohibited, it is definitely a concern under Wikipedia:No original research. If you could reference back you your own sources rather than your article on the topic, I think you could make much stronger case. Particularly, I think that the assertion that these constitute a set of "the main schools" may constitute your own conclusion, particularly considering that the list on the source page has expanded from 12 to 20 during the course of this discussion. If you have a good source, other than yourself, to suggest these schools as a set of "main schools" (and you are obviously far more likely to know where to find this than I) I would really like to see that in the article.

I mean these as suggestions on presentation, not an attack on your work, and am not making any edits or reversions to the article right now. Also note that JPG is not the preferred format for these figures (See Wikipedia:Image_use_policy#Format) and it would be preferable if you could upload PNG or SVG. Best regards -- Bdentremont (talk) 06:35, 26 July 2010 (UTC)

I understand your concerns regarding references, however, I used to contribute heavily to Wikipedia articles (creating about 180 new ones), adding in upwards of 50-60 references per article. I now do this externally and to avoid contributing to Wikipedia articles, except only bits here and there, in such a way that I only commit minimal energy to the edit, instead focusing energy on my own project and objectives in collecting knowledge.

As for your concerns about original research, these are the first twelve schools of thermodynamics formed, called “schools” according to references, listed in purely chronological order, not my personal list of favorites.

Regarding inside jargon, these school names are all common terms people find when reading about thermodynamics. To exemplify, a popular school of thermodynamics name used commomly in recent years is the "MaxEnt school" (MaxEnt school), headed by Edwin Jaynes (one of the 21 schools that I know of so far), a term found on both the Maximum entropy thermodynamics and the H-theorem articles. Small discrepancies do exist, however, in the naming and heads of these schools: e.g. some cite Theophile de Donder as being the founder of the Brussels school, whereas others cite Ilya Prigogine as being the founder; also some call it the “Brussels school”, whereas others call it the “Belgian school” (and other refer to it as the "Prigogine school"). The cited link connects to a main discussion page (with references), with in turn connects to more than twelve other dedicated pages (each giving multiple references and historical overview) as to who first began to refer to that school as a particular school of thermodynamics, its origin, naming issues, etc.

In any event, this is all the energy I can devote to this article at the moment and is the best (quick) way I know of to give the new-comer a oneshot overview picture of the history and framework of thermodynamics. Most people new to a subject tend to scan articles quickly, often reading photo captions over that of reading the whole article. I uploaded a new png version of the connectivity diagram (in the future I’ll make note of this). --Libb Thims (talk) 18:56, 26 July 2010 (UTC)

Images

This triple expansion or three stage steam engine is a typical thermodynamic system, consisting of input from a heat source (boiler) on the left and output to a heat sink (condenser, not chown). Work is extracted, in this case by a series of pistons. image at 24 Jul 2010)

I'm going to upload some new images to the article. Per the above comment that the animated combustion engine is "distracting" (I think that I was the one who originally added that image a few years back), I will replace it with the original diagram, made by Sadi Carnot, of the Carnot heat engine, with some color and labeling. I will also replace the one picture of Sadi Carnot (current) with the pictures of the twelve main school founders per the above discussion, along with the school tree diagram. If someone has a particular objection to a certain school representative, please discuss below. --Libb Thims (talk) 14:39, 24 July 2010 (UTC)

I really liked the (removed) animation as an image though I am forced to agree it would be a bit too much for the top of the article. The replacement seems more appropriate. I have a concern though that the image size is a bit large, and this is compounded by a very long caption. However I think the caption text is valuable, as it gices a grounding by relating to real examples of a thermodynamic applications. I think that having such a concrete example is a great way to draw a reader into what can be for some a conceptualy difficult subject. I wonder if it would be better to move the image to introduction, and move some of the caption text to the main body? Though, this would displace the navbox, which does seem to fit the introduction okay. David Hollman (Talk) 10:26, 31 August 2010 (UTC)

Burk's equation?

I removed the following text from the potentials section as I could find no reference for "Burk's equation":

As can be derived from the energy balance equation (or Burks' equation) on a thermodynamic system there exist energetic quantities called thermodynamic potentials ...

I wonder if this could be related to Bourke engine? David Hollman (Talk) 10:26, 31 August 2010 (UTC)

comment on Materialscientist's new edit

Dear Materialscientist, Your new edit is not good. It needs radical revision.

Probably you have not chosen the right place to put your edit; probably what you want to say should be said earlier in the article, in a more introductory place. Your comment about black holes is already made in the introduction, and does not need repeating in the section on the laws.

The section on the laws is not the place to talk about Einstein's predictions. It is not clear what you mean by saying that Einstein predicted spontaneous emission. Spontaneous thermal radiation was recognized by 1791. It is true that Einstein predicted stimulated emission. But stimulated emission is not explicitly dealt with by thermodynamics, which needs to regard it as a negative contribution to absorption and not as part of emission proper; Kirchhoff's law of equality of radiative emissivity and absorptivity works only when this view is taken.

As it stands, the introduction section of the article lacks focus on the key ideas of thermodynamics, and some of its wording is loose. It does not tell the reader what are macroscopic and microscopic variables for the purposes of thermodynamics: the link to macroscopic scale does not do the job. Chemical composition is a main factor in present day thermodynamics, but hardly seems to be mentioned in the article. But what you want to say in your edit needs those key ideas.

You write of "laws which do not depend on the details of the systems under study or how they interact". This is too vague. Thermodynamics is about changes in systems that can be described by macroscopic thermodynamic variables, but do not require knowledge of their microscopic variables.Chjoaygame (talk) 12:30, 4 March 2011 (UTC)

You are welcome to try revising the article, especially if your additions are combined with reliable references. I don't recall adding anything to this article myself - you might be confusing my vandalism reverts with additions. Materialscientist (talk) 12:39, 4 March 2011 (UTC)

Dear Materialscientist, Please accept my apology. I lost track of the multiple edits. Yes, now I think I see that you didn't add anything. My complaints should not have been addressed to you. They apply to the version that has been there for some time. I think they are valid complaints, but I haven't spent time trying to fix the article, because, as is only too obvious to you, it takes a lot of effort to make a little change, and this article isn't one that I watch very closely. I have other fish to fry.Chjoaygame (talk) 14:10, 4 March 2011 (UTC)

The diagram-table of kinds of system

Thermodynamics distinguishes adiabatically closed and diabatically closed systems. In a sense, it this distinction on which the whole of thermodynamics is built. It is desirable to include this distinction in the article. An adiabatically closed system can exchange work but not heat; a diabatically closed system can exchange heat but not work. The present text of the article simply refers to the diagram-table that distinguishes isolated, closed and open systems, but I do not know how to edit such a diagram. Please would the editor who knows how to do it let me know, or do it himself?Chjoaygame (talk) 02:12, 11 April 2011 (UTC)

You mean 'rigid' for 'diabatic', I believe. Assuming this, you point is well taken. They are more important than 'closed' and 'open'.

Credit

From the start of the article, it says that thermodynamics is a branch of physics and chemistry. . . . . no, clearly the thermodynamics is very important for chemistry, but the branch itself originated on physics and thus only belongs to physics. Application of thermodynamics on the field of chemistry is studied by Chemical thermodynamics and Thermochemistry. Otherwise, what these derivatives are for? I'm confused, you know.--Twicemost (talk) 05:29, 22 April 2008 (UTC)

very true, thermodynamics has its origins in physics and is just used in chemistry, the same as quantum mechanics is used in quantum chemistry. i doubt anyone would say that quantum mechanics is a branch of chemistry —Preceding unsigned comment added by 24.36.181.171 (talk) 01:23, 23 June 2008 (UTC)

I also agree that it just does not make sense to say that thermodynamics is a branch of chemistry. It would be misleading for the readers. Surely chemistry or chemists have contributed to it, but that does not change the fact that TD is one of the fundamental subfields of physics, just like electromagnetism, or quantum mechanics or classical mechanics. -Ur —Preceding unsigned comment added by 71.103.0.107 (talk) 09:53, 12 July 2008 (UTC)

There lies the rub, for What is "Chemistry", what is "Physics"? Where does one end and the other begin? I took Physical Chemistry, Organic Chemistry, ... I took 4 physics courses and many engineering courses and what I got from it is that the "point of view" of the physicist, the chemists and the engineers were quite different on the same subjects or phenomena. Thermodynamics is one of the most fundamental concepts for all of the physical sciences, it's laws are obeyed by the universe weather it is at a subatomic, atomic, "classical" or astrophysical level, all from concepts initially derived form a practical concern with combustion in order to produce work. Weather one does mechanics or electricity or astrophysics or nuclear physics or chemistry... one always ends up using the laws of thermodynamics to solve quite a lot of problems. —Preceding unsigned comment added by 190.241.6.32 (talk) 08:34, 5 April 2009 (UTC)

When thermodynamics began, there was no distinbction between physics, chemistry, biology, biochemistry, astrophysics,... It was called science then. So, the area does not 'belong' to either, but it is a fundamental part of chemistry and of physics (or "of physics and of chemistry"). The importance of gicing 'credit' to one or the othermay not be the most valuable use of time. —Preceding unsigned comment added by Hkerfoot (talk • contribs) 14:20, 22 April 2010 (UTC)

Now 'science' has been classified. Thermodynamics does not discuss the breaking of chemical bonds. It's a theory in physics, with applications to chemistry and innumerable natural sciences. 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) ('Geologist')

history

am not really sure about the history section written about ancient times. Those early ideas on void spaces and atomic philosophy have no real contribution aside from influencing future scientist, but the way its presented on this page makees it seem as those thermodynamics existed millenium ago, which of course is not true. I dont object to those points being there but i think there needs to be better effort to clear draw a distinction between the early ideas, which are not thermodynamics, and the actual science of thermodynamics.Tomasz Prochownik (talk) 07:26, 22 June 2008 (UTC)

