Talk:Second law of thermodynamics

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Contents

Overhaul[edit]

I am now working on an overhaul of the article. Anyone is welcome to see my draft and edit or give advice.--Netheril96 (talk) 03:44, 9 October 2010 (UTC)

Well, when you write "In each adiabatically separated compartment, the temperature becomes spatially homogeneous, even in the presence of the externally imposed unchanging external force field" you are mistaken because there is a redistribution of energy such that the mean sum of molecular gravitational potential energy and molecular kinetic energy is homogeneous, and thus there is a redistribution of temperature, becoming cooler at the top. This is because changes in gravitational potential energy in molecular flight between collisions cause changes in entropy. This is why and how there is a huge temperature difference in the cross section of a Ranque Hilsch vortex tube wherein a huge force field is generated artificially.

From your introduction one could conclude there are two distinct and very different types of entropy.. so different that you say "Don't mix thermodynamics and statistical mechanics up". This is misleading because it hides the fact that the heat expression for entropy is actually only a special case of the statistical expression! A significant point which should be included. (Vh mby (talk) 03:09, 27 April 2011 (UTC))

Actually the second law has been justified on macro terms having no relation to statistical thermodynamics. See, for example <http://physics.stackexchange.com/questions/5614/references-about-rigorous-thermodynamics> , and more specifically <http://arxiv.org/PS_cache/math-ph/pdf/9805/9805005v1.pdf>

THERMODYNAMIC equilibrium is characterized by maximum entropy (within system constraints) and thus a lack of any unbalanced energy potentials. It can never be an isothermal state in a vertical plane in a gravitational field. (Such is never seen in the troposphere of any planet, for example.) This is because mean gravitational potential energy (per molecule) must be taken into account and it would cause an unbalanced energy potential in a vertical plane if mean kinetic energy were homogeneous. The gain in potential energy must be offset by a loss in kinetic energy, and indeed this transition takes place in every movement of molecules between collisions. Hence, at thermodynamic equilibrium the Second Law implies (as a direct corollary) that there will be a density gradient and a temperature gradient. A pressure gradient follows as a corollary of these two gradients, because pressure is proportional to the product of temperature and density. If what I'm saying were not correct, then you cannot explain the necessary energy input at the base of the nominal troposphere of Uranus where it's hotter than Earth's surface, but there is no direct Solar energy nor any internal energy source of any convincingly detectable magnitude. What happens is that new solar energy absorbed near the top of the Uranus atmosphere disturbs the thermodynamic equilibrium (with its associated temperature gradient) and here is indeed then a heat transfer from cooler to warmer regions because such a transfer is necessary to achieve a new state of thermodynamic equilibrium with the same temperature gradient but a higher overall temperature level. The same happens on Venus and Earth. — Preceding unsigned comment added by 121.217.3.117 (talk) 08:18, 13 October 2014 (UTC)

I am leaving the above comment about unbalanced energy potentials in the location where it was misplaced by its writer, who did not sign with a user name. Perhaps the comment is from a banned user. It is not valid in physics. Perhaps it may help if I say that I moved the previous comment, which perhaps came from the same writer, to the bottom of this talk page, which is the customary place for new comments, not the top of the page as this one is placed.Chjoaygame (talk) 10:40, 13 October 2014 (UTC)Chjoaygame (talk) 10:46, 13 October 2014 (UTC)

Yes it is valid physics written by a qualified physicist with decades of experience in thermodynamics. Your assertive statement is without any foundation in the laws of physics. Gravitational potential energy is one of the forms of energy which must be taken into account in determining when thermodynamic equilibrium is attained. If you think not, then edit the Wikipedia article on thermodynamic equilibrium if you want to mislead people.

Clausius statement[edit]

The "hot to cold" statement is merely a corollary which has certain prerequisites. Because thermodynamic equilibrium involves all forms of energy, this Clausius statement is only applicable for non-radiative heat transfer if the gravitational potential energy remains constant.


— Preceding unsigned comment added by 121.218.41.105 (talk) 09:01, 11 October 2014 (UTC)

Th equations for thermodynamic potentials specifically exclude changes in gravitational potential energy. Yet one of these, namely the entropy equation is used to prove the Clausius statement. Hence the Clausius statement is merely a corollary of the Second Law which only applies in a horizontal plane. — Preceding unsigned comment added by 101.161.181.169 (talk) 10:36, 8 February 2015 (UTC)

Hi Mister 101.161.181.169! The current version of the Thermodynamic Potential article says gravitational potential energy is "typically disregarded," but just because something isn't mentioned, that doesn't mean it's "specifically excluded." Head to section 1.3 of Alberty's pretty paper at [1], take a look at Table 1, and there's a nice mgh there for the contribution of gravitational mechanical work to thermodynamic internal energy. Yay! When you wrote "a horizontal plane," you probably meant h, but g or m could change and everything else in Alberty's table could also change. Simple things are easier to understand, so why bother with anything in Alberty's table 1 when thinking about or writing about the second law? However, I think I understand where you're coming from. What I don't like in the Clausius statement in this article is that it is not correct. The article states that entropy increases or remains constant for isolated systems and that the entropy of the universe will reach a maximum. The reality is that entropy increases or remains constant for adiabatically closed systems and it reaches a maximum for isolated systems. The phrase "adiabatically closed" allows for work interactions like everything in Alberty's table, including your mgh. Yay! Gravity CAN get involved in a system, and its entropy will still increase or remain the same according to the second law. The term "isolated" excludes everything in Alberty's table 1. Boo. If gravity keeps getting involved adding work to a system then entropy might not ever reach a maximum. I pointed this out back in 2006 at Talk:Second_law_of_thermodynamics/Archive_2#Rigor_about_isolated_vs_closed_adiabatic but it's not surprising that it hasn't been corrected yet. Such is life. If you want to learn thermodynamics, take an engineering course at a good college. Certain details at Wikipedia about science in general and thermo in particular have never been rigorous and won't be changing any time soon. Flying Jazz (talk) 21:38, 8 February 2015 (UTC)

The Clausius statement is crystal clear and should be beyond any discusson, as it is a LAW of NatURe! I admit that translating such a beautifully clear statement phrased in Clausius's own language (for Clausius it is german) is easier and that complex abstract concepts like the 2nd law will suffer in translation. This is no excuse to get it all wrong like Kelvin. Although his 'offical' statement is ok, all his propagation is outright WRONG. Kelvin caused governments to write outright illegal laws. Illegal by the terms of the universe! He caused a most despicable misconeption of laws of nature throughout all foremost english speaking countries! Kelvin's proagations and concepts are in their gist severely wrong; whereas The second Law stands as a law of nature in all its beatuy.

  • If you are going to insist that the zeroth law completely defines temperature, you must at least reference the statement. And by reference, I mean a reference which lays out the development of temperature as a real number from the zeroth law, not simply a bare unsupported statement. If temperature is

not defined by the zeroth or first law, then it cannot be used in a statement of the second law.

  • Do not eliminate a clearly referenced statement by simply declaring the source outdated. The truth of a statement is not a function of how old it is. Please at least explain in what sense the statement has been rendered untrue. The first Clausius statement is older than the referenced statement. Is it too outdated?
  • The referenced statement was not a verbatim copy added without thought. It is a very clear restatement of what was said in the reference, rendered in the third person, with modifications and clarifications. The statement actually says something. Please read the statement and point out its flaws. PAR (talk) 12:47, 2 November 2010 (UTC)

PS - to be accurate, a referenced statement was deleted, not replaced, the summary is wrong in this sense. PAR (talk) 13:10, 2 November 2010 (UTC)

I still disagree with you that temperature is "undefined" before second law, but the ordering of temperature indeed is undefined, so the reformulation of Clausius statement excluding the concept of "hot and cold" is acceptable, in my opinion.--Netheril96 (talk) 14:13, 2 November 2010 (UTC)

"Proof"[edit]

This is a bit out of my area, but should it be a concern that having lost every instance of the word "proof" from the article last month, the lead now says "There is no formal proof for the second law."? --McGeddon (talk) 10:24, 9 November 2010 (UTC)

The second law is a basic law of physics, so how can you prove it? The sentence "There is no formal proof for the second law" is inappropriate, though.--Netheril96 (talk) 10:48, 9 November 2010 (UTC)
No proof? Rubbish. Classically there was no proof since the atomic behaviour was a black box. Quantum mechanically, though, the proof is trivial, and is sourced in the article. --Michael C. Price talk 12:40, 9 November 2010 (UTC)
Don't mix thermodynamics and statistical mechanics up. In thermodynamics the second law is a fundamental law, or axiom; while in statistical mechanics it is derived from the equal probability postulate. It is better not to mention whether it is provable or not in the article.--Netheril96 (talk) 13:04, 9 November 2010 (UTC)
The only meaningful distinction between thermodynamics and statistical mechanics here is that the former is classical, the latter quantal. So perhaps we should say that there is no proof classically, but that it can be proved from QM. --Michael C. Price talk 17:27, 9 November 2010 (UTC)
The current lead is OK.--Netheril96 (talk) 13:05, 9 November 2010 (UTC)
Actually I don't think the lead is okay. It states that the 2nd law relies on the assumption "that all accessible states of an isolated system are a priori equally likely" which is a bit vague (requires equilibrium?) and begs the question of why that is a reasonable assumption. A better proof/derivation is from unitarity, which the article already mentions. Any objections to mentioning that in the lead? --Michael C. Price talk 17:23, 9 November 2010 (UTC)
The term proof might mean different concepts in different fields and I think it is best to avoid the term when it comes to physical laws or axioms. For a physicist deriving thermodynamics from another theoretical framework, such as QM might constitute a proof since the same result has been obtained, but for a mathematician that might not be enough, as the new frame work might still have other basic axioms that should be proven first as well. Derivation from other frameworks seems better language. It would certainly be alright to mention the derivation from the principle of unitarity of probabilities, as the lead should be a summary of the article. But I think the section in the body should also be presented in more accessible detail, in particular, why the 2nd law actually follows specifically.
@Michael C. Price:If you expand the unitary section, it is OK to mention that in the lead.--Netheril96 (talk) 00:48, 10 November 2010 (UTC)
Slightly expanded the unitary section. --Michael C. Price talk 21:20, 19 November 2010 (UTC)
Seems to me that a heavy dose of caution, and some industrial-strength caveats, are in order regarding "proofs" of the Second Law.
In particular, consider Loschmidt's paradox: if one could ever prove that entropy increased going forwards in time, if one applied the same mathematics starting from boundary conditions specified at a particular point in time but trying to retrodict into the past where the system came from, one would see entropy getting larger the further into the past one went.
There are also some questions to consider as to what assumptions are being made to allow entropy to change at all -- where is the mixing behaviour being considered to come from? If one could project forward from perfect information with perfect accuracy, there would be no mixing at all, and no entropy change, just determinism. Arguably, the entropy increase arises from coarse graining of states -- ie from a choice made by the analyst as to how to describe the system, and what information will be systematically thrown away.
For more detail, see the careful discussion of the H theorem and its meaning (or not) in the Tolman's classic book on Statistical Mechanics; its echo in Kittel [2]; also PCW Davies, p. 43 et seq [3]. Jheald (talk) 00:15, 20 November 2010 (UTC)
FWIW I go with your entropy increase arises from coarse graining of states -- ie from a choice made by the analyst as to how to describe the system, and what information will be systematically thrown away. At a fundamental level (i.e. no coarse graining) there is no entropy increase, which is the resolution to Loschmidt's paradox - no entropy increase in either temporal direction. But once we start restricting our interest to macrostates, then the entropy increase sneaks in. So where does this leave the article? --Michael C. Price talk 01:22, 20 November 2010 (UTC)
Michael C. Price - I've been reading Everett's thesis - I think that coarse graining is not the source of the increase of entropy over time. Coarse graining only adds a constant to the entropy. According to Everett - and I agree - from an information-theoretic point of view, looking at a classical situation, a microstate is a point in a 6N dimensional space. If you have a probability density in this space, then you can calculate a "total entropy" in the usual way. It can be proven by Liouville's theorem that this entropy remains constant in time. Its easier to talk of "information" defined as the negative of the "entropy". So it can be shown that Liouville's theorem implies that the information is constant in time. This information can be separated into a sum of "correlation information", which is information from knowing correlations among particle velocities, and "independent information", which is information available assuming no correlation exists. If, for example, you start out with a probability distribution in which each position and velocity of every particle is independent of any other (i.e. the probability density is a product of individual probabilities for each particle), then the information is pure "independent information". As time goes by, this information decreases while correlation information increases. The resolution to Loschmidt's paradox - no entropy increase. When you decide to renounce knowledge of correlations in position and momentum resulting from collisions (stosszahlansatz), you are left with the decreasing "independent information" or, equivalently, increasing "independent entropy" which is thermodynamic entropy divided by the Boltzmann constant, to within an additive constant. PAR (talk) 03:58, 27 April 2011 (UTC)

LaRouche[edit]