Also you mentioned that Avicenna invented the first air thermometer, but thats not quiet the whole story. Ctesibius, Heron, and Philo were all aware of the elasticity of air and they knew that when heated it expanded and vice versa and they in fact built several mechanisms demonstrating this principle, particularly in Heron's Pneumatica. In reality Avic. would have had access and knowledge of these works so he in fact just used their theories and the devices they built to measure temperature and some sources claim in fact that they did built an air thermometer themselves http://www.enotes.com/history-fact-finder/science-invention/who-invented-thermometer. whether they built an air thermometer is in no doubt, its just that they most likely didnt use to measure temperature, but never the less their ideas and inventions are crucial Avic. just used what they made to gauge temp. difference. I thought id let you know so you alter to include those ideas, you know before i actually do it for you soooooo. Tomasz Prochownik (talk) 06:41, 26 June 2008 (UTC)

ya check when i posted that comment, and you haven't changed anything, both the sources you list under the air thermometer are brutally inappropriate, Briffault one having something along the lines, some say he used an air thermometer, and the other source witting one sentence on it. The problem being neither book is source is about the history of science. give me a source that explains his thermometer, how it worked, and how he built it. I like your little contribution of principle parameter, it would be pretty hard for it to be that since it could not tell the temperature, only relative temp., since temp. scales didn't exist at the time, also it would have been subject to barometric pressure. what compounds this even further, as stated before neither of your sources claim how it was built, how it worked, or anything to do about this device, except a sentence, i guess you thought you'd fill in the gaps huhhh. As far as measuring air temp. a rudimentary device was built by philo http://books.google.ca/books?hl=en&id=qfmS7g4JzjwC&dq=Principles+and+Methods+of+Temperature+Measurement&printsec=frontcover&source=web&ots=3rLkeqdZz5&sig=tV2YrszNevkr61Eatbrk0YDiB4A&sa=X&oi=book_result&resnum=1&ct=result. of course avic. had access to these works also. Last, but not least these early devices are not thermometers, but more accurately thermascope's. any comments

as far as your knew contribution, well once again filled with some distortions as usual. Heron also conducted experiments on voids, but of course his don't count right, because as you would have us believe muslims invented experiments, right lol, but that's soon going to be addressed. Ya conducted the first experiments on a void, really were does it say that in the Stanford source specifically, as far as the other source Zahoor thats just a plain joke, kind of like you. Last but not least, this contribution is absolutely worthless to the history of thermodynamics. Why, simple show me the connection between this and thermodynamics, list one source that links this as being important to thermodynamics. Ideas on voids were just ideas, based on Greek philosophy. all the early ref. on this page are just precursor ideas to thermo., ideas like voids or atomic philosophy, not thermo. itself. what makes this contribution even more worthless is the fact he conducted "experiment", and i use the word loosely not experiments, he used them to demonstrate something totally untrue, vaccum's can exist. Ahhh what a monumental contribution he used water plungers to prove the exact opposite of what is true. You've really outdone yourself here jagged lol. So pretty much this little bit is gone unless you can find some respectable source liking this to thermodynamics. I don't care about you interpretation, find me a respectable source that links this to thermodynamics, quote one for me please, am dying to know. Am now also making changes to the thermometer part as well, since you wont I and you better start looking for better sources on this device cause this ain't cutting it sorry.Tomasz Prochownik (talk) 07:02, 14 July 2008 (UTC)

Why no mention of Joseph Black and James Watt, who did the essential background work necessary to formulate thermodynamics?Phmoreno (talk) 01:07, 13 October 2010 (UTC)

The above comment by Phmoreno is a good one. Black's work was key. Also, thermodynamics was preceded by caloric theory, which continued to be used by many founders of thermodynamics because they knew it better and it was 'close enough' :-) 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) ('Geologist')

Etymology

I suggest the etymology given:- "Roughly, heat means "energy in transit" and dynamics relates to "movement"; thus, in essence thermodynamics studies the movement of energy and how energy instills movement" is really unsatisfactory for a work of reference. To say heat is "energy in transit" is obscure, to have the quality of heat a body has only to have a steady temperature above absolute zero, there is no need for the "energy to be in transit". Conversely, "dynamics" is used in many branches to convey the concept of movement, electrodynamics and electrostatics are good examples where "dynamic" is used to distinguish between moving and none moving charge. The analogy is compelling. To paraphrase Thermodynamics - "energy in transit" "movement" is prolix, using only one word for movement is much better style. By way of comparison, Thermodynamics "heat" and "movement" indicates very well the actual fact that thermodynamics is the science that converts heat energy to mechanical movement and viceversa, nothing "roughly" about this! --Damorbel (talk) 21:41, 6 July 2008 (UTC)

I think you may be confusing heat and thermal energy or internal energy. Heat is the transfer of energy, not the amount of energy something has due to its temperature. It is an important distinction in thermodynamics. PhySusie (talk) 10:44, 12 July 2008 (UTC)

'Energy in transit' is not necessarily heat. Mechanical or electrical work is usually not called heat. Bo Jacoby (talk) 09:47, 14 July 2008 (UTC).

Right - only the transfer of thermal energy. My point to previous post was that heat is not a quality that an object has. Thanks for catching that. PhySusie (talk) 13:56, 14 July 2008 (UTC)

Defining "Heat is the transfer of energy" seems to leave you with temperature hanging in the air. What, in your definition, is temperature? It certainly isn't a measure of thermal energy. Does your definition of heat mean that a system in thermal equilibrium "has no heat"?--Damorbel (talk) 07:21, 23 September 2008 (UTC)

Heat _is_not_ "the transfer of energy" heat is the energy rejected that was not transformed into work. Recheck the second law and first laws of thermodynamics. E=W+Q the energy is transformed into work rejecting heat, raising the entropy of the universe. In this case energy is all kinds of energy not "heat energy" energy is potential or it is kinetic, if it is potential it implies a "property" that interacts with a "field" and thus has potential energy if it is not in equilibrium. —Preceding unsigned comment added by 190.241.6.32 (talk) 08:40, 5 April 2009 (UTC)

My driving a nail produces more than heat. 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) ('Geologist')

You can read the detailed history of the etymology of the term "thermodynamics" here:

● Thermo-dynamics

--Libb Thims (talk) 20:14, 20 July 2010 (UTC)

The above link takes me to a reference. My understanding of the etymology is that the application of the mathematics in Legendre's 'Dynamics' caused some to think of adding heat to his work 'essentially' produced a 'Thermodynamics'. 209.218.108.23 (talk) 21:10, 22 September 2011 (UTC) (Geologist)

Rational thermodynamics

This section is in the wrong article, it contains a link to a non existent article (Rational Thermodynamics), it is submitted by [Petr10] an untraceable user. I suggest it has no place here; I propose to delete it shortly.

Further the archiving is far too aggressive; since they are so small can't they be restored. I am looking into it.--Damorbel (talk) 07:48, 18 March 2009 (UTC)

I've never heard of Rational Thermodynamics before. [Not meant to be a slight on thermodynamics. :) ] I tried looking for that term in the index and TOC of one of the references for that section at Amazon.com.[2] Couldn't find the term rational thermodynamics. :--Bob K31416 (talk) 14:22, 18 March 2009 (UTC)

I found something on it in the other reference. Don't delete without better reasons.

Excerpt from one of the references re Rational Thermodynamics

2.3.3. Rational thermodynamics (RT) Rational thermodynamics is another class of microscale thermodynamic approaches. Initially developed by Coleman [19], Eringen [31], Noll [64], Truesdell [72], this approach has proven to be a useful component of methods for deriving constitutive equations [51]. The method is mathematically rigorous and is built on principles that lead to certain mathematical forms for the energy and constitutive functions [31]. Although the principles have some mathematical appeal, Maugin [59] has pointed out that they are actually only working hypotheses while Vavruch [73] claims they are more accurately called useful rules. These rules include the following: • equipresence—if an independent variable is present in one of the constitutive equations, it will, a priori, be present in all; and • memory—present effects are dictated by the past as well as the present values of the independent variables. Operationally, equipresence dictates that each dependent variable will be a function of all of the system �s independent variables, except when the presence of the variable contradicts some law of physics or material symmetry. It leads to a postulated form of functional dependence of internal energy that is far more complex than the ET form and seemingly unrelated. Memory further requires that the dependent variables be functions of both past and present values of the independent variables. 168 W.G. Gray, C.T. Miller / Advances in Water Resources 28 (2005) 161–180 In the case of flow in porous media, these two hypotheses impose some generality that is seemingly needlessly complicated. A somewhat simplified approximation that relieves some of the mathematical tedium has been put forth [48]. Maugin [59] also states that RT assumes notions that are precisely defined in ET to exist in any dynamic state. In RT, absolute temperature and entropy are considered primitive concepts and are believed to hold far from equilibrium; but they have no precise physical interpretation or physical relation to their ET counterparts. Materials are allowed to have a memory, and the concept of local equilibrium is not necessarily enforced. RT is the thermodynamic approach most widely used in considering macroscale porous medium systems [14,37,46]. The problem of lack of correspondence between microscale entropy and temperature between ET and RT is compounded when the RT hypotheses are made at the macroscale such that this approach can be physically unsatisfying. For example, the use of derivatives of energy with respect to saturation as the definition of capillary pressure e.g. as reviewed in [47] and the appearance of three different mathematical definitions of pressure [14] are indications that the mathematical elegance of the RT approach is achieved while sacrificing the ability to relate easily terms appearing in derived conservation and constitutive equations to experimental measurements and observations.

--Bob K31416 (talk) 17:22, 18 March 2009 (UTC)

I did some more looking and googled "rational thermodynamics" (including parentheses) and got 1260 hits. --Bob K31416 (talk) 19:22, 18 March 2009 (UTC)

But (LOL) there does seem to be a problem. The section doesn't seem to say anything. It doesn't look ready for prime time so I moved it to this discussion page.

Rational Thermodynamics moved from article page

== Rational thermodynamics ==

Main article: Rational thermodynamics

The classical methods of equilibrium and nonequilibrium thermodynamics do not allow for a description of states and processes outside equilibrium. The methods of rational thermodynamics eliminate the difficulties of the previous theories. Rational thermodynamics is a purely phenomenological and macroscopic theory disregarding molecular structure and its ultimate objective is to describe the actual physical phenomena in course of time and space as faithfully as possible. For example, the behaviour of continuous systems subject to mechanical and thermal solicitations. It is true that statistical thermodynamics offers a deeper insight, but it cannot in principle replace the phenomenological description, because the results of a statistical theory are always interpreted in terms of a phenomenological theory. Rational thermodynamics can be regarded as a true thermodynamic image of actual physical phenomena.

Rational thermodynamics is formulated as a theory of continuous systems and it is a mathematical theory established by mathematicians and physicists such as Clifford Truesdell. Its exact form described by Miroslav Šilhavý is based almost exclusively on mathematical arguments and is accessible only for chemists with a very good background in modern mathematics. However, rational thermodynamics can also be presented in a simplified form in which the physical aspect of the theory is emphasized and the mathematical technicalities are omitted. In such an approach, the theory is demonstrated on comparatively simple models and on examples based on plausible physical and mathematical assumptions. This version of rational thermodynamics is aimed at non-mathematicians, chemists, physicists and engineers studying especially equilibrium, mixtures, transport phenomena and chemical kinetics.

--Bob K31416 (talk) 19:28, 18 March 2009 (UTC)

Petr10 should not be untraceable. My e-mail address is now registered on Wikipedia. I don't know how to make it 'traceable'.

Yes, I am new in Wikipedia and I am surprised by the hysterical tone of the reactions to my addition to Wikipedia. Is it always like this in Wikipedia? Calm down, people!

This is not a joke, it's a serious scientific matter. That somebody has not heard of rational thermodynamics does not mean that it does not exist. Anyway, the text taken from one of the references and included in one of the comments proves that it exists. If it exists, it should be in Wikipedia. If it is not there, it must be added.

Only one reaction has a merit: yes, the main article is not there. It will be there shortly. It has 34 references so it takes time to write it Wikipedia-way.

I will restore my addition when I am finished with the main article.

Bob, have you been appointed to be the final arbiter who can decide if it is 'prime time'??

--Petr10 18 March 2009

Petr10, Please define Rational Thermodynamics. Thank you. --Bob K31416 (talk) 22:47, 18 March 2009 (UTC)

Also - looking at the posts here - I don't see any hysteria or reason to be defensive. The editors who have posted here seem to be calmly looking into this section and trying to determine its merit. I appreciate the fact that they are investigating this in a professional manner. PhySusie (talk) 00:44, 19 March 2009 (UTC)

Bob, a shortened quote from 'Thermodynamics: A Dynamical Systems Approach' by Wassim M. Haddad, Vijay Sekhar Chellaboina, & Sergey G. Nersesov, Princeton University Press, 2005:

In the last half of the twentieth century, thermodynamics was reformulated as a global nonlinear field theory with the ultimate objective to determine the independent field variables. This aspect of thermodynamics became known as rational thermodynamics. As a result of this approach, modern continuum thermodynamics was developed using theories from elastic materials, viscous materials, and materials with memory. The main difference between classical thermodynamics and rational thermodynamics can be traced back to the fact that in rational thermodynamics the second law is not interpreted as a restriction on the transformations a system can undergo, but rather as a restriction on the system's constitutive equations.

Another edited quote from Internet:

RT is mathematically rigorous yet physically well founded theory for irreversible thermodynamics. It diverges from the classical theory to assume temperature and entropy to be primitive variables, not dependent on something else (like mass, length etc.). This enables it to postulate the existence of these quantities in situations far from equilibrium.

--Petr10 19 March 2009

Re "In the last half of the twentieth century, thermodynamics was reformulated as a global nonlinear field theory with the ultimate objective to determine the independent field variables. This aspect of thermodynamics became known as rational thermodynamics."

Could you explain what this means? Thanks. --Bob K31416 (talk) 05:34, 20 March 2009 (UTC)

Assertions such as The classical methods of equilibrium and nonequilibrium thermodynamics do not allow for a description of states and processes outside equilibrium. indicate a profound misunderstanding (to put it kindly) of classical thermodynamics. Equilibrium (in terms of "classical thermodynamics" is a condition where no energy is flowing (being transported). When energy is introduced into a system by definition energy flow is initiated, equilibrium no longer applies. Now it doesn't matter if you are firing up a steam locomotive, pulling the pin from a hand grenade or forcing a fluid through a porous membrane (typical non-equilibrium conditions), thermodynamics as based on the works of Boltzmann et al, explains matters quite well.

Petr10, do you agree? Do you have observations where it is clear that it is failure of classical thermodynamics and not a failure in the observer? Perhaps you could start show just how the second law of thermodynamics is "rather as a restriction on the system's constitutive equations". This would be helpful because the 2nd law has at its root the concept that you don't get energy from nothing.--Damorbel (talk) 08:34, 20 March 2009 (UTC)

I am terribly sorry to disappoint you but I cannot argue with you and I cannot explain anything myself. I just want to show on Wikipedia an article that explains the situation with rational thermodynamics. That's all. RT has friends and enemies, see the discussion from which I took my earlier quote in Journal Club Theme of October 2007: Irreversible thermodynamics of continuous media - in that discussion, Kosta Volokh does not like RT.

The article that I want to show has not been published due to the death of the author who also wrote more general articles about thermodynamics, e.g. CONCEPTUAL PROBLEMS OF MODERN IRREVERSIBLE THERMODYNAMICS.

--Petr10 (talk) 17:40, 20 March 2009 (UTC)

Petr10, you say "I cannot explain anything myself" which makes one wonder why you want to edit here. The idea of an encyclopedia is to have a reasonably reliable store of knowledge available for consultation. Wikipedia is a very attractive proposition for people who wish to publicise their own point of view, since Thermodynamics is a rather obscure subject there are many want to post here. Bearing this in mind would you mind putting your contributions in a separate article? If you cannot show the link between Rational thermodynamics and classical thermodynamics, then Rational thermodynamics has no place in this article.--Damorbel (talk) 19:59, 20 March 2009 (UTC)

Exactly! A "reliable store of knowledge available for consultation" is what I want. I want to contribute to that. That's one reason why I am doing it. (But it's more like an obstacle course.) Putting my "contributions in a separate article" is what I want (I mentioned it earlier). It will certainly be reliable!

You and I cannot understand everything! To be able to explain RT to you, I would have to study a lot of things and you would have to study a lot of things otherwise you would not understand it anyway even if I am able to explain it to you. People who have the right background and are really interested will benefit from my contribution.

"If you cannot show the link between Rational thermodynamics and classical thermodynamics, then Rational thermodynamics has no place in this article" is worrying. Of course there is a strong link but not necessarily the easy way for everybody to understand.

Your article is called 'Thermodynamics'. It is not called 'Classical thermodynamics' and it is not called 'Thermodynamics in 19th century'. That's why a link to my article (not necessarily the text that I put in originally) must be in 'Thermodynamics'.

A lot is happening and if you decide to ignore it because you personally cannot understand it, you are hurting Wikipedia. There are many people in the world who can understand it. Some of these people will be able to improve my article or extend it. --Petr10 (talk) 00:52, 22 March 2009 (UTC)

How did you come to be interested in Rational Thermodynamics? --Bob K31416 (talk) 22:50, 25 March 2009 (UTC)

Bob, I came across my cousin's unpublished (because of his death, otherwise he published a lot) article about RT, discovered that RT has not yet been mentioned in Wiki. (although the book 'Rational Thermodynamics' is in under Clifford Truesdell), and decided to put it in as the 'main article'.

However, you were right, my text (culled from the article) was not 'prime time'. I will try to get something better.

I think this discussion can now be closed. --Petr10 (talk) 17:37, 27 March 2009 (UTC)

Good luck and best regards, --Bob K31416 (talk) 18:26, 27 March 2009 (UTC)

Just an addendum: 'Rational Thermodynamics' has been around for decades. I've a dozen old photocopies of articles from the one journal that published the articles, which requires significant applied mathematical knowledge to read. Petr10's first, long definition was my understanding of it's general gist. However, it also tries to place classical thermodynamics on a rational foundation: some of these problems are discussed in English in the books by Bridgman. The papers are all axiomatic. 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) (Geologist)

Lay translation for the masses

I'm considering putting in an addendum at the bottom of the article to give some meaning to the equations found on this article. Many people come to this source to understand the material better as well as learn the history of the subject being related. There are a lot of significant points, but the lay person is going to get lost without having some bases of "Delta H". Some general ideas or suggestions if this is going to significantly contribute or take away from the material before I begin trying to figure out how to translate this into commonese? --TLedbetter (talk) 18:42, 2 April 2010 (UTC)TLedbetter

Good idea to add translations. On a related point, the article contains unattributed statements including purported quotations without sources. I have replaced one example with referenced quotes. While WP allows math to stand on its own, WP:RS may require references for translations.TVC 15 (talk) 21:10, 5 April 2010 (UTC)

Adding a section of practical intrepretations and applications may be useful. This could include a table of theoretical and parctical efficiencies of the commonly used cycles like Rankine, Diesel and Otto. Phmoreno (talk) 14:34, 14 December 2010 (UTC)

The practical section I mentioned above would be a good place to discuss collecting energy from diffuse, low density sources like wind and solar.Phmoreno (talk) 01:33, 17 December 2010 (UTC)

Phmoreno's last suggestion is a good one. WRT fundamental quantities, delta H is the characteristic function on the chemist's laboratory bench; and it is listed as once of the few basic quantities actually measured by the chemist Denbigh (by means of temperature change, for it is just heat in the lab).

Energy is so abstract I don't understand it easily, after 50 years of daily study. It's easy to differentiate it and create all characteristic functions, but I should build thermodynamics from measurable quantities upward rather than energy downward. 209.218.108.23 (talk) 21:15, 22 September 2011 (UTC) (Geologist)

Unscientific Language

Phrases like "virtual afterthough" really don't belong here. What is it meant to mean? 194.72.120.131 (talk) 09:19, 8 July 2010

There are others as well. 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) (Geologist)

Formula's for the Laws of Thermodynamics?

Would it be instructive to reader's of this article if in the "Laws of thermodynamics" section there were some mathematical representations as well as text? It seems to me that the blocks of text are a little bit overwhelming. I will add some of this soon. Neutiquam (talk) 08:00, 14 December 2010

How many laws are truly fundamental, necessary, & sufficient? 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) (Geologist)

Entropy and life

In a recent edit by Chjoaygame it states - "The evidence we have so far is that life has evolved apparently from non-life, and this is is contradictory to a belief in a universal tendency to heat death". This is not true. The evolution of life on Earth does not result in a net decrease in entropy. The decrease in entropy due to life forms is more than compensated for by accompanying increase in the surroundings. PAR (talk) 09:46, 27 March 2011 (UTC)

Dear PAR, thank you for this. Individuals live and die. No need to appeal to increase of entropy in the surroundings. Cycles appear and disappear. Thermodynamics works because one chooses one's system and surroundings carefully, to have suitable separations in time and space scales, not because of a universal tendency to heat death. Choose an unsuitable system and surroundings, and thermodynamics won't work for it.Chjoaygame (talk) 11:04, 27 March 2011 (UTC)

Sure, I agree. I just wanted to make sure that it wasn't being implied that life is some sort of entropy-defying phenomenon. PAR (talk) 16:07, 27 March 2011 (UTC)

That's completely wrong. Thermodynamics works for any choice of system and surroundings. Dauto (talk) 19:59, 27 March 2011 (UTC)

What is wrong? PAR (talk) 23:53, 27 March 2011 (UTC)

Dear Dauto, thank you for this. It depends what kind of thermodynamics one means. Thermodynamics as understood by present day scientists is not all powerful, that is to say, it does not work for any choice of system and surroundings. Potentially, in the future, it might turn out that thermodynamics will be of wider applicability. The usual versions of thermodynamics, for example, suppose that the system contains so many molecules that surface effects do not matter; you can check this in any reasonable beginning textbook. What one might call 'quasi-static thermodynamics' supposes that the local entropy density is a function of the usual local state variables, and that the global entropy can be found by assuming that the local entropy density can be integrated over volume as if it were an extensive variable like mass. The comments that I just deleted were about predicting the cosmological future of the entire universe, saying that such prediction is a grandiose program, and that carrying it out would require information not currently known, and in particular that it would require something like a calculation of the entropy of the entire universe, a calculation that lies more in the realm of grandiose fantasy than within the scope of feasible classical thermodyanamics. I made a mistake in raising this topic here and that is why I deleted the comment; I do not think further discussion of this matter is likely to be useful here and now.Chjoaygame (talk) 02:18, 28 March 2011 (UTC)

All you said is true, and yet thermodynamics works in the sense that all its laws apply. Dauto (talk) 03:12, 28 March 2011 (UTC)

Apply to what? If you mean all its laws apply to those systems for which its laws apply, then that is a statment without content. The second law does not apply to an electron. PAR (talk) 04:49, 28 March 2011 (UTC)

Strictly, classical equilibrium has proved itself very useful for system and environment in equilibrium (and close to equilibrium systems). One must extrapolate elsewhere, with unpredictable results. How can we test the two laws far from equilibrium? What is the basis in our religious belief that they apply? All theories have domains of application. 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) (Geologist)

Experimentally Reproducible?