Perennial candidate for U.S. President Lyndon LaRouche has strong view on this topic:

  • Pobisk Kuznetsov.... and I agreed on many things, ... But, we disagreed on his defense of the so-called Second Law of Thermodynamics, which, for me, is bunk. [..] Now, the problem with this Second Law of Thermodynamics, is it's based on the assumption of a mathematical physics, not a physical chemistry. [..] In other words, that the Second Law of Thermodynamics is bunk: throw it away! [4]
  • The presumption concocted by such hoaxsters as Rudolf Clausius, Hermann Grassmann, Lord Kelvin, et al., which is known as the claimed principle of reductionist thermodynamics, the so-called principle of entropy (or, ‘second law’ of thermodynamics), was an ontological fraud from its inception. [5]
  • Among the most notable effects among what the work of Vernadsky has contributed to economic science, has been the crucial and systematic refutation of the hoax associated with the term "second law of thermodynamics." [6]

As these excerpts indicate, LaRouche views this so-called law with great skepticism, apparently believing in energy-flux density instead. Since LaRouche has followers, editors will occasionally drop in to add critical views.[7].   Will Beback  talk 

"apparently believing in energy-flux density instead." Obviously that is the case. You can take a bunch of mirrors and/or lenses to heat things above the temperature of the light source. It's just hard to engineer, but it is not impossible. Lenses and mirrors are obviously ways of increasing the "energy-flux density". It is also a way of sending heat energy from a colder object to a hotter object in an continuous and reliable manner. Such is impossible with systems relying only on conduction or convection however. The ability to concentrate heat this way must rely on the radiation form of heat that travels at the speed of light. As we know, light can be redirected at will using its properties of reflection and refraction. Also, recent attempts to treat the atom as a "hot" heat reservoir seem ad hoc and inappropriate to use for what is actually a quantum system whose ability to give off heat is selective in nature, and indeed, is the purview of quantum chemistry, not entropy.Kmarinas86 (Expert Sectioneer of Wikipedia) 19+9+14 + karma = 19+9+14 + talk = 86 14:04, 15 November 2010 (UTC)
Why are we discussing this? If it wasn't obvious before, it certainly is now - LaRouche is a crank, in thermodynamics as well as politics. --Michael C. Price talk 14:32, 15 November 2010 (UTC)
This was just meant as a "heads-up".   Will Beback  talk  19:41, 15 November 2010 (UTC)

Derivation from unitarity[edit]

An IP keeps reverting the derivation of the 2nd law in QM, claiming it is unsourced bullshit. I have expanded the reference to to make the sourcing more explicit. The quote in the reference now reads

Appendix I, pp 121 ff, in particular equation (4.4) at the top of page 127, and the statement on page 29 that "it is known that the [Shannon] entropy [...] is a monotone increasing function of the time."

Hopefully that is sufficient. -- cheers, Michael C. Price talk 10:44, 28 May 2011 (UTC)

The current text reads: "The time development operator in quantum theory is unitary, because the Hamiltonian is hermitian. Consequently the transition probability matrix is doubly stochastic, which implies the Second Law of Thermodynamics.[14][15] This derivation is quite general, based on the Shannon entropy, and does not require any assumptions beyond unitarity, which is universally accepted. It is a consequence of the irreversibility or singular nature of the general transition matrix."
I claim that this is both unresourced and BS. Specifically:
The first statement is correct. The first half of the second statement - "consequently the transition probability matrix is doubly stochastic" - is misleading, because in order to get the result the paper relies on the collapse postulate (to calculate the probabilities using the Born rule), which is itself not a consequence of the dynamics and is known to be in contradiction with it (aka the measurement problem - the many worlds interpretation, for which the quoted text is the locus classicus, is one of the attempts to get around this contradiction, but it is itself quite problematic). Hence it is not true that the derivation "does not require any assumptions beyond unitarity" (even if the unitary nature of the time development operator is used at one point). The last sentence - that the "singular nature of the general transition matrix" is responsible for the "derivation" is also completely opaque and if we take the standard meaning of "singular" matrix then is false. This whole section is misleading since it suggests that we are in a better position to "derive" the Second Law from QM (or QM+information theoretical approach to entropy) then in classical mechanics. We are not.
Regardless of the validity of the claims I contend that the quoted text itself does not make them. Sourcing is needed for:
  • the claim that unitarity is the only assumption needed to derive entropy increase
  • the claim that the doubly stochastic nature implies the Second Law of Thermodynamics.
Neither of these claims are made in the referenced text. In fact the text reiterates (on p 107) the by-then universally accepted claim that it is an "erroneous impression that the quantum formalism itself implies the existence of quantum-jumps (stochastic processes) independent of acts of observation." Without smuggling in collapse in one form or another the derivation can not be made. The way how the text smuggles in collapse is merely an interpretation of QM, there are other interpretations, like Bohmian mechanics, which do not rely on this assumption. This conjecture may have some value in the context of the Many World interpretation of QM but then it is needed to be appropriately sourced and merged under that heading. Inclusion under the Second Law article in this form is misleading. Cheers, Gyepi (talk) 14:38, 28 May 2011 (UTC)
It doesn't matter how the collapse (in one form or another) is smuggled in, the fact is that every interpretation smuggles it in one way or another, so this is not an interpretational issue - otherwise we would have the absurd situation where we could derive the 2nd law in some interpretation and not in others.
The derivation of double stochasticty from unitarity is trivial; tag that statement as requiring sourcing, if you must, but sources will be easy to find. -- cheers, Michael C. Price talk 17:05, 28 May 2011 (UTC)
This in untrue. Look up De Broglie–Bohm theory - there is absolutely no collapse in this interpretation (the theory is deterministic), and yet it is empirically equivalent with QM (or with Many Worlds interpretation). In that fraimwork this argumentation does not go through either. Again, a derivation which makes use of a contradiction which is then explained away by an interpretative move is not a derivation; it still faces the Lochsmidt's paradox.
Regardless of this debate (in which I'm trying to explain why the section is BS) I maintain that the section needs to be removed on grounds of not being sourced, or formulated in a way that is not misleading. Currently it is misleading and it is not sourced, there is no direct mentioning of these conclusions and their application to the Second Law even by the referenced author. I appeal to another editor to check the veracity of this claim. — Preceding unsigned comment added by Gyepi (talkcontribs) 17:33, 28 May 2011 (UTC)
Upon further reflection I might be wrong about the difference in derivability of the same statement between MW and Bohmian mechanics. I don't know how much does the derivation exploit the contradiction between dynamics and collapse, however I maintain that the interpretation of the results by the current wikipedia note is misleading even if this does not cause a problem. The reason is that the theorems referenced explicitely make use of the uniform measure. I.e. on page 29 referenced as the source by Michael C Price "This entropy is, however, simply the negative of the information relative to the uniform measure", Corollary 2 on p. 128 says that information relative to the uniform measure is decreasing in case of a doubly-stochastic matrix. Hence even if the derivation is not making use of a contradiction it is only valid given the fundamental postulate (=equal a priori probabilities). The current wikipedia entry juxtaposes the derivation in classical thermodynamics and statistical mechanics implying that in the second such postulate is not used. ("In classical thermodynamics, the second law is a basic postulate applicable to any system involving measurable heat transfer, while in statistical thermodynamics, the second law is a consequence of unitarity in quantum theory.") This is misleading and false.
Regardless of whether I'm identifying the source of the problem correctly I maintain that these statements can not be found in the original text. Given that they would be fairly important if they were true one would assume that they appear somewhere in the physics literature between 1956 and 2011 so finding another source should not be a problem. I wouldn't have high hopes for this; for instance many experts read Everett's thesis (since as I mentioned it is the locus classicus of MW interpretation), yet this achievement of Everett somehow seems to have skipped the attention of all these scholars since it is not even gestured at in articles written by experts (ie http://plato.stanford.edu/entries/qm-everett/ ). — Preceding unsigned comment added by Gyepi (talkcontribs) 18:55, 28 May 2011 (UTC)
I don't know whether the second law follows from unitary evolution or not. I do know that Loschmidt's paradox and classical statistical mechanics do not need quantum mechanics for their resolution, and I expect their resolution in QM is analogous. Not knowing enough about this, I would hope that this article will inform me of any controversy about this and provide me with enough references to allow me to investigate the controversy. I would hope that the article does not provide one single point of view because one school or the other "won" the argument. PAR (talk) 20:21, 28 May 2011 (UTC)
I agree here. Forgetting about Everett and Many Worlds specifically, just using common sense, you can see that the psysical state of a sysem has to contain correlations of a conspirational nature, otherwise the entropy cannot become smaller when evolving the system back in time. But these correlations can apparently be ignored when evolving the system forward in time. It is perhaps more interesting to include some modern treatments that consider the case of isolated systems. I have seen some articles were random matrix theory is invoked to derive thermodynamics (instead of ergodicity, which is typically irrelevant realistic situations). Count Iblis (talk) 20:49, 28 May 2011 (UTC)
Iblis, you can't evolve the system back in time with a non-invertible transition matrix. -- cheers, Michael C. Price talk 22:27, 28 May 2011 (UTC)
I see, but then the validity of invoking those transition matrices is an assumption that is not purely implied by unitarity alone. Count Iblis (talk) 00:03, 29 May 2011 (UTC)
There is no "resolution" of Loschmidt's paradox, classical or quantum, which would be widely accepted in the literature as such. There are resolution attempts, such as relying on the past hypothesis, which are seriously criticised. It is me who defends the generally accepted position here, namely that we don't have yet a non-postulate based derivation of the Second Law from either classical or quantum dynamics. (For the state of literature on these issues see e.g. http://plato.stanford.edu/entries/time-thermo or http://plato.stanford.edu/entries/statphys-statmech .) It is fine to mention a controversy in the literature, but this is not what the current page does, the current page makes it seem this is a settled issue, and does so by making claims which are not sourced (by making claims which are not made by the referred text, but which are interpretations of a wikipedia contributor). I don't know what is not clear about this point I'm making. The current text either needs to be changed significantly, or sourced appropriately, or removed. Gyepi (talk) 21:01, 28 May 2011 (UTC)
I don't know what is not clear about this point I'm making. What is clear is that you haven't understood a lot of your claims.
  1. You either don't understand DeBroglie-Bohm or see the significance of my rider about collapse "in some form or another". However this is all irrelevant; Everett's derivation of the 2nd law preceeds, and is independent of, his interpretational construction.
  2. You claim that Everett relies on assuming equal a priori probabilities; you have confused his "uniform measure" with the a priori probabilities; there is no connection.
  3. You have failed to explain why the quote "it is known that the [Shannon] entropy [...] is a monotone increasing function of the time." is not explicit enough.
-- cheers, Michael C. Price talk 22:27, 28 May 2011 (UTC)

Clausius-Mussoti etc.[edit]

To To 59.177.108.25 aka 120.56.176.59:

I think you are confusing the Clausius statement of the second law with the Clausius–Mossotti relation, which has to do with dielectrics. Please provide a reference if I am wrong, and check the spelling of the second name. Also, the Kelvin statement might be properly referred to as the Kelvin-Planck statement, I don't know. At any rate, your spelling of Planck is also incorrect. PAR (talk) 15:44, 7 October 2011 (UTC)

Lead really needs to be simplified[edit]

The lead is extremely dense. As a non-scientist, I came to this page for a quick refresher of what the 2nd Law states. Instead, I had to sift though some fairly obtuse text to realize the simple answer I was looking for is it's about entropy. I am sure the information provided is more precise, and would be more useful to people in certain situations. But, for the average reader, would it be correct to say something along the lines of "The 2nd law generally states that, in a closed system, entropy tends to increase"? I acknowledge this involves a weasel word (i.e. generally states) but it's much easier to digest. And, if someone wanted more info, they could still find the additional specifics within the body of the article.