The second paragraph of this article troubles me for several reasons. At very least it needs to be more clear. Here are my concerns:

1. "Thermodynamics concerns phenomena that are experimentally reproducible." While this is a true statement, it can also be applied to any other branch of science. I am not sure why it is here, and the rest of the paragraph does little to answer the question.

2. "For example, a state of thermodynamic equilibrium is a steady state reached after a system has aged so that it no longer changes with the passage of time." Again, this is technically true, but very confusing. It is not the age of the system that is important, but the equilibrium. Equilibrium is mentioned in the next sentence, but again, not clearly. My understanding of equilibrium is not that it does not change, but that any change is countered by an equal but opposite change, statistically speaking. E.g. when a body of water in a closed system (at STP), some water molecules are always evaporating, but other molecules are condensing at an equivalent rate; thus the proportions of liquid and gaseous water remain constant. If the system is assembled in equilibrium proportions, no "aging" is necessary. I believe the same is true of heat transfer.

3. The third sentence is nearly unintelligible. I think it means that the equilibrium conditions are somehow dependent on initial conditions. I'm not sure that this is quite right.

4. The fourth sentence returns to reproducibility. As I pointed out earlier, this term is usually associated with a concept at the core of the philosophy of science. I think the author meant to use a different term that refers to the return to equilibrium.

5. "This [reproducibility] is the source of the strengths and the weaknesses of thermodynamics. Thermodynamics does not deal with phenomena that are not experimentally reproducible." These two sentences do little to clarify what comes before. We might suppose that thermodynamics is limited to equilibrium systems, but I'm not sure 'weakness' is the right word to use here. The last sentence is completely useless. No science deals with phenomena that are not reproducible to at least some degree (the historical sciences -- paleontology, archeology -- are a dubious exception), so this trait cannot make thermo any "stronger" or "weaker" than any other science. besides, these terms are value judgments and thus probably inappropriate in this context.

Overall, this paragraph is unclear and possibly misguided. Perhaps the author was striking at a deep idea, but it hasn't come across, and it does not function well to introduce the topic of thermo. In that case, it belongs in a later section.

I suspect that this whole paragraph can be replaced with something like, "Thermodynamics deals with predictions of the equilibrium states of a system. It does not predict the manner in which the system changes toward equilibrium. Equilibrium is the state of a system in which, absent any external forces or external energy transfers, a change in the system is countered by an equal but opposite change, so that the system appears to be static." --Cladist (talk) 11:54, 26 April 2011 (UTC)

I agree with your criticism and suggest that you go ahead and make a revision. Perhaps some others will join in and help.Phmoreno (talk) 14:23, 26 April 2011 (UTC)

Dear Cladist, thank you for your commentary. May I reply? Dear Phmoreno, you agree with Cladist so my reply to Cladist may be addressed to you also.

Many inferences are drawn from the apparently entirely general nature of thermodynamics, but it is necessary to be clear about just how far that generality extends. The unwary novice needs to be warned of this right from the start.

1. "Thermodynamics concerns phenomena that are experimentally reproducible." While this is a true statement, it can also be applied to any other branch of science. I am not sure why it is here, and the rest of the paragraph does little to answer the question.

Many branches of science are concerned with phenomena that are not experimentally reproducible. For example, the earth, so far as is currently known, has no identically prepared copy (identicality here meaning identicality as defined in thermodynamic terms), and many aspects of its evolution are not experimentally reproducible. We have no strong reason to know that if the earth were prepared in an originally identical copy, all aspects of its evolution would be the same as those that have actually occurred. That is the meaning of the theory of evolution, that the specific evolution of species occurred through unpredictable or chance processes; this is usually considered to be a scientific subject. Thermodynamics does not attempt to provide specific predictions of the evolution of species. The diverse evolutions of particular individual galaxies are evidently very variable, and so astronomy is also a branch of science that deals with phenomena that are in some respects not experimentally reproducible. But some of the phenomena of astronomy are reproduced in nature, and they are the concern of thermodynamics. If you wish to be very particular about whether astronomy is an 'experimental' science, you can say that a typical astronomical experiment is to turn a telescope in a particular direction at a particular time and take a photograph with it. The turning of the telescope is the way of preparation. The content of the photograph is a record of the result of the experiment.

That the rest of the paragraph does little to answer the question you raise is a consequence of the short compass of the lead. But the general point still needs to be made at the start. The lead does not attempt to answer the question of how and why heat and work are distinguished, but it still needs to make the point that thermodynamics is about the distinction between them. In fact, the article does not do a good job explaining how and why they are distinct, and this needs remedy, but probably not in the lead. The lead raises issues, but does not usually settle them.

The reason why you are unsure about why this paragraph is here is that you presuppose that all branches of science deal only with reproducible phenomena. Perhaps you might like to reconsider that presupposition.

2. "For example, a state of thermodynamic equilibrium is a steady state reached after a system has aged so that it no longer changes with the passage of time." Again, this is technically true, but very confusing. It is not the age of the system that is important, but the equilibrium. Equilibrium is mentioned in the next sentence, but again, not clearly. My understanding of equilibrium is not that it does not change, but that any change is countered by an equal but opposite change, statistically speaking. E.g. when a body of water in a closed system (at STP), some water molecules are always evaporating, but other molecules are condensing at an equivalent rate; thus the proportions of liquid and gaseous water remain constant. If the system is assembled in equilibrium proportions, no "aging" is necessary. I believe the same is true of heat transfer.

Many texts speak of the aging of a system as a way of its reaching equilibrium. We agree that the statement is technically true. But you are concerned that it puts a wrong emphasis on age rather than on equilibrium. The next sentence agrees with your concern that it is not just age that matters; it intends to put the focus on what really matters, that, for a system defined by its way of preparation, the equilibrium reached must be the same every time. This is one of the fundamental presuppositions of thermodynamics, though perhaps it is taken by experts to be so obvious as not to need stating. But this article is for a wider audience, and they may not have that presupposition, essential though it is for thermodynamics.

You now express concern about the third sentence, which reads: "But more than that, for thermodynamics, a system, defined by its being prepared in a certain way must, on every particular occasion of preparation, upon aging, reach one and the same eventual state of thermodynamic equilibrium, entirely determined by the way of preparation." You find this third sentence unclear. If it continues to be unclear, then it will need to be re-written to make it clear.

You now tell us about your understanding of equilibrium: "My understanding of equilibrium is not that it does not change, but that any change is countered by an equal but opposite change, statistically speaking. E.g. when a body of water in a closed system (at STP), some water molecules are always evaporating, but other molecules are condensing at an equivalent rate; thus the proportions of liquid and gaseous water remain constant. If the system is assembled in equilibrium proportions, no "aging" is necessary. I believe the same is true of heat transfer." You are here telling us not about thermodynamics in general, but about the statistical thermodynamical explanation of macroscopic thermodynamics. But you are not telling us any reason why you think that the sentence about which you are concerned is wrong.

3. The third sentence is nearly unintelligible. I think it means that the equilibrium conditions are somehow dependent on initial conditions. I'm not sure that this is quite right.

You say that you find this sentence nearly unintelligible. You think it means that the equilibrium conditions are somehow dependent on initial conditions. You are not sure that this is quite right. Surely if a system is "defined by its being prepared in a certain way", then, in general, the eventual equilibrium that it reaches must depend on the way of its preparation? You write of "initial conditions" but the sentence is not framed in such terms: it is about the way of preparation. You are reading into the sentence a presupposition of your own, so that for you the sentence does not mean what it says. You are reading into it the presupposition that in some respects the system is prepared in a single definite way, but in other respects it is prepared in various ways, which you presuppose as various "initial conditions" applied to the aforesaid single definite way, "initial conditions" that may or may not affect the eventual equilibrium reached. For this reading, the sentence means that the single definite way affects the eventual equilibrium state, though perhaps the various "initial conditions" might not.

4. The fourth sentence returns to reproducibility. As I pointed out earlier, this term is usually associated with a concept at the core of the philosophy of science. I think the author meant to use a different term that refers to the return to equilibrium.

You think that reproducibility is usually associated with a concept at the core of the philosophy of science. Do you really mean to exclude unpredictable fluctuations from the purview of science? The fourth sentence reads: "The meanings of the terms used in this statement are clarified in the following, but experimental reproducibility is a primary and fundamental requirement for thermodynamics." It is not clear what you mean by "return to equilibrium" or why you mention it here.

5. "This [reproducibility] is the source of the strengths and the weaknesses of thermodynamics. Thermodynamics does not deal with phenomena that are not experimentally reproducible." These two sentences do little to clarify what comes before. We might suppose that thermodynamics is limited to equilibrium systems, but I'm not sure 'weakness' is the right word to use here. The last sentence is completely useless. No science deals with phenomena that are not reproducible to at least some degree (the historical sciences -- paleontology, archeology -- are a dubious exception), so this trait cannot make thermo any "stronger" or "weaker" than any other science. besides, these terms are value judgments and thus probably inappropriate in this context.

You write that "we might suppose that thermodynamics is limited to equilibrium systems". Some might suppose that, but not all. You write that you are not sure that 'weakness' is the right word to use here. Thermodynamics is not good at dealing with non-equilibrium systems, especially those far from thermodynamic equilibrium. Surely this is a weakness? The difficulty is that, in general, the evolution of physical systems is not necessarily experimentally reproducible; non-equilibrium thermodynamics is concerned with recognizing the cases of experimentally reproducible evolution of physical systems. People are trying hard to do something about this weakness. Are they wasting their time, do you think? Thermodynamics is good at dealing with equilibrium systems. Surely this is a strength? You write that the last sentence is completely useless, and that no science deals with phenomena that are not reproducible to as least some degree with the possible exception of "the historical sciences". Radio-carbon dating is an example. Insofar as it is true that there is some element of reproducibility in "the historical sciences", just so far and no further are they a concern of thermodynamics. You write: "besides, these terms are value judgments and thus probably inappropriate in this context". Is it really inappropriate to point out that a subject is successful in some of its aims but not yet in others? Why?

Overall, this paragraph is unclear and possibly misguided. Perhaps the author was striking at a deep idea, but it hasn't come across, and it does not function well to introduce the topic of thermo. In that case, it belongs in a later section.

You find this paragraph unclear and possibly misguided. You suggest that perhaps the author was striking at a deep idea, but you say that it hasn't come across, and that it does not function well to introduce the topic of thermo. You think that if it does not function well in the lead, it belongs in a later section.

Why do you say that this paragraph is "possibly misguided"?

The reason that you find the paragraph unclear is that it presupposes something that you disagree with, and that consequently is not in your way of thinking. It presupposes that some sciences deal with phenomena that are not experimentally reproducible. But it says that thermodynamics is not one of them. While you agree that thermodynamics is not a science that deals with phenomena that are not experimentally reproducible, apparently you seem to presuppose that no such sciences exist. Perhaps you might like to reconsider that presupposition.

The key to the idea of entropy is that it refers to experimental reproducibility. Entropy is one of the key ideas of thermodynamics, perhaps the main key idea. Without entropy and heat, one is dealing not with thermodynamics, but with energetics. Entropy cannot be easily discussed in the lead, but experimental reproducibility is, as you rightly say, an important notion in science, and is widely recognized to be so, and it is important for thermodynamics because entropy is important for thermodynamics. This is so important that it deserves a place in the lead.Chjoaygame (talk) 15:26, 26 April 2011 (UTC)

Rather than give a detailed answer to each point, I just want to say that I agree with Chjoaygame that equilibrium in thermodynamics is characterized by lack of change. The idea that this lack of change is "apparent" since there is a balance in two competing changes on the microscopic level is not classical thermodynamics, it is statistical mechanics, an explanation of the lack of change in classical thermodynamics. I disagree with Chjoaygame that science need not be about repeatable experiments. Experimental repeatability is absolutely fundamental to all science. Just because we have no duplicate of Earth does not mean we can form no scientific theory of the Earth. Carbon-14 dating of a rock is a repeatable experiment which tells the age of that rock, and inferences can be drawn about the age of the Earth from that. If we can divide a system into smaller subsystems which we can then perform repeatable experiments upon, then we are doing science. PAR (talk) 15:58, 26 April 2011 (UTC)

Why can't we reword some of this, such as: "Thermodynamic equilibrium implies that the driving force, such as temperature or concentraion difference or chemical reaction potential, that originally existed, has become exhausted." Also, examples of reproducible experiments should be cited, such as steam tables, enthalpy data, chet capacity data, etc.

Replying to PAR, Dear Par, thank you for this. It seems we agree that experimental reproducibility is fundamental to thermodynamics. That is what the paragraph asserts. More precisely the paragraph writes of experimentally reproducible phenomena. Though you write of "repeatable experiments", for your remarks to be quite relevant here, they will have to be read as meaning that you think that all science is about experimentally reproducible phenomena. The relevance of this would be that if it were true, it would be sufficient to say that thermodynamics was a science, without the need to explicitly emphasise its concern with reproducibility of phenomena. It is true that we can form a scientific theory of the Earth; but this is not to say that a duplicately (in the sense of thermodynamic duplication) prepared earth would lead to the same evolutionary outcome that we have found in the present earth. Non-equilibrium thermodynamics is about phenomena that are experimentally reproducible in the sense that thermodynamically duplicately prepared systems evolve to reproducible eventual states. In studying the scientific facts about the earth, we are interested also in the phenomena that are not experimentally reproducible. For example, we are concerned to sustain biodiversity by care of the environment because we think that we could not experimentally reproduce the evolution of species that might be destroyed by environmental destruction. It is perfectly scientific to think so. Therefore I ask you to reconsider your apparent view that all science is about experimentally reproducible phenomena.Chjoaygame (talk) 18:53, 26 April 2011 (UTC)

There is hard and soft science. The less a scientific discipline is able to organize its knowledge mathematically in terms of repeatable experiments and basic principles, the "softer" it is, and the less certain we are about its conclusions. The idea that we cannot reproduce the evolution of species is very soft science, it is not something you can prove mathematically from basic principles, so I would dispute the statement that it is perfectly scientific to think so. Thermodynamics is "hard" science, and I see no problem in making that clear in this article. PAR (talk) 21:09, 26 April 2011 (UTC)

Dear PAR, thank you for this. I am glad that we seem to agree that thermodynamics is a "hard" science, and that it is ok to say so. I think you are perahps rather strong on the idea of mathematical proof from basic principles. Perhaps you would say that anatomy was a "soft" science. But I am reasonably confident that the knee bone is connected to the thigh bone, and I don't have any problem about seeing that as scientifically valid. It was reliably known long before what I think you would accept as "basic principles", for example, perhaps, Newton's laws of motion?Chjoaygame (talk) 21:56, 26 April 2011 (UTC)

Replying to the unsigned comment by Phmoreno, Dear Phmoreno, thank you for this. The re-wording you suggest does not convey the essence of the message here, that PAR agrees with, but perhaps thinks not worth saying, and that Cladist accepts as true, but thinks so obvious that it is not worth saying, that thermodynamics is about experimentally reproducible phenomena and not about phenomena that are not experimentally reproducible. You are asking for examples of reproducible experiments, but this is a lead, not a detailed section of the article.Chjoaygame (talk) 18:53, 26 April 2011 (UTC)

I wish to make just a few remarks. If you qualify thermodynamics as being experimentally reproducible, you imply that at least one other scientific theory isn't. This is false. Also, I wish to correct a common error defining 'equilibrium'. Your static condition is part of a sufficient definition (that can't be expressed in an operational manner). Systems that equilibrate system and environment 'more rapidly' than the environment is changing are in equilibrium. I can't phrase this well; but it's in Enrico Fermi's slim volume (lecture notes), 'Thermodynamics'. Geologist have good results with equilibrium thermodynamics, even with magmas that are erupting. Also, I dislike 'driving force', for it implies the value of the characteristic function at equilibrium is somehow known by the system in advance. I also dislike 'reproducible', for it suggests to novices that the path is reversed, not the states. Duhem, Bridgman, and others have suggested other terms, but none are good. Better to refer to the most efficient change of state. 209.218.108.23 (talk) 21:27, 22 September 2011 (UTC) (Geologist)

There are some vague statements about 'reversibility' being fundamental to science. This is an interesting thought. Has anyone a counter example other than quantum phenomena? A phenomenon is a change in quantity or quality, either measurable or observable. We in geology test a proposition by finding rocks with the initial observations, then seeing whether the prediction of change is present. We use such a proposition backward, to predict the 'cause' from the 'effect'. Reversibility may fail for quantum phenomena, but if an effect can have only one cause, the proposition proves to be useful. Axiomatic theories are possible even in geology. Walter Bucher wrote one about mountain building in the early 20th Century, and it's still valid (even after the theory of Plate Tectonics). 209.218.108.23 (talk) 21:27, 22 September 2011 (UTC)(Geologist)

Equilibrium systems are homogeneous?

I doubt this. If I have a sphere half full of water, the rest air, at room temperature, what does the equilibrium state look like? Assume the center of mass is at the center of the sphere. I think it will be a sphere of water, centered at the center of the container, surrounded by air that is saturated with water vapor, assuming no interaction between the walls of the sphere and the water.

Does every part of a system have to be diathermically connected to some other part? Why can't I have a system consisting of two containers of gas, each at equilibrium, each at different temperatures, adiabatically isolated from each other? By the definition of equilibrium, the state does not change in time, so such a system is in equilibrium. PAR (talk) 03:14, 7 April 2011 (UTC)

Dear PAR, good point. The phases of equilibrium systems in the classical picture are homogeneous, but you are right, one can have a system that consists of multiple phases, and that system is, of course, not homogeneous. Accordingly, I have put in a note about phases.

As for a system consisting of two containers of gas, [each at its own isolated private equilibrium,] each at different temperatures, adiabatically isolated from each other: Yes, if you like to speak of compound systems with internal adiabatically isolating barriers, and you keep the barriers in place, and the temperatures are different, you can say that the system is in equilibrium, provided you remember to say that the barriers must be maintained. Rather than speaking of a system with internal barriers, it seems to me more natural to say that one has several systems. It creates complications for saying things, unnecessary complications as I see it, to speak of systems with maintained internal isolating barriers. The key physics here is that the elementary basic states of thermodynamics are homogeneous. Just how you like to talk about compound systems with phases and barriers is the kind of thing that can create endless complications, which you may or may not fancy. Planck, Guggenheim, and Prigogine and Defay work with systems having multiple phases, but in general not having internal isolating barriers, and I am happy to follow them in this.Chjoaygame (talk) 08:59, 7 April 2011 (UTC)

Yes, I don't have the book handy, but I believe Guggenheim makes a distinction between a general system with possibly adiabatic barriers, and a "standard system" without them. If you have the book, can you check that out? PAR (talk) 17:14, 7 April 2011 (UTC)

Dear PAR, Guggenheim's last edition (fifth, 1967, apart from a paperback published in 1985 after his death with the same content) on pages 6 and 7 writes: "To sum up, the complete description of the thermodynamic state of any system involves a description of the thermodynamic state of each of its homogeneous phases, which may be few or infinite in number." No mention of partitions or barriers. No mention of a "standard system" here. Elsewhere he talks about 'standard pressures' and so on. Fermi writes on page 3: "In order to define the state of a non-homogeneous system, one must be able to divide it into a number of homogeneous parts." No mention of partitions. Prigogine and Defay write in italics on page 1: "'By definition a phase is homogeneous or uniform throughout its extent.'" No mention of partitions. Glansdorff and Prigogine do not mention partitions. De Groot and Mazur do not mention partitions. In discussing osmosis and separation of components by use of semipermeable membranes various writers use the concept of a membrane within the system and such systems are not homogeneous but the membranes are not really isolating partitions. I vaguely recall a book about living cell thermodynamics that had its own different definition of 'phase'. Callen, discussing the vexed term 'entropy of mixing', uses a piston-like sliding semipermeable partition and a fixed partition; I don't think he gets the physics right even so: mixing two previously separated substances will have them perhaps show colligative effects, but they are colligative effects, not simply mixing effects, I think; I don't think Callen quite cottons on to this; his use of partitions doesn't get him home. Other writers about the 'entropy of mixing' also use partitions. Callen also talks about 'coupled systems' driven by pistons linked by lever arms. The machines of Carnot are in a sense 'systems' far from homogeneous, but for Carnot, the cyclic process approach exempts him from a detailed account of the 'working substance' and its machinations. Both Guggenheim (page 6) and Sommerfeld (page 3) cunningly start their remarks on such matters by referring to the the "simplest example", and talk immediately about homogeneous systems; cunningly, they don't tell us about systems that are not simple examples. I think that just how you like to talk about compound systems with phases and barriers is the kind of thing that can create endless complications, which you may or may not fancy. I don't think the Wikipedia can easily be cleverer than Guggenheim and Sommerfeld and Fermi and Prigogine.Chjoaygame (talk) 21:51, 7 April 2011 (UTC)