I should note again that I am not a scientist and haven't studied this since high school -- it's entirely possible my proposed definition is not entirely correct. But, perhaps we could modify it to make sure it's accurate, and yet still easy to understand. Thoughts? JoelWhy? talk 13:34, 6 June 2012 (UTC)

Agreed. The lead is awful. Even if you understand physics, its still a headache to read. For example instead of "The second law declares the impossibility of machines that generate usable energy from the abundant internal energy of nature by processes called perpetual motion of the second kind", we could just say ""The second law declares that perpetual motion machines are impossible". Kaldari (talk) 23:44, 5 July 2012 (UTC)

I modified lead section accordingly. Dan Gluck (talk) 21:47, 15 February 2013 (UTC)

"Accordingly" is not accurate. The 'modification' was not a simplification. It was a re-casting from a particular point of view.Chjoaygame (talk) 01:28, 17 February 2013 (UTC)

William Sidis's speculation is not mentioned[edit]

How come William Sidis's mental experiment,the one that comes to the conclusion that there are ( might be) regions in the universe where the second law of thermodynamics operates in reverse, is not mentioned? I could not find any article that refutes his claim. To be fair i have not found anything that might validate the conclusion either. Still it probably should be mentioned in the article even though his speculations have not been verified to this date ( from what i know...). — Preceding unsigned comment added by Olajon (talkcontribs) 11:25, 6 July 2012 (UTC)

Is there a reference (preferably online) that clearly explains his reasoning? PAR (talk) 12:28, 6 July 2012 (UTC)
http://www.sidis.net/ANIMContents.htm . Somewhere in chapter 4 he reaches a first conclusion regarding the 2LoT. Well, if by "reference" you mean a reputable 3rd party source,no. But Buckminster Fuller " (upon receiving a copy of The Animate and the Inanimate 65 years later, expressed in a letter to Scientific American his "...excitement and joy that Sidis did go on to fulfill his promise.") " and that is a good indicator that WJS's reasoning which is probably based on theories, postulates and observations of the time ( including theory of relativity and quantum mechanics which where available in 1920 when he finished the book and in 1925 when he decided to publish it) isn't all mumbo-jumbo and might deserve to be mentioned in the article. Hopefully some physicists ( astrophysicists actually) might further clarify whether there any observations that contradict his claims from the first half of the book. Olajon (talk) 19:52, 7 July 2012 (UTC)
I've looked at the reference, and it appears to me that he does not speak the language of statistical mechanics except in a very vague way. For example:

"Tracing thus from a given momentary condition of the universe, our forward and backward reasoning combined might be interpreted, if such reasoning could be trusted, to mean that the second law of thermodynamics holds good as a probability as to the future, but that its reversal holds true as to the past. Aside from this result being untrue in point of fact, it is self-contradictory, for any given moment of time is always future as to moments that precede it, and past as to moments that follow it. It follows, then, that there must be some fallacy in Clerk-Maxwell's reasoning, which, when extended, gives us the second law of thermodynamics in the general form."

This is, to me, an impenetrably vague statement. The article is basically in the same vein, without any mathematical development. I think, in order for this theory to be taken seriously, it has to have some discussion and support by peer-reviewed third parties. PAR (talk) 16:07, 8 July 2012 (UTC)
Mathematical development would probably make the book much larger. I agree that the particular paragraph you quote is kind of vague ( to me) but I thought it was just because i'm not a native speaker of english and i don't understand some of the constructs he uses. I also see that loschmidt also imagined and pointed the weirdness of the 2LoT when time is reversed before Sidis.

it has to have some discussion and support by peer-reviewed third parties

True but i think most are avoiding the book probably because of it's second part which discusess life and other topics.
The part in the book where the 2LoT is suggested to be an overwhelming probability rather than a law is also confirmed in the fluctuation theorem ( from what i understand)
What's left is the claim that there are regions where the 2LoT is reversed which has not been discussed by reputable sources.( As i said before,I sometimes feel this book is not viewed seriously because of the second part, not because of the lack of math development).I'm a little busy right now but once my workload gets lighter i will see at least what the physics-forums people think about this and maybe send some emails to some random picked universities's science departments.That hopefully will spur an interesting discussion.Or maybe some angry replies :)
In the end i still believe it would deserve a honorable mention maybe in a new chapter called Unproved claims pertaining to 2LoT if not in the controversies section .But maybe that is too much, as you say. Olajon (talk) 05:44, 10 July 2012 (UTC)
It looks that at very small scale the probabilities of 2LoT are a little different, since there are intervals smaller than 2 seconds when the 2LoT is not respected overall. http://www.newscientist.com/article/dn2572-second-law-of-thermodynamics-broken.html Olajon (talk) 06:03, 10 July 2012 (UTC)
The idea that the second law can be "broken" is not news. Even Boltzmann, the guy who developed the statistical mechanics description of the second law, knew it could be "broken". And using the word "broken" is arguable. You could say that the second law only strictly holds in thermodynamic limit - the limit of an infinite number of particles, and the fluctuation theorem describes the probabilies that a finite system will deviate from the predictions of the second law. The smaller the system, the larger the expected amount of deviation. You could say the second law is never broken, because there is no real system that it applies to, its a limiting case that never happens in the real world, and its value lies in the fact that larger systems obey it more closely than small systems. But there's more drama in setting up the second law as a straw man by pretending it applies to all systems, and then knocking down the straw man with "fascinating" experiments that prove that it is violated.
I cannot imagine a case where the second law is reversed. The statistical mechanics explanation of the second law is based on the idea that all possible microscopic configurations of a system are equally likely to occur over an infinite amount of time, and that most of the macroscopic states of a system are indistinguishible from each other. It follows that a macroscopically unlikely state (low entropy) will most probably evolve towards a macroscopically likely state (high entropy). If the second law is to be reversed, then one of these assumptions has to be suspended. Sidis' musings never delve this deep into the foundations of the second law, so I am really doubtful of the validity of his reasoning. PAR (talk) 02:47, 11 July 2012 (UTC)

My ha'penny worth[edit]

"...natural processes have a preferred direction of progress..." should be re-phrased without using the concept of preference. It is absurd to suggest that natural processes 'prefer' anything. Please try to work out exactly what you mean, and express it clearly. Perhaps 'spontaneous' might be what you have in mind ?

"This also means that it is impossible to build solar panels that generate electricity solely from the infrared band of the electromagnetic spectrum without consideration of the temperature on the other side of the panel (as is the case with conventional solar panels that operate in the visible spectrum)." It is not impossible in principle that photovoltaic cells working on the energy-gap principle could be made to work in the infra-red region. In fact, given the properties of silicon as a semiconductor one can predict that conventional photocells do in fact operate in the infrared. The point which should be made here is not the difference in wavelength involved, but alternative thermodynamic principles, namely the random nature of heat, and the 'ordered' nature of e-m radiation as energy forms. Replacing "the infrared band of the electromagnetic spectrum" by "heat" would be a gesture in the right direction. Conversion of e-m radiant energy to other forms is theoretically possible with 100% efficiency just as the conversion of mechanical energy is; this happens in wireless aerials. But the conversion of thermal energy to other forms is subject to the implications of the 2nd law, Carnot's law, etc; it is in fact the basic problem of thermodynamics. Perhaps rather than obscuring this important basic idea it might be worth elaborating it, and trying to say what it is about thermal energy which distinguishes it from other forms in this respect. This, it seems to me, is the key concept involved in the 2nd law, and in fact is what it is all about; it should at least be mentioned, preferably at the top of the page.

Work Gain[edit]

It has been shown that the second law of thermodynamics can be violated using entanglement, unless this paper is refuted or I am misunderstanding the paper and the news articles that referenced it. http://arxiv.org/pdf/1207.6872v1.pdf — Preceding unsigned comment added by 70.249.57.112 (talk) 21:49, 17 October 2012 (UTC)

The paper doesn't claim to violate the second law. It claims:

We have extended the second law of thermodynamics with feedback control to the case of ini- tially entangled states. We have shown that work can be extracted beyond classical correlation from entangle- ment. — Preceding unsigned comment added by MorphismOfDoom (talkcontribs) 19:23, 5 June 2013 (UTC)

Carathéodory statement[edit]

Is the Carathéodory statement different from a careful topological/differential-geometric statement (for a suitable manifold of states of thermodynamic equilibrium) that has the physical meaning just that temperature belongs to a 1-manifold, and that transfer of energy as heat is one-way, from hot to cold?Chjoaygame (talk) 07:19, 24 January 2013 (UTC)

recent raft of edits[edit]

The recent raft of edits was researched and sourced and well-intentioned, but was too much an expression of the editor's private thinking and speculation, verging on drivel at times.Chjoaygame (talk) 01:27, 17 February 2013 (UTC)

Can you please elaborate on this? it is widely accepted among particle physicists that the second law is a consequence of the initial conditions of the universe. What the H-theorem proves is that given that a system in time t1 is far from equilibrium, there is a high probability that in another time t2 it is closer to equilibrium; but in fact t2 can be either larger or smaller than t1. Therefore in order to prove the second law the H-theorem must be accompanied with the assumption of low-entropy initial conditions. Dan Gluck (talk) 20:54, 20 February 2013 (UTC)

In all, what you have done is deleting well-resourced (and well-intended, as you admit) material with no explanation. This is not in accord with WP policy. Please explain - or, even better, discuss the issue - before you revert. Specifically, where did I express my personal (hence, unsourced) opinion, and where did I go pseudo-scientifically?Dan Gluck (talk) 21:50, 20 February 2013 (UTC)

It is wrong to say that the second law is "derived" from the big bang, or that it is "derived" from statistical mechanics. The second law is a concise statement empirical fact. It is derived from an enormous body of experimental data. This is what makes it a "law". Maxwell's equations of electrodynamics are, likewise, a "law", a statement of empirical fact. If any valid experimental data were to be generated that disagreed with the law, it would be a law no more. Statistical mechanics makes a series of assumptions, and explains the second law, but it does not logically supercede the second law. If statistical mechanics makes a statement in conflict with the second law, then statistical mechanics is wrong, not the second law. The second law is likewise not "derived" from the big bang. It is derived from experimental data. The question of what the second law implies regarding the origin of the universe is a subject that is outside of the second law and should be thoroughly discussed in an article on cosmology. Mention of this should be made in this article, with appropriate links to an article on cosmology, but to imply that the second law "derives" from the big bang is wrong, and it should not appear here and there in this article. PAR (talk) 22:48, 20 February 2013 (UTC)
I do not wish to spend time on this, so I will not go into detail. I think the above remarks by PAR are sound and reliable. Dan Gluck proposes above that "it is widely accepted amongst particle physicists that the second law is a consequence of the initial conditions of the universe". I don't know what particle physicists widely accept, but if they accepted that, they would be mistaken. I continue to think that the recent raft of edits drifts into speculation, opinion, and even worse, which I will not name unless it becomes necessary.
That material is sourced does not ensure that it is reliably sourced. In scientific matters of this level of subtlety and complexity, reliable sourcing often requires a concordance of several well-established sources assessed by a person, or even by a consensus of persons, who are more or less expert in the subject. With all respect, I am not happy that what sourcing there is of the recent raft of edits has been adequately assessed. I repeat that I think the above remarks by PAR are sound and reliable.Chjoaygame (talk) 01:22, 21 February 2013 (UTC)

Yeah, well I agree with PAR on the philosophical level - though this has nothing to do with my recent edits - except that I would replace the word "derived" in his writing with the word "proven". Thus, it is wrong to say "the second law is proven by such-and-such theoretical considerations", and it would be better to state "the second law is confirmed by experiments, and can be mathematically derived by such-and-such, which strengthen the validity of this theory". However, this is not an article about philosophy of science. Indeed, the word "proved" should probably be changed to "can be derived" - where "derive" here means mathematical derivation. Regarding what Chjoaygame wrote - I agree that one can often find sources for rubbish. However, this seldom happens with a source like Hawking, one of the leading figures in the modern understanding of thermodynamics. If you have any reservations, it may be interesting to hear them, but you cannot change a well-sourced (in fact, extremely well sourced) argument based on your personal preferences or opinions. It could be, of course, that Hawking, Beckenstein, Green and most other high-energy physicists are wrong, but you need more than such an assertion to make an edit here. In any case, you still have not made a single factual claim.Dan Gluck (talk) 14:55, 21 February 2013 (UTC)