I found it - its in Buchdahl, "The Concepts of Classical Thermodynamics" Chapter 1.10 page 18 "Standard Systems". PAR (talk) 00:07, 8 April 2011 (UTC)

Dear PAR, on page 14 Buchdahl writes: "When convenient, two systems may of course be regarded as two parts of a composite system." And indeed on page 42 he talks of a "compound system" and says that it is non-standard. And on page 174 he talks about Joule expansion in terms of a "compound system". And on page 175 about Joule-Thomson expansion in terms of two large enclosures. And on page 176 about mixing in terms of separate compartments of a diathermal enclosure. Though he has set up a terminology of 'standard' and 'non-standard' systems, other writers do not so far as I have noticed use these terms 'standard' and 'non-standard' for systems. It seems he feels the need to explicitly notify the reader when he is referring to a compound system, and does not take 'system' by default in general to be compound. I think this is the commonest usage.Chjoaygame (talk) 07:21, 8 April 2011 (UTC)

All this terminology is unfamiliar to me. However, Gibbs (who invented chemical potentials) used, I believe the rims of phases. His derivation of the Gibbs-Duhem equation used not Euler's equation, but a simpler property of phases homogeneous, in that slicing and dicing did not affect their compositions, entropies, volumes or chemical potentials, temperatures, or pressures (ignoring surface effects). 209.218.108.23 (talk) 21:02, 22 September 2011 (UTC) (Geologist).

Sorry to take so long to read all of the above, but I just finished. Although I certainly don't disagree with any of the authorities given, I disagree with the answer.

Is homogeneity, even of intensities only, needed for equilibrium? Can I have an equilibrium system with an adiabatic partition?

Equilibrium occurs when all parts of a system have communicated as rapidly as the environment is changing. Examine the subject of osmotic pressure. You start with a system homogeneous in pressure, not at equilibrium. When equilibrium is attained, the semi-permeable membrane down the center has allowed water to cross, increasing the pressure greatly in one partition, decreasing it in the other. Why should an adiabatic, flexible barrier not be similar?

Geologist (talk) 05:51, 29 September 2011 (UTC)

Response to Geologist's question: "Is homogeneity, even of intensities only, needed for equilibrium?" According to the usual suspects, in the absence of an externally imposed force field such as gravity, a simple isolated system of a single phase in thermodynamic equilibrium is homogeneous. In the presence of an externally imposed force field such as gravity, the matter will tend more or less to sink to the bottom, as noted by Aristotle. Accordingly the density and so forth are not homogeneous. But the temperature will be uniform.Chjoaygame (talk) 07:27, 29 September 2011 (UTC)

Unfortunately, in this example, the phase (immersed in a saturated solution) will probably dissolve at the bottom (where the stress is greater), and precipitate on the top (where it is not). Hence the system is not in equilibrium either; and it doesn't use purely internal energy, which most texts like. We can find a good example anyway:--

Osmotic equilibrium illustrates a system that is at chemical equilibrium, yet not chemically homogeneous (a term which includes pressure). Hence homogeneity is not needed for equilibrium. Geologist (talk) 17:56, 29 September 2011 (UTC)

Most of your 'usual suspects' are likely chemists. If you pick up a rock, the only homogeneous phase visible is likely quartz. When a mineral is compositionally zoned, the inner part of a zone was probably metastable (or even unstable) at the time of crystallization. Once this 'nucleus' is present, the mineral changes composition as it grows until it reaches a stable equilibrium, when it pauses. Geologists use composition-measuring microscopes to capture this stable composition and calculate the temperature and pressure of an assemblage of such compositions, or of a hand specimen of rock. This stable zone (but not the phase, or even crystal) is homogeneous in your suspects' sense, so osmotic equilibrium presents a better example. Geologist (talk) 18:22, 29 September 2011 (UTC)

Response to Geologist. Thank you for your response. My usual suspects in this case are Maxwell, Gibbs, Boltzmann, Planck, and Guggenheim. I did not offer a yes-no answer to your question. I just offered a response to it. But indeed I agree that concentration homogeneity is not needed for equilibrium, although uniformity of temperature is needed. Nevertheless, I think my response missed the direction of your interest. I would say that your interest seems directed to questions of how to define a simple or compound system and a phase and a component. You also seem to have a special definition of equilibrium, suited for geology, I think, which is not quite the same as the simple definition of thermodynamic equilibrium used by the usual suspects. This seems to be shaping up as a reason for someone to put something about thermodynamics into the article on Geology.Chjoaygame (talk) 20:02, 29 September 2011 (UTC)

Technically, I've not asked any questions; I've tried to lead your mind into recognizing your own errors. Enough has been presented to clarify my position, which is that, however equilibrium is defined (mine is Fermi's), composition, pressure, and temperature must be symmetrical, equivalent variables. Consequently, despite the Zeroth Law's apparently confusing you, uniformity of temperature is not needed for equilibrium ..if.. there is an adiabatic wall present.

Thank you for pointing out, repeatedly, that there exists an article called 'Geology', where I should be spending my time instead of here. However, that article is well written and competent. The 'petrology' section covers my favorite subject nicely: we have continued the work of the physicist Bridgman, and use (of course) the theories of the physical sciences as tools, as does every natural science. Geology is a natural science of great complexity; and I don't think one needs to tell people that it must draw upon thermodynamics and other useful theories. You are welcome to do so, however. Geologist (talk) 21:09, 29 September 2011 (UTC)

Under 'Treatment of Equilibrium', the article reads:

'Most systems found in nature are not in thermodynamic equilibrium; for they are changing or can be triggered to change over time, and are continuously and discontinuously subject to flux of matter and energy to and from other systems. For their thermodynamic study, more general concepts are required for non-equilibrium systems than for equilibrium systems.'

Geologists do just fine with equilibrium thermodynamics. They apply it to metamorphic and igneous rocks the size of a hand specimen. I don't expect this statement changed. Many geologists, too, consider texts & treatises to be written by divinities. They have the problem that the earth, from its deepest samples to a sample bottle in an estuary, demonstrates consistent results that would satisfy any scientist as proof of equilibrium. Rats! How can that be?

Geologists who have not carefully studied Fermi explain this by a failure to attain equilbrium, but an inability to measure a deviation from it. (This is in the fine print in geothermobarometry. Just ignore the ancient folklore there of minerals having to be in contact.) This failure to attain equilibrium is, of course, Bridgman's definition of equilibrium itself; but philosophers of science roll their eyes at such a concept. Still, rocks change their compositions with position and with time, but rarely fast enough for equilibrium to fail and keep up. Most triggers (metastable states) have already been set off (earthquakes are nearly continuous) for both continuous and discontinuous changes in state. The study of crystals in magmas (where no shear waves contributed to triggers) allow stable equilibrium states to be identified.

Spacial and temporal deviations are not really extant in the laboratory, especially when the footfalls of students are permitted; so chemists and physicists don't really work with systems the size or age of a mountain. If they did, equilibrium might have been defined differently. I suggest what you will likely do: keep it wrong until a different definition reaches reputable treatises. However, your conclusion implies that equilibrium thermodynamics is not very useful in geology, which is certainly wrong; and I'm not sure what to do about this logical conclusion.

All non-equilibrium thermodynamics come with deep problems of their own, since the concept of temperature assumes equilibrium. Applying them rather than equilibrium thermodynamics to the earth would not guarantee better results.

Geologist (talk) 05:43, 4 October 2011 (UTC)

Oh, I found a statement in thermodynamic equilibrium that similar to Fermi's classical definition, but draws from a different theory of thermodynamics (mixing two or three theories):

'Local thermodynamic equilibrium does not require either local or global stationarity. In other words, each small locality need not have a constant temperature. However, it does require that each small locality change slowly enough to practically sustain its local Maxwell-Boltzmann distribution of molecular velocities.'

This raises the problem of offering consistency throughout the Wikipedia, a problem I'm sure has been addressed thoroughly (though I confess ignorance of any policy). Geologist (talk) 06:57, 4 October 2011 (UTC)

The consensus of geologists, I believe, will welcome Chjoaygame's edit: Thanks! Perhaps practitioners of other natural and applied sciences could list the theory of thermodynamics their field benefits most from. Geologist (talk) 20:00, 4 October 2011 (UTC)

An Equilibrium Equivalent to minimizing the Characteristic Function

Abstract to concrete classical thermodynamics define equilibrium as states that minimize a characteristic function (Prigogine & Defay). A large body of consistent pressures & temperatures suggests this works for geologists; and these concrete to abstract definitions of equilibrium do have an equivalent, on page 4 of E. Fermi's 1936 Thermodynamics by Prentice-Hall in NJ: [States of equilibrium] have the property of not varying so long as the external conditions remain unchanged. ... 'A reversible transformation can be realized in practice by changing the external conditions so slowly that the system has time to adjust itself gradually to the altered conditions.' (What is the speed of chemical diffusion & crystallization in a hand specimen of mudstone that's dissolving micas, relative to the speed of temperature & pressure changes in a slowly subducting slab of underlying oceanic crust?

How fast can your Ferrari speed in bumper-to-bumper Los Angeles traffic? :-) Geologist (talk) 07:02, 31 October 2011 (UTC)

Thermodynamics is a simple subject

Classical thermodynamics, as presented in universities, is really a simple subject: work degrades to heat. Examined logically, the subject is fundamentally confounding (as presented in P.W. Bridgman's works). Its two laws and such concepts as 'temperature', needed to define heat, require equilibrium. This is why axiomatic presentations assume equilibrium.

The term 'adiabatic', BTW, does not imply rigid. This comprehensive presentation needs to be edited heavily by a physicist or physical chemist. It merely alludes to thermodynamics, mixing elementary and advanced concepts, often the same sentence. Almost always, facts presented are wrong. I truly don't mean to be cruel: great effort was taken in writing this; and a good re-write can draw from its topics. Thermodynamics can appear very confusing in texts that focus more on its successful application than concepts. Prigogine & Defay, for example, state the phase rule is applicable to open or closed systems, while the eminent Glasstone states closed only. (P&D are correct.)

The article is of such great importance that it needs to be written by a fine physics professor, one who has spent his career presenting it simply to students. (I am only a retired geologist.)

209.218.108.23 (talk) 17:50, 22 September 2011 (UTC) ('Geologist')

Perhaps, dear Geologist, since you find thermodynamics simple, and seem familiar with Prigogine and Defay, you will be very kind, and, in intuitively understandable terms, for our education, gently clarify for us Chapter XVII especially Section 3 of that textbook? My particular puzzlement is with the sentence: "However, if the mixture is rich in nitrogen (...) then the addition of a little more nitrogen is followed by a further dissociation of ammonia to form more nitrogen and oxygen." While I am not doubting its truth, I have to admit that this does not feel intuitive to me; perhaps you will be so very kind as to explain it so as to make it feel intuitive to me. Also, perhaps you may like to create a Wikipedia account, that, amongst other things, will, when you use the four tilde signature method, automatically post your preferred pen-name without disclosing your IP address; you can choose a pen-name that will give no hint of your personal identity.58.164.118.92 (talk) 11:58, 23 September 2011 (UTC)

Sorry about the confusion. I assumed the article was to cover fundamentals. Notice I wrote: 'Thermodynamics can appear very confusing in texts that focus more on its successful application than concepts.' I've neither my library or computers, but your question emphasizes this statement.

As in dynamics, thermodynamic objects appear to resist being jostled about. Hence, if a chemical mixture can react, it will do so to ameliorate a perturbation of its thermodynamic quantities. Adding nitrogen will increase its escaping tendency (fugacity) if no reactions take place. If it can react, it will do so to reduce this increase. In cases of reacting gasses, single or multiple reactions can greatly increase or decrease pressure and concentration. In your case 'if rich in nitrogen' suggests the chemical compounds (which comprise the mechanisms of change accessible to the system - the reactions) change with bulk composition. To be quick, in cases such as yours, although the amount of nitrogen increases, the amounts of other gasses may increase more: this (ignoring pressure), reduces the reaction-free increase in concentration and escaping tendency of nitrogen, as the Le Chatelier-Braun Principle predicts. If not, examine the pressure change (though changes in pressure and composition are highly correlated in gasses).

The above assumes equilibrium and has something to do with the second law, though you have me there. Derivations are difficult. That's why I claim thermodynamics (without too much analysis) is simple; it's applying it that's hard. However, I found the article very complicated and jargon-riddled.

Apologies again, but I've neither my computers nor password book, but I'm registered as 'Geologist'. If you wish to discuss your question further, my e-mail is in my personal data on the Apple Boards under 'Bruce Bathurst'. (I seldom use handles except on sites where I anticipated being hated. :-)

Don't hesitate to write. But remember, I'm only a geologist. We too, however, use thermodynamics now & then. 209.218.108.23 (talk) 16:03, 23 September 2011 (UTC) (Geologist)

Thank you Geologist. As I interpret what you write, you seem to have a statement of the LeChâtelier-Braun principle different from Prigogine and Defay's. It seems that the exact wording of the principle matters. You find Prigogine and Defay here to be very complicated and jargon-riddled. It seems to me that a responsive increase in the amount of nitrogen would increase its fugacity at constant volume, but they here refer to a process at constant temperature and pressure (first paragraph of section 3). In effect, you are saying that at constant temperature and pressure with a nitrogen-rich mixture, the response to the perturbation will be an increase in volume that will reduce the concentration of nitrogen so as to partly negate the perturbational increase in nitrogen concentration, even though the amount of nitrogen has increased; the newly produced hydrogen will dilute the nitrogen. Thus you are defining the perturbation as a perturbation of fugacity, while Prigogine and Defay define it as a perturbation of amount of nitrogen (their words are "number of moles"). They comment: "Many workers have attempted to state the principle in completely general form; but this form, if it exists, is necessarily very complex." They also comment that "Analogous considerations apply ... at constant volume." It calls for very careful statements.Chjoaygame (talk) 17:24, 23 September 2011 (UTC)

As I said, I'm sorry not to have any books with me. 'I found the article very complicated and jargon-riddled.' refers to the Wikipedia article. You asked for a clarification, not a rigorous explanation (which you have), and you didn't specify the nature of the walls that contained your gas (hence I chose closed, rigid, and adiabatic, to ease the explanation). Your misquotes of me mix 'walls', or partial derivatives.

Any consistent coordinate system is easily converted into Progogine & Defay's definition, though they aren't gods: different natural sciences have need for the Le Chatelier-Braun principle in different variables. If it were valid only for your variables, it would be an empirical approximation, not a scientific theorem. P&G would, I believe, agree.

Just for those interested, the crux of the solution is likely the change in reactions accessible to the system at high nitrogen compositions.

I oppose trolling, so you are quite free to misquote me again. My comments were completed earlier, though I feel I could have been a bit harsh about the errors in the article. However, my good faith is exhausted: because I feel you are attempting to discredit my qualifications, I'll return to mulching my violets. Feel free to have my comments deleted. Have a nice day. -Bruce Bathurst (Geologist) http://en.wikipedia.org/wiki/User:Bruce_Bathurst.

Bruce Bathurst, thank you for this. I didn't realize you didn't have Prigogine and Defay with you. I had not then noticed your comment that you did not have your library with you; I am sorry for that. I didn't specify the nature of the walls because I was expecting you to look at the chapter in the text, not taking into account that you don't have the text with you. I didn't mean to misquote you. I guess that you are referring to my sentence "You find Prigogine and Defay here to be very complicated and jargon-riddled."? I didn't realize the words "very complicated and jargon-riddled" referred to the Wikipedia article. You had changed the subject, from the Le Châtelier-Braun principle to the Wikipedia article, so I can be forgiven for thinking you were still referring to Prigogine and Defay's article on the Le Châtelier-Braun principle in Section 3 of their Chapter XVII.

You write:

"Any consistent coordinate system is easily converted into Progogine & Defay's definition, though they aren't gods: different natural sciences have need for the Le Chatelier-Braun principle in different variables. If it were valid only for your variables, it would be an empirical approximation, not a scientific theorem. P&G would, I believe, agree.

"Just for those interested, the crux of the solution is likely the change in reactions accessible to the system at high nitrogen compositions."

I think it would be easier if you had the text with you. The matter is too complicated to work on by guess and remote control. They are not "my" variables; they are Prigogine and Defay's.

I think that you do indeed have a different, and perhaps better, statement of the principle than the one that Prigogine and Defay use. They say explicitly that their principle has exceptions and that this is one of them; it is a large part of the message of their Chapter. Prigogine and Defay comment that they do not know how to state the principle in an exceptionless way. It seems your principle may be exceptionless, though that is a statement that I do not feel I have enough understanding to form a judgement about.

I am sorry you feel I am attempting to discredit your qualifications. My own feeling at the time I wrote and after I wrote my response to your answer to my question was "Thank God we have someone here who really knows what he is talking about, and gave a very good answer to my question, though it was a bit careless of him not to bother to look at Chapter XVII before answering. (As I said above, I had not then noticed your comment that you did not have your library with you; I am sorry for that.)" So I can say you mistook my intention. Yes, I did think you had been rather peremptory in your comments: you say they "could have been a bit harsh". No way would I seek to have your comments deleted. Why would I? Of course I have not the slightest intention of misquoting you. Why would I? I continue to think that your answer to my question was very helpful and insightful. The first sentence of my response thanked you for it.Chjoaygame (talk) 22:45, 23 September 2011 (UTC)

If editor Geologist (aka Bruce Bathurst) is still reading this page, he might like to observe that there is, as far as I can find, no mention of thermodynamics in the Wikipedia article on Geology. Perhaps someone might do something about that.Chjoaygame (talk) 07:44, 27 September 2011 (UTC)

I'm back. I've Prigogine & Defay in my hand; and I realize I misled you. Glancing at the following chapter, P&D appears to be referring to an open system here. Section 3 makes this clear in its introduction and ends with the puzzling equation 17.25.

Le Chatelier's and van't Hoff's principles correlate extensive variables with their intensive conjugates (volume & pressure; entropy & temperature, respectively). Quantity of substance is correlated with chemical escaping tendency; but if the system is open, there is no correlation at all. In the case of walls that are open to nitrogen, pushing nitrogen through one side will push an equilibrium mixture out the other.

I think 17.25 is simpler if both sides are inverted, so x(i) lt v(i)/v. Now we can see that, if adding nitrogen uses it to create NH3 (the bulk compositions shifts toward NH3), the system behaves as intuition suggests; but if adding nitrogen causes NH3 to decompose and produce H2 (the bulk composition shifts away from NH3), N2 will also be produced. A binary phase diagram N2-H2 should clarify this. P&D is filled with phase diagrams, but I can't find a good example.

Also, I don't pretend to be comfortable with the above explanation (after one reading). I should read the references (which are always easier), and try some examples using gas mixtures you're familiar with.

However, I hope this correction helps some: the question confused me until I realized the system was open. P&G doesn't offer a nice explanation in anything but symbols. :-( My best,

Geologist (talk) 22:15, 2 October 2011 (UTC)

Thank you for this, Geologist. Yes, indeed P&D say they are referring to an open system; I didn't go into such detail before, for more or less obvious reasons. I suppose it must make a difference, but I am not clear what kind of walls and open system they refer to, and what they intend for its surroundings. I have not chased up the references.Chjoaygame (talk) 04:03, 3 October 2011 (UTC)

This is true. Another simple subject is the board game 'Go', with two colors of stone and a single rule. Yet mastering its application to games takes decades. I suspect no texts have more errors than those of thermodynamics. (I've not found one in P&D.) Long ago, some friends taught me to return to the original discovery, which must explain the topic clearly to have convinced the reviewers. (BTW, those references are mainly Dutch, I believe, published in French.)

If you're happy with a vague explanation, try this: In closed systems, two reactions (assuming O2) can proceed in such relative amounts that both drop the characteristic potential (by reactions) and increase the amount of nitrogen. Opening a system to a composition adds another tool to its box of tricks, allowing the system to both drop the characteristic potential (by single reaction and diffusion) and increase the amount of nitrogen. (That might explain why P&D's treatment had to be so terse as to fit in only two chapters!-) Geologist (talk) 20:34, 3 October 2011 (UTC)

"(assuming O2)" What is this?Chjoaygame (talk) 21:03, 3 October 2011 (UTC)

It was the error in your original query that led me to consider the crux of the solution to be a change in a system of two reactions (which is common). Don't worry about it. Geologist (talk) 22:30, 3 October 2011 (UTC)

Removed erroneous conclusion

According to Herbert Callen's widely cited 1985 text on thermodynamics: "An essential prerequisite for the measurability of energy is the existence of walls that do not permit transfer of energy in the form of heat." This makes the recognition of heat and temperature a necessary presupposition for the proper statement of an empirically testable principle of conservation of energy..