This is a specialized topic on which I am far from expert. I think that the sentence in the current version of the lead, "The second law is thought to be the source of the direction of time", is not duly supported in the body of the article, and therefore has no place in the lead at present. I also think it is nonsense, but not being an expert I cannot support that in detail. I am aware that it has often been said in the literature, by experts indeed. But I am not impressed that Stephen Hawking or any specialist of his kind might be able to provide other than unprovable speculation as support for the sentence. Such a broad claim needs support from a wider base than such specialists, no matter how thunderous their reputations. I also think that talk in the lead of "low-entropy initial conditions in the beginning of the universe" is verging on pseudo-science. Again I am no expert, and cannot support my thoughts in detail. But I think that the initial conditions of the universe are a matter for cosmology, and have little place in the present article. I can understand that cosmologists might think their subject and its conclusions are more important and reliable, for this article, than I do. You may feel that I did not have enough support to justify my initial undoing of your edit, and perhaps you may be right about that. My defence is that your edit was radical, and that it seemed to me to be over-speculative and to call on ideas not immediately the subject of the present article, and that no one else had objected to it; but it needed some more thought before it could be allowed to stand and wait for a fortunate accident of someone with the necessary time and energy and expertise finding it and criticizing it properly. My reason is therefore 'better criticize now and be mistaken, than not criticize now and let nonsense stand'.Chjoaygame (talk) 19:03, 21 February 2013 (UTC)
That's OK, I understand your caution. In the future please try to read the sourced material, at least a bit of it, in order to avoid deleting good edits. Otherwise you might deter less experienced wikipedians, including those who are themselves experts in the field they are writing about.
As for the subject matter, the relation between the second law and the arrow of time is no more pseudo-science than the theory of relativity is. Sometimes physics just has deep things to say about reality. However your remark that the lead cannot include stuff that doesn't appear in the article is correct, and I have added a small section about the subject. It is just too important to be left out, since this one of the main reasons for the important place of the second law in physics.
Regarding your suspicion of cosmologists, that's well understood, but actually high energy physics is not cosmology. It deals with particle physics, quantum field theory and general relativity, and in general with the fundemental laws of physics. In this framework the first law of thermodynamics (conservation of energy) is derived from more basic principles (to go technically, the energy is the Noether current of translation in the time direction, and is therefore conserved); likewise, the second law is also dealt with within this framework. Therefore this community is exactly where the expertise regarding the origins of the second law lies. Dan Gluck (talk) 22:07, 21 February 2013 (UTC)
  • I am not suggesting one bit that the relation between the arrow of time and the second law is pseudo-science, but the big bang theory is not the main reason for the importance of the second law. I am not suspicious of cosmologists, they do hard science, but, due to the fact that they cannot observe their systems of interest in the way that thermodynamicists can observe theirs here on earth, and the range of phenomena of interest are much greater than here on earth, they have not been able to come up with a theory of the universe that is as solid as the laws of thermodynamics. The big bang is not an established fact. We could be living in an infinite universe, in which case fluctuation theory predicts that there is no upper limit on the size of a local fluctuation. Our observed universe could be a random local entropy drop in an infinite universe. All we know for sure is that entropy is low, and getting higher everywhere we look. The second law states this quantitatively. End of story.
The fundamental point of the first law is the existence of an internal energy as a state function and the existence of heat(ing) as a method of energy transfer, besides the macroscopic work terms. The first law cannot be derived from conservation of the Noether current of translation in time, unless you introduce the assumptions of statistical mechanics. Assumptions which do not need to be made in order to state or verify the first law. The second law is even more certainly not "dealt with within this framework". Cosmologists must certainly understand the laws of thermodynamics, and, since they are dealing with a wide range of phenomena, are possibly more liable to detect violations of these laws. But when you talk about the "origins" of the second law, this is disturbing. I assume you mean a study of the reason for low entropy to begin with. The second law makes no statement about the origin of low entropy, it simply maps out how things develop given the assumption of low entropy. In that sense, cosmologists have no more claim to expertise about the second law than any other discipline that uses it. They do have claim to understanding the origin of low entropy but then, this is not the province of the second law. PAR (talk) 05:45, 22 February 2013 (UTC)
  • I just dropped a pencil and it fell to the floor. This had nothing to do with the second law of thermodynamics. The microscopic explanation of the second law is in terms of combinatorics, not of quantum field theory. I see Dan Gluck has the bit between his teeth and I do not have time to try further to hold him back.Chjoaygame (talk) 06:38, 22 February 2013 (UTC)
A real expert in this area is Walter T. Grandy. On page 151, he writes: "Pondering the mystery of time asymmetry is indeed a worthy pursuit, but we find it quite difficult to relate this apparent feature of the universe to our local observations of irreversibility. It is rather presumptuous to speak of the entropy of a universe about which we still understand so little, and we wonder how one might define thermodynamic entropy for a universe and its major constituents that have never been in equilibrium in their entire existence. Is the Big Bang a reproducible process? On a more prosaic level, we have no idea how to envision, let alone calculate, the entropy of a worm! For these reasons we decline to speculate here on the relation of entropy to the long-term fate of the universe and whether or not it will run down and burn out." (Entropy and the Time Evolution of Macroscopic Systems, (2008) Oxford University Press, Oxford, ISBN 978-0-19-954617-6.)Chjoaygame (talk) 06:54, 22 February 2013 (UTC)
Par and Chjoaygame - I suggest you read pages 35-36 of the following article by Joel Lebowitz, the editor-in-chief of the journal of statistical physics, which also cites Boltzmann - you can't get more expert than this: [8]. In fact I will add this as a reference to the second law article here. According to google scholar Lebowitz's article is cited 233 times, more than any of Grandy's books - though the latter have a much greater scope.
Par's and Grandy's arguments are quite similar. It is an argument about the epistemological status of the second law, compared to the big bang thoery: the second law has been verified to a much greater extent than the big bang theory. This is true, but it does not mean that the big bang cannot be the reason for the second law. The issue is similar to the following: the fact that apples fall from trees is verified to a much greater extent than Newton's law of gravity. We are much more sure that apples fall from trees, than we are about Newton's laws. But still, we say that the fall of an apple is a consequence of Newton's laws. Thus, a reason can have a lower epistemological status than its effect. And while this subject is interesting, it is obviously not relevant to the article about the second law, but rather to an article about epistemology or the philosophy of science.
Finally, Chjoaygame - surprising as it may sound, the fact that pencils can fall from your hand but not rise up from the floor spontaneously to your hand is, in fact, a consequence of the second law. When a pencil falls off from your hand and hits the floor, its kinetic energy is dissipated by forming sound waves (i.e. phonons) in the floor's matter. These propagate seemingly randomly and thus turn to heat (Note that they are only apparently random because they are in fact correlated, as they all originate from a single event - the hit of the pencil in the floor). The opposite event - where sound waves in the floor arrive from all directions and at the same moment hit a pencil lying on the floor and cause it to hop in the air right into your hand - is perfectly possible by all physical laws, except for the second law: such an event leads to a decrease in the entorpy and therefore violates the second law.
Microscopally speaking, unless we prepare the sound waves in advance, such an event has an extremely low probability. But the way we choose to calculate probabilities relies on different assumptions about the initial and the final conditions of the system, and eventually assume that we start with low entropy conditions. I can elaborate more on this if you like. Dan Gluck (talk) 12:21, 22 February 2013 (UTC)
Dan Gluck, I am flattered that you care enough to try to change my mind, but I can only repeat that I see you have the bit between your teeth and that I do not have time to try further to hold you back.Chjoaygame (talk) 15:05, 22 February 2013 (UTC)

While I haven't looked in detail at the disputed edits, I agree with the basic point that Dan Gluck is making here. This article actually does mention the issues regarding time symmetry and irriversibility at the macro level, so I don't see why this can't be explained better and from the point of view of modern physics. Given what we do know and what is thought to be well established (and that's obviously not everything), the initial conditions are of crucial importance for the second law. Time reversibility (or more precisely the fact that by the CPT theorem, the time reversed system behaves in the same way as the original system as far as information/entropy is concerned) simply cannot be ignored...

Another thing is that we need to put in the missing small print in the derivation by Everett based on MWI. As this stands it looks like no non-trivial assumptions are made, but it are precisely these hidden assumptions that make it work. Count Iblis (talk) 12:43, 22 February 2013 (UTC)

I agree completely, time reversal assymetry and irreversibility is fundamental to understanding entropy and the second law, and more emphasis should be placed on it. It is the only really intuitive link that everyone, non-physicists included, have to understanding entropy. The point I was trying to make to Dan Gluck is that the origin of the less-than-maximum entropy universe that we live in is not addressed by the second law. It basically says that, given less-than-maximum entropy, entropy will increase. That's all. The question of the direction of the "arrow of time" is very much part of an understanding of the second law, but "where does the arrow begin?" is not. That's a subject for cosmology, and the expertise and range of physical principles needed to approach this subject goes way beyond the second law, covering practically all of physics as we know it now. The second law alone does not imply the big bang theory. The only advantage that cosmologists have in understanding and interpreting the second law is that they apply the second law to a much wider range of phenomena. This does not make them more expert on the understanding and interpretation of the second law unless they find a violation, and, to my knowledge, they have not. PAR (talk) 17:15, 22 February 2013 (UTC)
PAR, I agree with you completely, except for one sentence: you write 'The question of the direction of the "arrow of time" is very much part of an understanding of the second law, but "where does the arrow begin?" is not.'
In my opinion, It is a part of the understanding of the second law because it's supposed to be the reason for it.
You write "the origin of the less-than-maximum entropy universe that we live in is not addressed by the second law" - that's true. But again, this origin is the reason for the second law (at least theoretically), so we should mention it.
You are right that it could have been that the origin is a fluctuation in entropy rather than a low entropy in the beginning in the universe, there's a famous paradox about it, but it's a paradox because it destroys virtually all possibility of reasoning about the past. You are welcome to write about that in this article. But as for now, as long as we don't go into this subtlety, the reference to cosmology is just fine - it both avoids this complication and is correct (since it seems that cosmologists do find evidence for very low entropy in the past, namely the isotropy of the CMB). If you have a better suggestion, please bring it up.
Now for a little discussion of that paradox. If we take initial conditions of the universe to be at low entropy, there is no problem. But if we take high-entropy initial conditions, then it is highly unlikely to get a low-entropy fluctuation later. Thus just taking low-entropy initial conditions (i.e. in the big bang) is probably a better approach.
Regarding experts, I didn't bring Hawking as an expert because he is a cosmologist (in fact, he is not - he is an expert in general relativity), but rather because his work together with Beckenstein's on the thermodynamics of black holes is one of the most important works (or maybe just one important work) in relation to the theoretical foundations of thermodynamics. Anyway, Lebowitz is an expert on statistical mechanics, and he also points to the origin of the secnd law as a cosmological question. Dan Gluck (talk) 10:08, 23 February 2013 (UTC)
Well, then, we agree more than I thought. I also think mention should be made of the cause of the low entropy universe, but I still don't see that as fundamental to understanding the second law any more than understanding an electron is fundamental to understanding Maxwell's equations. I also disagree about your statement that "if we take high-entropy initial conditions, then it is highly unlikely to get a low-entropy fluctuation later. Thus just taking low-entropy initial conditions (i.e. in the big bang) is probably a better approach." The probability of a fluctuation of a given size increases with the amount of time you wait and with the size of the system. As the size or the time approaches infinity, the probability approaches unity. If I have liter container of gas, I can calculate the average amount of time that must pass before every one of the gas molecules in that container are located on the left half of the container, and that time is not zero. It's staggeringly large, but if you have an infinite amount of time, then it will certainly happen. If I have a large volume, I can calculate the probability that, in the next second, a liter-sized volume element will have all its molecules packed into its left half. That's a very low entropy volume element. The larger my volume, the higher the probability is that I will find one in the next second, even though that probability is staggeringly small for terrestrial-size volumes. I can calculate the average size of my large volume that would be needed to find such a low-entropy volume element in the next second, and its a finite number. If I have an infinite volume, then such a low-entropy volume element will certainly appear somewhere in the next second of time. In fact, an infinite number of such low-entropy volume elements will occur. I can calculate the average size of a volume needed to find an observable-universe-sized fluctuation with the entropy on the order of our own observable universe in the next second and that size will not be infinite. If I have an infinite volume, then such a low-entropy universe will certainly appear somewhere in the next second of time. In fact, an infinite number of such low-entropy universes will occur.
I'm not a cosmologist, so there may be reasons that these considerations cannot possibly hold in our universe. But then, I have a fair understanding of the second law, and I am quite sure that the second law will NOT be the reason that these considerations cannot hold. In other words, you have to bring in other considerations to prove that the above scenario cannot hold, which proves my point: You cannot use the second law (the direction of the arrow) alone to find the source of initial low entropy (the source of the arrow). You don't need to know the source of the arrow in order to understand its direction and a statement of its direction tells you little about its source. PAR (talk) 14:05, 23 February 2013 (UTC)
I see your point. This is in fact the Boltzmann brain idea/paradox. On the one hand, it is not so far from modern ideas about the multiverse combined with the anthropic principle; on the pther hand, these relate not to some point after the big bang but rather to how the big bang itself came about in a low-entropy state. The problems with assuming a later fluctuation scenario come both from the paradox that we get, and from the evidence for low entropy in the very early universe (mainly CMB isotropy, and possibly also the success of the nucleosynthesis calculations). But you are right that these are beyond the scope of this article.
I will try to make few changes to reflect this. Something like writing "the very early universe" instead of "the beginning of the universe" (though I'll put back the link to the big bang, since a link to "cosmology" is too vague; additionally, the big bang sometimes refer to the whole period until the formation of the CMB, for which there is already good evidence for low entropy); and will add a link to the Boltzmann brain article.Dan Gluck (talk) 23:03, 23 February 2013 (UTC)
I've made the changes, seems to me better now. Dan Gluck (talk) 23:13, 23 February 2013 (UTC)

repeated citation; query self-promotion[edit]

An edit has been posted which repeats reference. I have tidied this up.

Not an expert in this area, still I get the feeling that this section should have given significant explicit note to Einstein's fluctuation formula. Absence of this seems a serious weakness in the section.

This edit seems to draw attention to the possibility that its parent paragraph looks suspiciously like self-promotion. I am no Wikilawyer, and I do not know how to check on such a suspicion. Perhaps someone who knows more about it can comment?Chjoaygame (talk) 23:47, 20 March 2013 (UTC)


a more general doubt about readability[edit]

There seems to be a tendency to what I want to call "nerd talk" on subjects like this. After reading the entire article (not the formulas!) I finally decided to look on the Simple English Wikipedia and found exactly what I needed. (As if to confirm the tendency, that article has a note on it that it should be simplified.) And I'm sure that only a very rare reader would be wanting this article here to be as technical as it is. In other words: I think the Simple English article would do very well as the main article on the second law of thermodynamics here on the English Wikipedia, with a link to a sister article called something like "Second law of thermodynamics (scientific)" containing the current article's text.

Actually, a more fundamental problem is lurking here: Scientific stuff can't be described in simple language without losing accuracy, so authors really knowing the subject are generally unable to write such simpler descriptions. One "solution" could be to include a "non-accuracy clause" in such articles somewhat like the caution clause in medical ones, although I confess I'm smiling at the idea. With such a clause in place, authors may feel easier about giving up some correctness and thus be better dispositioned to write a readable text.

If you know a good place to raise this (second) point, please let me know. Geke (talk) 11:36, 4 April 2013 (UTC)

I don't think there is a problem with this article being technical or being too nerdy, the problem as I see it is that it doesn't cater to the casual reader. It should really try to do both. In particular, the second law of thermodynamics has a special place in popular culture (the popular concept of disorder), yet there is no acknowledgement of this, or any explanation or discussion that could shed light on the popular concept. As such, the article isn't of much use to the casual reader. Hzh (talk) 23:56, 11 May 2013 (UTC)

Actually it is more than the "casual reader" that is left behind. The style of this article, notably including omission of dependent variables, makes this only readable to the already informed.

reason for deletion of new section[edit]

I have noted that the new section, now deleted by me, was covered by a note asking for its retention if the only objection to it was that it was currently not well written.

I have deleted it because of objection to its intellectual content and because of its inadequate sourcing.

I could expand very much on these reasons, but probably my expansions would provoke a superfluous response, unless my expansions were exceptionally well written.

Therefore I will be very brief. Thermodynamics is very well understood for homogeneous bodies, constituted of materials that reach their own internal thermodynamic equilibrium quickly on time scales short in comparison with the time scales of processes contemplated for them, in which there is no internal flow; that is classical equilibrium thermodynamics. For other systems, as those provisos weaken, thermodynamics is less well understood. For systems very far from thermodynamic equilibrium, thermodynamics is practically a pipe-dream rather than a well understood science. According to Grandy, W.T., Jr (2008), Entropy and the Time Evolution of Macroscopic Systems, Oxford University Press, Oxford UK, ISBN978-0-19-954617-6, on page 151: "... we have no idea how to envisage, let alone calculate, the entropy of a worm!" There is a literature on non-equilibrium thermodynamics, which purports to explain the emergence of order, and is worth reading, and which might perhaps be regarded as providing reliable sourcing for some of the statements in the new section, but is not cited in it; the new and now deleted section was inadequately sourced. It looks as if it was not even adequately thought out from this less speculative viewpoint.

The present article has regrettably already overstepped the bounds of well understood physics, but the new and now deleted section, if left standing, would have been an open invitation to extend the article into more unfounded and pseudo-scientific speculation and worse. The article at present mostly pretends to be scientific. If a speculative article is desired along the lines of the new and now deleted section, perhaps a new article without scientific pretensions would be considered.Chjoaygame (talk) 22:44, 23 April 2013 (UTC)

An encyclopedia documents facts, not truth. Narssarssuaq (talk) 12:21, 27 April 2013 (UTC)

a "more recent statement"[edit]

The recently added "more recent statement" has perhaps some problems.

It is not altogether clear that it is not some kind of self-or-related-party promotion. There are in the literature probably hundreds of more recent statements of the law, and no reason is cited for selecting from amongst them the one actually chosen here. In contrast, the other statements cited in the article are celebrated ones with widely recognized historical importance. The "more recent statement" is placed with special emphasis or prominence, not in the list of historically recognized statements, but in the preamble to that list, as if the "more recent statement" was somehow better or preferable or otherwise more important.

The term "reversible weight process" is a slightly idiosyncratic usage of language. Yes, it makes sense, and is physically valid, but it is not a regular part of the ordinary usage and is not defined here.

The term "state" is used in a slightly idiosyncratic way by the "more recent state". A thermodynamic state is usually taken as being a state of internal thermodynamic equilibrium. The term "state" here intends that the system in general not be in a state of internal thermodynamic equilibrium. Moreover, it seems that the initial "state" of the system, as intended by the "more recent statement" needs a process of externally driven work to bring it to its eventual internal state of thermodynamic equilibrium. It seems odd that externally driven work is needed, when one might expect that the state of internal thermodynamic equilibrium will be reached eventually simply by internal evolution without externally driven work. These points are not explained in the article as it stands.

Combining these reasons, I am unhappy with the recently added "more recent statement".Chjoaygame (talk) 21:48, 1 June 2013 (UTC)

pseudo-science[edit]

Editor Dan Gluck, your edit has a cover note that tries to make out that we are looking here at a point of view issue. No, this is about precise thinking in a scientific article. Clausius and Kelvin were being expansive and rhetorical. Their expansive ideas on this subject are not adequate science today, and Wikipedia should not suggest to the contrary. It is bad enough that the article Heat death of the universe tries to suggest to the contrary, but that pseudo-scientific contagion should not spread to here. To appear 'neutral' about this is to support pseudo-science.Chjoaygame (talk) 22:40, 30 July 2013 (UTC)

Dear Chjoaygame, first I want to thank you for keeping this article in a high level and clean of nonsense like that fringe material you just deleted few days ago (the "contra-something law", I don't really remember). Regarding the subject at hand, the naive heat-death scenario is simply an old scientific theory, which has been replaced, but this is surely not pseudo-science. Therefore, I see no point in giving it a whole section. However It is, in fact, not very far from the current view of matters, so I changed the section name to something like "future of the universe" and wrote the current understanding of things, based on a very highly-cited article (187 according to google). Additionaly, I saw another problem with the former version: it looked more like wikiquote than wikipedia. A scientific article should not give such long quotes, just state the facts (or opinions if facts are not available or have many interpretations) and cite. Dan Gluck (talk) 20:42, 1 August 2013 (UTC)
Thank you Dan Gluck. Yes, perhaps I put it a bit hard calling it pseudo. It's old, as you say. I wrote the full quotes because I wanted editors and readers to be sure I did not misrepresent, or be assumed to be misrepresenting, the sources (editors often don't check sources for things that they don't like and overwrite). In this case you have initially airbrushed away, and eventually deleted, all my sources, which I think are more reliable and authoritative on thermodynamics than the cosmological arXiv article you have regrettably cited; that arXiv article hardly considers the problems with defining entropy. I would still say that the current view of matters is complicated and very hard to simplify. I would not call it the current understanding of things, I would call it the current lack of understanding of things. How do dark matter and dark energy fit into nice simple articles about thermodynamics?
I do not at all like free-wheeling, may I even say lofty, expressions of editorial opinion such as you have written, especially based on a single source, no matter how widely cited it might be according to Google (the more widely cited, the more likely to be pseudo?); and that source admits a variety of more or less mutually incompatible thoughts about this.
I think Truesdell is right to have called the Clausius aphorism "sybillic", and that if it is mentioned at all in the article it should be nailed to Clausius and suffer some comment such as Truesdell's. For an article about the second law, I think technical the difficulty of defining entropy for the universe is more important than ideas about expansion of the universe. This article is not about cosmology, but you have come close to turning the section into such. Clausius' use of the word "universe" was hyperbolic and should not by Wikipedia be supported as if it were literally justified.
I won't argue with you about this because I can see that you are firmly intent on giving it an airing here. My preference would be to omit the section, or again call it the heat death story, making it clear that it is esoteric and of mainly historical interest for thermodynamics, no matter what cosmologists might think about it.Chjoaygame (talk) 02:19, 2 August 2013 (UTC)

reason for removal of new material[edit]

I have removed a newly inserted paragraph from the lead. The deleted material expresses an opinion that is often encountered but is, sorry to say, mistaken. The following is a statement of the true position.

A very tall adiabatically isolating vessel with rigid walls initially containing a thermally heterogeneous distribution of material, left for a long time under the influence of a steady gravitational field, along its tall dimension, due to an outside body such as the earth, will settle to a state of spatially uniform temperature though not of uniform pressure or density, and is then in internal thermal equilibrium and even perhaps in thermodynamic equilibrium.[1][2][3][4][5][6][7][8][9]

This matter has been very carefully considered by the giants of thermodynamics, and again by a semi-giant Sydney Chapman, and again by more recent experts. The temperature in the state of thermodynamic equilibrium is spatially uniform in spite of gravity. The removed material was not supported by any reference and was thus exposed to immediate removal. If it had references, they would have been carefully scrutinized, and, I think, would most likely have been detected as unreliable. This matter is not open for grabs. Sad to say, the removed material reflects the opinion of, amongst others, an inventor of a perpetual motion machine. When proposed other than by someone well intentioned but not well educated in thermodynamics, it is quite often merely pseudo-science. It will not be treated leniently here.

Even if the removed material had not been mistaken, it would have been inappropriate in the place where it was inserted, because of relevance and detail. The removed material was inserted by an editor who did not sign in with a named account. It made a major direct reference to matters of climate. While climate science uses thermodynamics, it is not appropriate to put in material like that about climate science in the lead of the article on the second law, which is primarily purely a general physical matter.Chjoaygame (talk) 01:55, 6 September 2013 (UTC)

References[edit]

  1. ^ Maxwell, J.C. (1867). On the dynamical theory of gases, Phil. Trans. Roy. Soc. London, 157: 49–88.
  2. ^ Gibbs, J.W. (1876/1878). On the equilibrium of heterogeneous substances, Trans. Conn. Acad., 3: 108-248, 343-524, reprinted in The Collected Works of J. Willard Gibbs, Ph.D, LL. D., edited by W.R. Longley, R.G. Van Name, Longmans, Green & Co., New York, 1928, volume 1, pages 55-353, particularly pages 144-150.
  3. ^ Boltzmann, L. (1896/1964). Lectures on Gas Theory, translated by S.G. Brush, University of California Press, Berkeley, p. 143.
  4. ^ Chapman, S., Cowling, T.G. (1939/1970). The Mathematical Theory of Non-uniform gases. An Account of the Kinetic Theory of Viscosity, Thermal Conduction and Diffusion in Gases, third edition 1970, Cambridge University Press, London, Section 4.14, pp. 75–78.
  5. ^ ter Haar, D., Wergeland, H. (1966). Elements of Thermodynamics, Addison-Wesley Publishing, Reading MA, pp. 127–130.
  6. ^ Coombes, C.A., Laue, H. (1985). A paradox concerning the temperature distribution of a gas in a gravitational field, Am. J. Phys., 53: 272–273.
  7. ^ Bailyn, M. (1994). A Survey of Thermodynamics, American Institute of Physics Press, New York, ISBN 0-88318-797-3, pages 254-256.
  8. ^ Román, F.L., White, J.A., Velasco, S. (1995). Microcanonical single-particle distributions for an ideal gas in a gravitational field, Eur. J. Phys., 16: 83–90.
  9. ^ Velasco, S., Román, F.L., White, J.A. (1996). On a paradox concerning the temperature distribution of an ideal gas in a gravitational field, Eur. J. Phys., 17: 43–44.

Verification failure in talk page[edit]

Two of the above references were checked and failed verification as support for claim made in the above statements. Gravitational fields are not involved in discussions about the second law of thermodynamics. They may or may not be involved in the combined first and second law. This is why such material failing verification ought not to be included within the article itself, neither in the lead nor in the body. My hope is that this editor will consider the ease with which other editors can check that "the giants of thermodynamics" never wrote such things, and that this editor will refrain from continuing to add either uncited or falsely cited content to the article. A general reader will also be served if this editor removes such uncited statements and/or verifiably falsely-cited statements that he or she has added in the past. Flying Jazz (talk) 06:47, 27 April 2015 (UTC)

In the flood of attacks by the above editor, I did not notice this one, perhaps partly because it has a title similar to another, below on this page. Now that I have noticed it, I see that it seems to be mistaken. In the other place, below on this page, where the above editor made more or less the same attack, he wrote that he had checked a Planck reference and a Maxwell reference. No Planck reference is in the above list. So it seems that of the above list, he actually checked only the Maxwell reference, and, writing in haste, did not actually check this immediately above list as such. Below I have dealt with the Maxwell reference, showing that the attack on it was mistaken. I will deal further with this flurry of attacks below at that place.Chjoaygame (talk) 07:12, 30 April 2015 (UTC)

reasons for removal of repeat of faulty edit[edit]

I have to say I am sorry I did an incomplete removal of the faulty edit of 6 Sep 2013 by an unnamed editor.

A near repeat of that faulty edit has been posted by editor Douglas Cotton.

I have now completed the removal of the original faulty edit as well as undoing the new posting by editor Douglas Cotton.