I have removed the second sentence which is an erroneous conclusion. What Callen meant was that the existence of walls that do not permit the transfer of energy are fundamental, and do not require the concepts of heat or temperature, or entropy, in order to be used. If this were not the case, then there would be circular reasoning. You would need to define heat and temperature in order to state the first law, which then defines heat, which then lays the groundwork for the second law which defines temperature. PAR (talk) 00:57, 28 September 2011 (UTC)

What is this talk about circular reasoning? The notion of walls that do not permit the transfer of energy requires the concept of energy. The concept of energy is built on a notion of conservation, and if you assume the conservation of energy, then it becomes nonsense to try to verify it experimentally, which Callen does by use of the concept of state. Callen's definition of state in his Postulate 1 on page contains the variable the internal energy. This is a "non-deformation coordinate" and satisfies the definition of an empirical temperature under the conditions used. I will content myself with quoting the two sentences of Callen just previous to the one that is quoted in the article: "In order that this energy function be meaningful in a practical sense, however, we must convince ourselves that it is macroscopically controllable and measurable. We shall now show that practical methods of measurement of the energy do exist, and in doing so we shall be led to a quantitative operational definition of heat." He then argues in physical terms with the use of the concept of heat, though not measured on an absolute scale. He says further on "The existence of these several types of walls [diathermal and adiabatic] resolves the first of our concerns with the thermodynamic energy. That is, these walls demonstrate that energy is macroscopically controllable. It can be trapped by restrictive walls and manipulated by diathermal walls." How can you distinguish diathermal from adiabatic walls without recognizing heat and empirical temperature and without assuming the law of conservation of energy? You are misrepresenting Callen on this point. In effect, you are calling Planck a silly old fool.

PAR, by imposing, by force of overwriting, the doctrine that comes from your point of view, you may get a feeling of satisfaction, and perhaps approbation from your fellow believers, but this is not science, and I do not have time to struggle with it. I will not fight you over this, since you have already convincingly demonstrated that you have immediate access to control over these articles through an old-boy network in contempt of the policy of reliable sources and the policy of reasoning discussion on the talk page.Chjoaygame (talk) 06:05, 28 September 2011 (UTC)

Editor PAR has done an good job of allowing the article to "show" the points raised by reliable sources rather than "tell" those same points. This does a nice job of keeping PAR's own point of view out of the article, and simply doing the right thing as a Wikipedia editor. I am concerned that editor Chjoaygame is in fact the one attempting to promote some strange doctrine and I would respectfully request that editor Chjoaygame cease in this activity. 128.231.77.189 (talk) 16:48, 28 September 2011 (UTC)

I've no books, but I shall quote you:

'According to Herbert Callen's widely cited 1985 text on thermodynamics: "An essential prerequisite for the measurability of energy is the existence of walls that do not permit transfer of energy in the form of heat." This makes the recognition of heat and temperature a necessary presupposition for the proper statement of an empirically testable principle of conservation of energy... .'

Axiomatic presentations are composed of axioms and primitive definitions that one assumes are true. Logic them develops these. However, I'm a operationalist, so I like a little more.

The essence of your question is: Can one find an adiabatic wall without having a way of measuring heat? Imagine a balloon made of different substances, each permitting heat to pass to varying degrees. Let the environment change (lowering & increasing its pressure), so the balloon expands and contracts. That balloon which expands most is closest to adiabatic. (In your language, work that produces heat in the balloon can't escape, and enlarges the balloon as temperature and pressure return to their initial values (lots of tiny system tossed throughout the environment are again identical, defining a cycle.) Drawing graphs, we might even be able to define 'adiabatic' as a limit.

The above has the advantage of defining work as well, given the mechanical properties of the balloon. Ordinary, closed balloons with change in size and warmth during the cycle, so there exists thermodynamics quantities that form a potential: they return to their initial state(s) as the environment makes a cycle. A clever person will note that we can, if we choose, invent 'heat', which when summed with work, is a potential. One can also integrate Joseph Black's specific heats over relative temperature changes to calculate heat independently. But this isn't necessary. This derives the first law of thermodynamics from a system surrounded by an adiabatic, closed wall only, not necessarily from concepts of heat or temperature.

The above is awkward, for I haven't Callen with me, but it illustrates that walls suffice to express the laws of thermodynamics. Heat & work are a more historical alternative, but we use Black's integration to calculate heat flow from a temperature difference (and heat flux can't be separated into radiation and conduction, as done in one draft of the article). So, axiomatic presentations can become circular very easily.

(My personal axiomatization uses volume change and thermometers, not walls. This permits me to eliminate the 'Zeroth Law' by blending it into the definition of temperature. Also, you should eliminate the 'Third Law' from the article. However, PAR, I believe, is correct here.)

PS. I missed the part where PAR calls Max Planck a 'silly, old fool'.

Geologist (talk) 21:54, 28 September 2011 (UTC)

Chjoaygame, I have called in the "old boy" network only once, and that was because you made the statement that the first law is not about conservation of energy, which is flat wrong, and I was not willing to allow such a blatantly incorrect statement to exist on that page while we discussed the matter. Many of those "old boys" I do not recognize, some I do recognize and have had conflicts with in the past, and some of those conflicts I did not win. So please do not think that there is some kind of mindless gang of robots running around reverting edits that do not agree with their unexamined dogma. The thing about this gang is that they usually resolve disputes by reasoned arguments, rather that trying to beat each other to death with quotes from famous people that they do not understand.

I am more than willing to rationally discuss this with you, but please do not tell me I am wrong because I disagree with some famous person. If that famous person was correct, then there is a reasoned argument that proves that I am wrong. Please give me that reasoned argument. My philosophy is that of Buddha:

Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense - Siddhartha Gautama Buddha -

If your response is to request a reference for that quote, or to point out that it is not a correct translation, or that Buddha is not a reliable authority, then you have missed the point entirely, and we have nothing more to discuss.

You say: "The notion of walls that do not permit the transfer of energy requires the concept of energy." True, but the fundamental notion is not that they do not permit the transfer of energy, but rather that two systems on either side of the adiabatic wall do not equilibrate. Equilibration, thermal contact and thermal isolation are fundamental concepts. Bruce Bathurst has given a very good example, and we should study it, rather that searching for quote from some book which seems to contradict it. If his argument has flaws, then we point out the flaws. I admit that the process of precisely defining equilibrium, thermal isolation and connection in terms of measurements which do not use the concepts of energy, temperature, entropy, etc. is not wholly clear to me and I am trying to understand it myself. I am adamant that circular reasoning is not acceptable. I am open to any reformulation of thermodynamics. I am willing to throw out all of the laws of thermodynamics and start from scratch, but I will not settle for circular reasoning and I will not settle for quotes from famous people which seem to contradict my understanding without asking for a rational explanation. PAR (talk) 00:36, 29 September 2011 (UTC)

Oh, my argument has flaws. Let me point them out before being flogged. (Remember, it's been decades since I've read Callen.) It's fairly easy to use walls to derive the first law; but that leaves you adrift in mathematical abstraction. Here's why.

Thermodynamics is simple to derive by differentiating energy to S, V, &c, then T, -p, &c, then specific heats. Energy is very abstract, and difficult to comprehend. This is differentiating left to right. The really hard part is using it to solve problems.

Historically, and operationally, thermodynamics can be presented by integrating the above quantities right to left. This presentation is not as elegant, but is closer to applications. Operationally, you need temperature to calculate heat flux. Consequently, if you create an axiomatic presentation (which is not for teaching), the reasoning will always be circular if you take the easy route: to measure an object, you need an object derived by differentiation that you have not yet defined.

My preferred method of teaching is to solve famous problems in petrology using only necessary and sufficient quantities. Each solution to a problem is therefore a proof to a theorem, a theorem of value in geology. My personal axiomatic theory starts with volume, and integrates. By defining temperature from the operations used to measure it, I move the zeroth law to this definition, eliminating an axiom. I also suggest you eliminate the so-called 'third law'.

Note also that, if not already corrected, you should separate classical, non-equilibriums (there were many), and statistical thermodynamics (the many)--I would discuss only classical, equilibrium thermodynamics, develop the theory from either left or right (not both), not distinguish heat flow and radiation when discussing the flux of heat (for experiments can't, to my knowledge), and decide whether to explain fundamentals or discuss obscure applications; but don't try both. If Chjoaygame takes the historical approach, I would probably support that--if simplified greatly. Just some ideas to think about.

Geologist (talk) 01:35, 29 September 2011 (UTC)

BTW, I never understood science until I read D.T. Suzuki's 'Outline of Mahayana Buddhism'. However, I do not recommend reading it: there are far easier, more appropriate works. :-)

Also, because Chjoaygame doesn't have a User page, I wish to tell him that I think I changed his answer to the query of whether equilibrium systems can be thermally heterogeneous in 'Equilibrium systems are homogeneous?' from (I think) no, to yes.

Geologist (talk) 01:42, 29 September 2011 (UTC)

Response to PAR's comment: "you made the statement that the first law is not about conservation of energy, which is flat wrong." Dear Par, most of what you have said above I am letting go to the wicketkeeper, but this one is bodyline. You have utterly misunderstood my explicit statements, utterly misquoted me, when you write this. I don't know what has got into you that you misquote me so. I really don't know where you got it from that I said that the first law is not about conservation of energy. Indeed, the line that I wrote in response to your desire to see more emphasis on energy conservation was "The first law of thermodynamics tells how transfers of heat and work between thermodynamic systems conserve energy."

Let me be clear, in case re-reading is not enough to clarify it: I think and always have thought, that the first law is about conservation of energy. But a statement that 'the first law of thermodynamics is the law of conservation of energy', pure and simple, would be wrong, though it now seems to have won the day, largely in consequence of your efforts. If it were right, then we would be talking about merging the two articles, which we are not. The first law of thermodynamics is a law of thermodynamics and deserves to be stated as such, even though it is about conservation of energy.

As you have said and as I have agreed explicitly, the first law of thermodynamics is a statement of the law of conservation of energy applied to thermodynamics.

You wrote:"Just to be sure, do we agree that the first law is a particular case of the general law of conservation of energy? In other words, the general law includes all forms of energy, including thermal energy, while the first law is a particular case which specifically includes thermal energy."

I replied: "Yes, or nearly yes. The first law is a particular case of the general law of conservation of energy. It specifically refers to transfers of energy as heat and as work. The phrase "thermal energy" should be used to refer specifically to transfer of energy, because otherwise it might be hard to define in some circumstances."

The term "thermal energy" is not quite according to the MCC laws in an introductory article on thermodynamics, and that is the reason for my reservation "or nearly yes". "Thermal energy", in the present context, is a possibly confusing term: often it is used to refer to a virtual decomposition of internal energy into a 'potential energy' term and a 'molecular kinetic energy' term; though not utterly wrong, that decomposition applies only in very restricted way, and is not straight up and down the line of the wicket thermodynamics.Chjoaygame (talk) 13:21, 29 September 2011 (UTC)

Well, I am responsible for it, but we shouldn't discuss past edits to other pages on this page. I do not mean to misquote or misunderstand you, and I will let the discussion on the first law page speak for itself. PAR (talk) 13:37, 29 September 2011 (UTC)