The reasons are several. One is that the original faulty edit and its new version are unsourced. Another is that the edit is in the lead but is not a part of a summary of the article content. Another is that the edit strays into climate theory, far beyond what is appropriate for the lead of this article. The strongest reason is that the edit is thoroughly wrong in physics. The evidence with sources that the edit is wrong is given in the first part of this talk page section. I have added another reference to a reliable source (ter Haar and Wergeland 1966) to the above reference list.

I may add that Loschmidt was responsible for a proposal that would lead to the faulty edit, but that Loschmidt was mistaken, and was corrected in his day. It is also the case that some experiments have been performed purporting to test the matter empirically, which have been interpreted to support Loschmidt. But the experiments are not of a good enough quality to reliably test the matter. For Wikipedia, at best they constitute unverified primary research and reports of them do not constitute reliable Wikipedia sourcing. They are therefore not admissible in the article. I mentioned in my previous remarks about this that faulty editing of the kind posted by editor Douglas Cotton will not be treated leniently here.Chjoaygame (talk) 08:53, 16 February 2014 (UTC)

edit on Maxwell's demon[edit]

I have removed the unsourced comment, as well as its newly proposed replacement. The comment was unsourced for too long. The newly proposed replacement is primary research, not adequately supported by reliable secondary sources. And evidently not to the point. Information erasure is not information acquisition.Chjoaygame (talk) 00:50, 31 December 2013 (UTC)

non-equilibrium[edit]

The article contains the following piece of wisdom:

"The entropy of a system that is not in equilibrium can be defined as:
S = -k_{\mathrm B}\sum_{j}P_{j}\ln\left(P_{j}\right)
see here. Here the P_{j} is the probabilities for the system to be found in the states labeled by the subscript j. In thermal equilibrium, the probabilities for states inside the energy interval \delta E are all equal to 1/\Omega, and in that case the general definition coincides with the previous definition of S that applies to the case of thermal equilibrium."

I have recently discovered by advanced methods of scientific research that P(j) = the length of a piece of string.

If someone has a better estimate than this, perhaps they may have a case to retain this piece of wisdom. But, unless the estimate is mightily better, I am keen to delete this piece of wisdom.Chjoaygame (talk) 16:07, 19 January 2014 (UTC)

Done.Chjoaygame (talk) 09:10, 16 February 2014 (UTC)

Style of article[edit]

The entire article is written in a style that only a scientist or a science major can fully grasp. It assumes that the ordinary layman can understand all this, which is not the case. It should be rewritten in a style that is intelligible to people who are not scientists. AlbertSM (talk) 16:54, 13 February 2014 (UTC)

In particular, note the interpretation of dq.... as an "infinitesimal" is at odds with the universal teaching of calculus that dq is a real number. To most non specialists this is nonsense - it conveys no useful information. Pondhockey (talk) 04:10, 22 July 2015 (UTC)

why Planck's statement is preferable[edit]

I have undone a good faith edit. The edit that I undid replaced Planck's preferred statement of the second law with a statement by another writer.

Planck's statement is preferable for several good reasons.

One is that Planck is recognized by another reliable source as a most excellent and reliable authority, a fact known to many without need for that particular reliable reference. The proposed new statement is not backed up by a reliable source for its excellence.

Another is that Planck's statement is better than the one from the other writer. This is because Planck is well aware of, and has elsewhere explicitly stated, the difficulty or impossibility of defining entropy for a system not in thermodynamic equilibrium. The other writer's statement talks about changes in the entropy of an isolated system. This can have strict meaning only if the isolated system is a compound of several simple systems each with its own internal state of thermodynamic equilibrium, the compound being in some initial equilibrium state, and then a thermodynamic operation changes the connections between the subsystems and sets in progress some thermodynamic processes which lead to a new compound equilibrium state. The recounting of this complicated story is avoided by Planck's better formulated version. Planck's version takes the story into account. It avoids the possible suggestion, present in the other writer's version, that a simple isolated system might change its entropy, a suggestion rife with problems, as observed by Planck.Chjoaygame (talk) 10:30, 2 March 2014 (UTC)

reasons for undo[edit]

I have undone an inappropriate edit. There are several reasons why that edit was inappropriate and perhaps even improper.

The edit was an addition to the lead, of a detailed piece of reasoning that is not covered in the article. The lead is the place for summary of the article, not for presentation of new detailed reasoning. The edit concerned the precise definition of a thermodynamic process involving several thermodynamic systems. This varies from text to text, and the lead of the article on the second law is not the place to analyze this.

The analysis offered in the undone edit was not sourced, and was evidently an expression of editorial opinion or point of view verging on original research which is not allowed by Wikipedia policy.

Perhaps also a problem might be that the edit was anonymous and perhaps idiosyncratic, and the question arises whether it might have been a case of sock-puppetry, which is forbidden in Wikipedia.Chjoaygame (talk) 02:28, 4 March 2014 (UTC)

Prigogine & Stengers quote[edit]

I have restored the just-previously removed quote from Prigogine & Stengers. Prigogine is a Nobel Prize winner, for his work on non-equilibrium thermodynamics, with special reference to the second law, that, largely speaking, showed how the second law is compatible with the evolution of life. The second law is sometimes seen as a statement that nature tends to disorganization, while the evolution of life is sometimes seen as a development of organization in nature. The two are compatible and it is worth saying that in an article on the second law. The reason is that the second law refers primarily to systems that are in thermodynamic equilibrium while the evolution of life is essentially rooted in systems that are not in thermodynamic equilibrium. Prigogine and others have shown that there is no incompatibility in that. It is useful to remind readers of this in this article.Chjoaygame (talk) 07:09, 6 March 2014 (UTC)

I made the removal of the quote, and I still find it to be irrelevant on the article as it stands. If there had been a section with common misconceptions of the second law, i.e. that it "refutes evolution" the quote could be entirely appropriate. However, without that context, I would say that the quote seems out of place.Tuxino OKH (talk) 03:25, 7 March 2014 (UTC)
One or two of the other quotes are nonsensical or poorly stated. I suppose you could object to them too. Though I think you are being stringent, just to make you happy, I have deleted the one you find irrelevant. Along with it I have removed one that offers a defective statement of the law, and a moral view that the Prigogine quote was intended to counter.Chjoaygame (talk) 10:35, 7 March 2014 (UTC)
The reason I didn't object to any of the other quotes is that they dealt directly with thermodynamics, whereas the one I removed was only related to the subject in a rather roundabout way. And, yes I suppose I am somewhat stringent. I have no objection to your removal of the other quote. Tuxino OKH (talk) 20:46, 7 March 2014 (UTC)

"a quote from a primary source"[edit]

This edit explained itself in its cover note on the grounds that the version it removed was "a quote from a primary source".

Not so. The quote is from a 2003 authoritative review by J. Uffink, published by Princeton University press, of the literature including secondary sources. Primary sources on the second law of thermodynamics are for example Carnot, Clausius, Rankine, and perhaps Kelvin, early and middle nineteenth century authors. Planck's 1926 article was an authoritative review, particularly assessing the Carathéodory view. Planck's textbook has been through 11 editions because of its accepted authority. It is not a primary source. It is at least a secondary source, and Uffink's review, from which the quote was copied, is a reliable tertiary source, which explicitly recognized the authority of Planck on this matter.Chjoaygame (talk) 09:13, 10 March 2014 (UTC)

reasons for undo[edit]

I have undone another attempt to put into the article a repeated claim that is contrary to reliable sources. The attempt was unsourced and was placed out of context. The context was the possibility of black holes affecting the applicability of the second law, but the attempt was about planetary atmospheres, not black hole possibilities. The attempt comes from a mistaken belief which has been repeatedly expressed by edit attempts here, made by the same editor, who elsewhere is promoting a book he has written about the subject. The attempt is fringe science, and contradicts the consensus of Maxwell, Boltzmann, Gibbs, and Chapman, as well as of other modern authors.Chjoaygame (talk) 07:43, 18 March 2014 (UTC)

undid self-promotion that also happens to contradict reliable sources.[edit]

I have undone a set of edits which were self-promotion. The cited source was a publication by the editor who posted the edits which I undid. It is against the rules of Wikipedia for an editor promote his own research and publications, WP:PROMOTION. As it happens, the publication expresses a doctrine that is contradictory to reliable sources, so that even if it had been posted and cited by someone else, the edit that cited it would have needed to be undone. The doctrine promoted in the publication contradicts many reliable sources in many respects. It is not the kind of thing that is acceptable in Wikipedia; it may be described as fringe science masquerading as mainstream science. The editor who posted this material has several times recently tried to post material substantially like it, and the posts have been undone for the same reasons. The Wikipedia has a strict rule, WP:OR, against edits which are original research, including original synthesis, WP:SYN, of the research of others. A primary rule of Wikipedia is that material must have reliable sources, WP:RS. Many reliable sources are contradicted by the edits which I have undone.Chjoaygame (talk) 12:30, 29 March 2014 (UTC)

faulty edit undone[edit]

I have undone a sequence of faulty edits.

The edits were an attempt to post parts of several previous faulty edits along the same lines. The repeated creation of a need to undo these faulty edits raises the question of disruptive editing. The faulty edits are obviously in good faith in the sense that they represent the faulty editor's beliefs about what should rightly be in the article. But they are repeated without regard to reasons for their previous undoing given on the talk page. The reasons slready given on the talk page are sound and should not be ignored. It is perhaps useful that I repeat here that the faulty edits are in support of promotion of a recent publication of original research of the editor who posted them, and that he has been persistently trying to post this doctrine, which contradicts reliable sources.

The faulty edits amount to the insertion of the following into the lead:

"In order to understand how the process described in this law leads to gradients in density etc in a gravitational system (where gravitational potential energy must also be taken into account) we refer to the fact that the state of thermodynamic equilibrium has no unbalanced energy potentials. Hence it has homogeneous entropy and may be said to be isentropic. If this were not the case, then entropy could still continue increasing, because the state of maximum entropy (within the system constraints) would not have been attained."

The present faulty edits are unacceptable for several reasons.

In general, they are a chatty explanation in the lead, but are not an appropriate summary of the context of the contents of the article. The explanation they give is not well enough expressed for lead explanation, even if one were appropriate here. Talk of "unbalanced energy potentials" is too vague for a lead explanation.

Morevover, they are faulty in physics. One reason for this statement is that it is not correct in context in physics to say that "the state of thermodynamic equilibrium has no unbalanced energy potentials". This claim in context includes gravitational potential energy. Beyond the vagueness of the phrase "unbalanced energy potentials" is that thermodynamics is not about energy potentials loosely taken, it is specifically about thermodynamic potentials. A gravitational potential is not a thermodynamic potential. Another reason is that the claim about homogeneous entropy is wrong in physics. The condition for thermodynamic equilibrium in a body is that its total entropy be maximum subject to the constraints, not that its entropy density be homogeneously distributed. Moreover, the use of the term "isentropic" is wrong. Isentropic refers to thermodynamic processes, not to a distribution of entropy density as is obviously intended in the faulty edit.

I am sorry to say that if this kind of attempt should be repeated, I would feel that I should seek some kind of administrative remedy.Chjoaygame (talk) 06:29, 30 March 2014 (UTC)

The Second Law of Thermodynamics article has serious omissions.[edit]

request for comment from local editors[edit]

I would like to ask for comment from local editors about the recent edits of Editor Douglas Cotton to this and closely related pages. I am concerned mainly about conduct, but content cannot be ignored, and perhaps the two cannot be easily separated. I am asking here for comment from local editors before, and hopefully preventive of, an RfC from outside editors.Chjoaygame (talk) 14:47, 30 March 2014 (UTC)

request cancelled–problem seems solved[edit]

Editor Douglas Cotton seems to have begun to use the talk page instead of just posting his innovations immediately as edits. This seems to me to remove the potential problem of editorial conduct mentioned in the just previous comment. This is good.Chjoaygame (talk) 08:15, 1 April 2014 (UTC)

Editor Douglas Cotton, it should be noted, gained a university scholarship and degree in physics in the 1960's and has written two comprehensive peer-reviewed papers and a book about the Second Law, and developed an hypothesis pertaining to all planetary core and surface temperatures that is soundly based on the Second Law of Thermodynamics and the Kinetic Theory of Gases as used by Einstein and many others. (For details and links to the papers see http://climate-change-theory.com ) 121.217.80.138 (talk) 02:28, 3 April 2015 (UTC)

Application to pressure, density and temperature gradients in force fields[edit]

The Second Law can be used to explain and quantify density, pressure and temperature gradients in force fields, such as are empirically observed in experiments with centrifugal force, and of course observed in all planetary tropospheres and even in borehole measurements in the outer 10km of Earth's outer crust. These temperature gradients represent the state of thermodynamic equilibrium with maximum entropy, which is of course what the Second Law says will evolve. In short, energy potentials have dissipated when the mean sum of molecular kinetic energy and gravitational potential energy is homogeneous at all altitudes. The density gradient stabilizes when there are equal numbers of molecules passing up and down across any horizontal plane, and also, the mean kinetic energy of those molecules is equal for those coming from above and those from below. Since pressure is proportional to the product of density and temperature, these two conditions ensure pressure is the same from above and below each horizontal plane, and so there is stability which is characteristic of maximum entropy. But the conditions make it clear that molecules in flight between collisions as they cross any horizontal plane must have had less kinetic energy at a higher level and more kinetic energy at a lower level. This leads to us understanding that the temperature gradient is the state of thermodynamic equilibrium. It also allows us to understand that, if new thermal energy is absorbed in a troposphere which is in thermodynamic equilibrium with a temperature gradient, then that new energy will spread out in all accessible directions over the sloping thermal plane, with some heat diffusion and natural convection downwards towards warmer regions and the surface. This obviates the need to "explain" heat transfers into the surface by radiation from a colder atmosphere, which would of course violate the Second Law. Such heat transfers can only happen by heat diffusion and natural convective heat transfer (involving kinetic energy transfer in molecular collisions) because of the action of gravity upon individual molecules whilst in flight between collisions. 121.217.80.138 (talk) 02:29, 3 April 2015 (UTC)

TEMPERATURE GRADIENT CAUSED BY GRAVITATION[edit]

The following paper supports the deduction above that the entropy maximization described in the Second Law of Thermodynamics leads to there being a temperature gradient in a force field such as gravity.

Chuanpingliao International Journal of Modern Physics B (Impact Factor: 0.46). 01/2012; 23(22). DOI: 10.1142/S0217979209052893 ABSTRACT Thermodynamic deduction and experimental results both demonstrate that gravitation causes temperature gradient in an adiabatic system, i.e., gravithermal effect: The higher altitude the lower temperature. (See:http://www.researchgate.net/publication/263879139_TEMPERATURE_GRADIENT_CAUSED_BY_GRAVITATION ) 121.217.80.138 (talk) 02:27, 3 April 2015 (UTC)

I have spent some time checking the paper cited just above here, and references in that paper. The citation data offered just above here contains errors, and I had to spend time circumventing those.
From this checking I can report that the paper cited just above here is nowhere near to being a reliable source, and cannot be cited as a source in a Wikipedia article. It contains elementary errors of physical reasoning.Chjoaygame (talk) 06:23, 3 April 2015 (UTC)
Could we please have an explanation of these elementary errors of physical reasoning, and if possible a source to support the claim that they are errors? I am not familiar enough with this debate to decide whose physics is correct, but I do think that we should be more careful to respect Wikipedia policy. At the moment we have a source article which has been published in a refereed journal but which has been declared nonreliable by a pseudonymous (as are we all) Wikipedia editor without either arguments or another source. It is true that the article is a primary source whereas secondary sources (such as review articles) are preferred, but that does not seem a sufficient reason to overrule it without proper explanation. Dirac66 (talk) 02:44, 4 April 2015 (UTC)
I think it fair to draw attention to the circumstances here. Responding at all to the above capitalized post might attract a charge of feeding the trolls, and perhaps I was wrong to respond at all. There is a solid consensus of reliable sources on the question. In the current round of related posts, we are looking at a fringe view that is being repeatedly pushed by an editor who posts in various places under various names, partly to evade bans, and who has tried to promote his self-published book on the question. His view contradicts the solid consensus of reliable sources. The reliable sources have been posted before on this or related pages and are given in the article where this matter really belongs, at Thermodynamic equilibrium#Uniform temperature.Chjoaygame (talk) 17:32, 4 April 2015 (UTC)
That the matter is brought up here is another way of evading the weight of those sources where they belong. Here they are again: "The temperature within a system in thermodynamic equilibrium is uniform in space as well as in time. This is so in all cases, including those of non-uniform external force fields.[1][2][3][4][5][6][7][8][9]"
The article that is cited in the capitalized post makes a basic error of physics, which repeats that of the poster. It arbitrarily and gratuitously adds a term for gravitational potential energy to the list of component terms for the internal energy. As not too often clarified in texts, but made explicit by Crawford's 1963 text, the total energy of a body is often expressible as the sum of three terms, the internal energy, the kinetic energy of the motion of the body as a whole, and the potential energy of the body as a whole in the externally imposed force field, for example gravity. Putting the externally imposed potential energy into the internal energy is a basic mistake.
Another basic mistake is the confusing of kinetic theory reasoning with thermodynamic reasoning. The kinetic energy of a molecule is reduced by conversion into potential energy as it rises, but only the initially faster molecules rise very high. The statistics just balance so that the temperature remains uniform.
Another basic mistake is to confuse non-equilibrium situations with equilibrium situations. There is no general law about temperature uniformity for non-equilibrium situations. They are not directly addressed by the second law, but are mistakenly cited as evidence for a mistakenly imagined "gravito-thermal effect". Forces that sustain non-equilibrium situations often create non-uniformity of temperature, but this is not evidence about equilibrium.
Citations
  1. ^ Maxwell, J.C. (1867).
  2. ^ Gibbs, J.W. (1876/1878), pp. 144-150.
  3. ^ Boltzmann, L. (1896/1964), p. 143.
  4. ^ ter Haar, D., Wergeland, H. (1966), pp. 127–130.
  5. ^ Bailyn, M. (1994), pp. 254-256.
  6. ^ Chapman, S., Cowling, T.G. (1939/1970), Section 4.14, pp. 75–78.
  7. ^ Coombes, C.A., Laue, H. (1985). A paradox concerning the temperature distribution of a gas in a gravitational field, Am. J. Phys., 53: 272–273.
  8. ^ Román, F.L., White, J.A., Velasco, S. (1995). Microcanonical single-particle distributions for an ideal gas in a gravitational field, Eur. J. Phys., 16: 83–90.
  9. ^ Velasco, S., Román, F.L., White, J.A. (1996). On a paradox concerning the temperature distribution of an ideal gas in a gravitational field, Eur. J. Phys., 17: 43–44.
Cited bibliography
  • Bailyn, M. (1994). A Survey of Thermodynamics, American Institute of Physics Press, New York, ISBN 0-88318-797-3.
  • Boltzmann, L. (1896/1964). Lectures on Gas Theory, translated by S.G. Brush, University of California Press, Berkeley.
  • Chapman, S., Cowling, T.G. (1939/1970). The Mathematical Theory of Non-uniform gases. An Account of the Kinetic Theory of Viscosity, Thermal Conduction and Diffusion in Gases, third edition 1970, Cambridge University Press, London.
  • Crawford, F.H. (1963). Heat, Thermodynamics, and Statistical Physics, Rupert Hart-Davis, London, Harcourt, Brace & World, Inc.
  • Gibbs, J.W. (1876/1878). On the equilibrium of heterogeneous substances, Trans. Conn. Acad., 3: 108-248, 343-524, reprinted in The Collected Works of J. Willard Gibbs, Ph.D, LL. D., edited by W.R. Longley, R.G. Van Name, Longmans, Green & Co., New York, 1928, volume 1, pp. 55–353.
  • Maxwell, J.C. (1867). On the dynamical theory of gases, Phil. Trans. Roy. Soc. London, 157: 49–88.
  • ter Haar, D., Wergeland, H. (1966). Elements of Thermodynamics, Addison-Wesley Publishing, Reading MA.
It is claimed in the cited paper, and in other papers, that experimental evidence advanced therein disposes of the theoretical consensus. There has been published (sorry, I don't have the source at my finger tips, nor time and inclination to hunt it down; if you think it should be found, you have found a way to do a public service) a criticism that effectively disposes of the previously claimed experimental "evidence".
One or two of the papers quoted by the cited paper accept the uniform temperature rule. Others don't consider the question.
Editors who were not happy with this reply of mine would be free to read the cited article and assess it for themselves.Chjoaygame (talk) 13:06, 4 April 2015 (UTC)Chjoaygame (talk) 13:46, 4 April 2015 (UTC)
OK, thank you very much for this detailed reply. I now agree that we have sufficient reason to justify not using the cited paper. I will confess that I suspected it was wrong, since it suggests the possibility of a perpetual motion machine to somehow convert thermal into gravitational potential energy, but of course suspecting is very different from being able to justify properly.
I think we should also mention briefly in this article that equilibrium implies uniform temperature, with a link to the detailed and sourced presentation at Thermodynamic equilibrium#Uniform temperature. The fact is a useful consequence of the second law since it implies that vertical temperature gradients must be maintained by continual energy inputs, as in the deep ocean or the atmosphere. Dirac66 (talk) 14:37, 4 April 2015 (UTC)
Thank you for this support. I have added a link to the comments about this in the lead of the article.Chjoaygame (talk) 17:36, 4 April 2015 (UTC)

Clausius statement is a corollary only in horizontal plane[edit]

From the above discussion we see that the Clausius "hot to cold" statement is really only a corollary of the Second Law which is only applicable in a horizontal plane. That should not surprise anyone, because the equation used for entropy in the proof of that statement has no term for gravitational potential energy. 121.217.80.138 (talk) 02:29, 3 April 2015 (UTC)

independent processes, not participating systems[edit]

The text ought to read "in every independent natural process in an isolated system" and not refer to the "sum" in "participating systems." Such participating systems (in reality they are processes) would have to be dependent, and so, in effect, they comprise a single independent process. For example, consider what happens in the two sides of a siphon which could be considered two dependent processes or one independent process. The Second Law explains why water can flow up one side of a siphon provided that it flows down further on the other side. If you cut the hose at the top you then have two independent processes. 121.217.80.138 (talk) 02:34, 3 April 2015 (UTC)

Entropy maximized by fastest route[edit]

As discussed at http://entropylaw.com new understandings (since 1988) include the fact that entropy will be maximized by the fastest available route. They draw an analogy with a warm log cabin in the snow, wherein it will cool through whatever windows or doors are open and allow the fastest overall rate of cooling. 121.217.80.138 (talk) 02:34, 3 April 2015 (UTC)

link to dissipation[edit]

The first clause of the first sentence of the lead reads "The second law of thermodynamics states that the entropy of an isolated system never decreases." The law refers to all modes of increase of entropy, not only dissipative modes. Planck pointed out that diffusion in an ideal gas mixture increases entropy but is not a form of dissipation of energy.<Planck, M. (1897/1903). Treatise on Thermodynamics, translated by A. Ogg, Longmans Green, London, p. 100.> The link misleadingly suggests that all increases of entropy are due to dissipation. This is not a reason to expand the first clause; it is a reason to remove the link.Chjoaygame (talk) 18:28, 30 March 2014 (UTC)

undid faulty edit[edit]

I have undone a faulty edit. The faulty edit was another repetition of the string of edits by the editor who posted it, edits which contradict the reliable sources which concur in saying that in a system isolated apart from being subject to an externally imposed force field, in the present of such a field, the state of internal thermodynamic equilibrium is characterized by spatial homogeneity of temperature. The reliable sources are listed at Thermodynamic equilibrium#Characterisitics of a state of internal thermodynamic equilibrium#Uniform temperature.

It seems to me that the repeated posting of faulty edits such as this one has become a matter of editorial conduct.Chjoaygame (talk) 11:16, 31 March 2014 (UTC)

Editor Douglas Cotton seems to have begun to use the talk page instead of just posting his innovations immediately as edits. This seems to me to remove the potential problem of editorial conduct mentioned in the just previous sentence. This is good.Chjoaygame (talk) 08:12, 1 April 2014 (UTC)

Douglas Cotton, it should be noted, gained a university scholarship and degree in physics in the 1960's and has written two comprehensive peer-reviewed papers and a book about the Second Law, and developed an hypothesis pertaining to all planetary core and surface temperatures that is soundly based on the Second Law of Thermodynamics and the Kinetic Theory of Gases as used by Einstein and many others. (For details and links to the papers see http://climate-change-theory.com )

The Second Law is not just about temperatures or "hot to cold"[edit]

formulations[edit]

Prigogine in 1978 wrote: "I should emphasize that 150 years after its formulation the second law of thermodynamics still appears to be more a program than a well-defined theory in the usual sense, as nothing precise (except the sign) is said about the S production."<Time, structure, and fluctuations, Science 201: 777–785.>Chjoaygame (talk) 22:27, 15 April 2014 (UTC)

decay or evolution[edit]

The opening paragraph reads "always evolve toward thermodynamic equilibrium". thermodynamic systems do not "evolve" they decay towards equilibrium. (ref Peter Atkins - Creation Revisited). So I propose replace "evolve", which gives entirely the wrong sense to the general reader, with "decay". Vh mby (talk) 12:50, 18 May 2014 (UTC) It seems no one has any problem with this.. (done) Mike 23:29, 25 May 2014 (UTC)

I moved the immediately above comment to the usual place for new comments, here, at the end of the article, in a new section.
As it happens, I don't agree that "evolve" gives entirely the wrong sense to the general reader. I see evolve as a fairly neutral word, while decay has a suggestion of deterioration. Peter Atkins is only one of many writers, and on such matters as this, he is not authoritative. Since I am not happy with the lead statement of the law anyway, I am not now going to try to tweak it.Chjoaygame (talk) 05:22, 26 May 2014 (UTC)

request to clarify definition of heat[edit]

To any editors listening... A recent discussion at SkepticalScience (Sk), which has a very long comments section for a post about the Second Law and its relationship to the Greenhouse effect, has highlighted for me a problem with the current version of Clausius's statement. Many people don't understand that the heat flow being described is net heat. That heat can flow in both directions and the 2nd law simply requires that the flow from hot to cold be the greater so that the net is from hot to cold.

Some people latch onto the simpler form in the current statement to assert that Clausius didn't mean net because he didn't say it explicitly in that statement. This is then used in some wild arguments that the GH Effect violates the 2nd Law.

The conversation at SkS actually looked at various statements by Clausius, including others that more explicitly mentions the allowed bi-directional nature of the heat flux.

It would be worth while to expand the section on Clausius's statement to incorporate his more nuanced view from other statements and clarify his meaning.

The SkS discussion can be found here: http://www.skepticalscience.com/Second-law-of-thermodynamics-greenhouse-theory-basic.htm. Go to page 29 of the comments, comment 1446 by Dikran Marsupial citing Clausius and Tyndal's translation

Thanks Glenn Tamblyn (talk) 01:55, 26 August 2014 (UTC) Glenn Tamblyn

I moved the immediately above comment by Editor Glenn Tamblyn from further above to here as the usual place for new comments.Chjoaygame (talk) 10:33, 27 August 2014 (UTC)
I put in an explicit reminder as requested.Chjoaygame (talk) 10:52, 27 August 2014 (UTC)

Thanks Chjoaygame. Newbie here so I will leave it to others to discuss. 124.181.32.174 (talk) 11:56, 28 August 2014 (UTC)

New commentary from Clausius[edit]

Editor Glenn Tamblyn has supplied some new commentary quotes from Clausius. They are not statements of the second law. Indeed they directly contradict the second law, which says that natural processes are accompanied by increase of entropy. The Clausius comments are not about natural processes, but are instead about idealized or fictive mathematical quasi-processes, which can be prescribed to be reversible. The purpose of that is to define entropy, not to state the second law. The point of the second law is that natural processes are irreversible. The presence of the new commentary quotes from Clausius is therefore, in my opinion, misleading to a reader not already well familiar with the subject. I do not think it a good idea to add at this point in the article the detail that fictive quasi-processes can be made reversible. I think the new commentary should be removed.Chjoaygame (talk) 06:47, 16 September 2014 (UTC)

Edit re violations on short time scales[edit]

I am concerned that the recent edits by 122.177.32.77 (here and at Entropy) may have been dismissed too quickly. Yes, any claims of violating the second law are shocking. But in this case the added seven-line section was supported by references to articles in five leading physics journals, and two of the article titles (in Physical Review Letters and Physical Review E) even include the words violations and violating. So I don't think the material should be totally excluded from the Wikipedia article on the subject. I have not read the cited articles, so I admit the possibility that the edits in question were not accurate, but in that case the Wikipedia article should explain why and not just ignore the articles, given the importance of the sources.

Also, I do not understand the claim in the edit summary for the deletion to the effect that The second law does not refer to short time scales. Our article lead says that The second law of thermodynamics states that the entropy of an isolated system never decreases, Taken literally, never means not even for a picosecond (or less). If current research shows that it actually means never for more than 0.1 s [timescale mentioned in the deleted edit at Entropy, then I think the Wikipedia article should explain that. Dirac66 (talk) 00:18, 5 October 2014 (UTC)

Good to see this careful commentary.
Wikipedia lead statements of the laws are controlled by forces unknown to Newton. I made the edit on the assumption of a properly valid statement of the law, nearly as per Planck, which latter sadly was not acceptable to the forces. It is a sad fact that there is no unique, rigorous, and straightforward definition of entropy for a system not in its own state of internal thermodynamic equilibrium. Plenty of people wish there could be such a definition but the facts are painfully otherwise. To deal with non-equilibrium situations rigorously, one needs two- or more-time entropies. Not considered in this article. Various half measures are of course proposed by various experts, but they are still half measures. This article at present is not set up to consider such half measures.
Even Planck's most careful statement is not perfectly watertight and cast iron. If one wants to state the second law in terms of entropy, a proper statement is a tightened version of Planck's; something like the following: There may be initially given two or more thermodynamic systems, each in its own state of internal thermodynamic equilibrium. Then there may be a thermodynamic operation that initiates a thermodynamic process of transfer between the systems. The new arrangement of systems proceeds to a final state with all systems in their own states of internal thermodynamic equilibrium. Then the sum of the entropies of final states is greater than the sum of the entropies of the initial ones.
I can imagine what horror might be expressed if one tried to put this up. But it expresses, perhaps clumsily, a proper and valid statement of the law.
It would be lovely if one could say more. But I think it would be self-deception to do so. (1) The hardest point is that some like to imagine that some magical mathematical procedure will create a straightforward one-time entropy that will rigorously tell the direction of a process that doesn't start or finish with states of internal thermodynamic equilibrium. (2) Some like to forget that a process that starts from equilibrium needs something to start it, and it needs a mythically infinite time for it to finish itself. It is perhaps pleasant or convenient to try to hide or gloss over these two facts, but it is not good thermodynamics.
True, one never actually knows if one is dealing with a system that has waited long enough (inifinitely long) to reach its own internal thermodynamic equilibrium. But thermodynamics has its limits and that is one of them. It just postulates that one does know.
Small systems that show detectable fluctuations, and rapid processes that show up fluctuations, are specialist subjects, and I think they need explicitly specialist and properly thorough expression. I think they should not be tagged onto basic classical thermodynamics as afterthoughts.
I am suspicious that the edits in question were promotion, but that is only a subsidiary reason for undoing them. The decisive reason is as I have proposed just above.
That the lead is unsatisfactory is not, I think, I reason to allow other faults to come into the article.Chjoaygame (talk) 15:20, 5 October 2014 (UTC)
Thanks for your reply. I had not realized that the intro is still unsatisfactory. Perhaps you can try again to correct it and add sources. I note that the intro is now unsourced except for two references at the end of the third paragraph. This may be ok for some articles, but not for a subject as difficult and controversial as the second law of thermodynamics.
For now I am concerned with the recently deleted edit by 122.177.32.77. I think the experiments mentioned are important and do belong in the article, but perhaps they can be described without actually saying in Wikipedia’s voice that they are violations of the second law. So I propose restoring the text with some modifications.
  1. Change section title to Statistical interpretations of the second law of thermodynamics and fluctuations
  2. Change second sentence of section to Entropy fluctuations over short time scales in the case of trajectory of colloidal particles in water held in an optical trap have been experimentally demonstrated, and described by the authors as violations of the second law.
  3. Add comment after the above sentence: this assumes that entropy can be defined when a system is not at equilibrium.
As for fluctuations being a specialist subject, I think they should be mentioned briefly to inform the reader that they exist, and avoid implying that entropy can never decrease under any circumstances. A short section (here 7 lines) is sufficient if it includes a link to a relevant main article (such as Fluctuation theorem ?) for the few readers who want more details.
And I don’t worry about promotion (conflict of interest) here because the sources are refereed papers in leading journals. It is more a concern when the sources are personal websites or advertisements. Dirac66 (talk) 01:25, 6 October 2014 (UTC)
"Thanks for your reply." Good to see your careful considerations.
"I had not realized that the intro is still unsatisfactory. Perhaps you can try again to correct it and add sources. I note that the intro is now unsourced except for two references at the end of the third paragraph. This may be ok for some articles, but not for a subject as difficult and controversial as the second law of thermodynamics." I think it can be ok to write without explicit sourcing in the lead (I distinguish the lead from a separate section that is labeled 'introduction', as here). I agree that the material in the lead should be well and properly sourced somewhere in the article, but I think it is often good enough if the sourcing is deeper within the article. The lead is a summary. I will perhaps comment more on the present lead in due course. I am not persuaded that the second law is difficult or controversial, except where "improved" versions of it are concerned. I think the "improvements" can easily create problems. Indeed I think they can be manufactured in order that they should create problems that then call for "solutions".
"For now I am concerned with the recently deleted edit by 122.177.32.77. I think the experiments mentioned are important and do belong in the article, but perhaps they can be described without actually saying in Wikipedia’s voice that they are violations of the second law." We are looking at a suite of edits, in this and the Entropy article. In the Entropy article, the edits are from user 122.177.32.77, the same as the author of the ones in this article. They are a fair few and I think I may fairly ask discussants here to look for themselves rather than that I try to list them all here. That user 122.177.32.77 is apparently focused on this one issue, and has been diligent and persistent in driving his cause. The edits mostly culminate in a section about "Entropy changes in a Thermodynamic Process Under Potential Gradients", by Sinha Dhiraj. They refer to the Hamiltonian of the system. This is not part of classical thermodynamics. If at all, it should be presented in its own right in a suitable place, not as an appendage to the classical discussion. It has a strong flavor of presentation of personal work, which I regard as very suspicious of conflict of interest, a thing to be carefully guarded against, and worried about very much, I think. The word soapbox comes to mind.
An example of my undoing actions is here. The undone lead-in has a strongly personal appearance: "In a recent work published in Physica A, a leading peer reviewed international journal of statistical physics, Dhiraj Sinha has presented a novel formulation of the second law of thermodynamics while incorporating the role of conservative vector fields in entropy changes." We seem to be looking at steps to work around my undoing actions. The experiments mentioned as lead-in are discussed in Wikipedia in other places, where they are more appropriate. I think they are put here just in order to provide cover for the Sinha personal work. I agree with Editor Materialscientist that we seem to be looking at "undue promotion of recent primary research". For me, it is not enough that material be sourced from "refereed papers in leading journals". In general, Wikipedia editors are assumed (rightly I think) to be not competent to judge the reliability of such material.
I could spend much time writing more about this, but I hope that the above is enough to persuade editors that my undoings are justified. I am not in favor of the kinds of change you suggest.Chjoaygame (talk) 03:17, 6 October 2014 (UTC)
All right, I appreciate your opinion. I have now noticed that the article already has an adequate section on Non-equilibrium states, which contains the important information including two references to Evans and Searles - one theoretical and one experimental paper. So I will agree that we do not need the other section which you have deleted. I will just make some minor changes to the existing section - such as adding the word fluctuation to the section title so that it shows up in the Table of contents, and rewriting the sentence with the word spacetime which is elsewhere usually associated with special relativity. Dirac66 (talk) 23:37, 6 October 2014 (UTC)
Thank you. Please would you consider waiting a few hours. I have an urgent appointment and will be back later. Looking at the section on 'Non-equilibrium states, I see some regrettable faults. I have done some thinking about this matter recently, but not written it up.Chjoaygame (talk) 00:13, 7 October 2014 (UTC)Chjoaygame (talk) 00:22, 7 October 2014 (UTC)
OK, I will wait. Dirac66 (talk) 01:44, 7 October 2014 (UTC)
Thank you.Chjoaygame (talk) 05:28, 7 October 2014 (UTC)
Thank you. Now I have had a shot at it.Chjoaygame (talk) 07:50, 7 October 2014 (UTC)

Two or several-times entropies?[edit]

To Chjoaygame: I think that your edits of the last 48 hours have improved both the lead and the section on non-equilibrium states. I have changed two sentences to make them clearer, hopefully while preserving your intended meaning. A third sentence which I find mystifying is the one about two- or several-times entropies, but I have just discovered that the source book by Attard is in our university library, so I will (eventually) check it out. Could you insert the relevant page number(s)? And is two- or several-times entropies the exact term used by Attard? Also, perhaps if this is a definition of a quantity related to entropy, it should be mentioned as a new section in the Entropy article instead of here, since the Second Law refers to ordinary entropy. Dirac66 (talk) 23:48, 8 October 2014 (UTC)

Or perhaps the article on entropy production? Dirac66 (talk) 00:13, 9 October 2014 (UTC)
Thank you. Yes, your further edits seem to me to be good.
The whole book is about the many-times entropies. I didn't think a particular page number would help. I don't recall if he uses those exact words, but they are pretty much what he says. My words are more or less ordinary language that springs to the mind of a reader of his book. I think they are suitable for the present purpose. Checking, I find on page 24 "two-time entropy". He also calls it "second entropy" and "transition entropy". He talks about "third entropy". Glancing through, I didn't find "many-times entropy" but I seem to recall it from past readings; perhaps I imagined it.
Attard is a very naughty boy. He talks all kinds of jumbled stuff about probability. He says he settles for the Popper propensity stuff. His notation is logically inconsistent and lazy. But his basic idea, of generalized entropies, is, I think, right, and worthy of mention; but hardly more than a mention. He says plenty that needs saying, but sad to say he is quick and efficient in how he says it. I don't feel I have a really good understanding of it. What matters here is that he is offering a genuine generalization of macroscopic entropy. You suggest "instead of here". Perhaps, but I think it might also be right to mention it here, to register the right direction for proper generalization. As I read it, the Attard idea is not about entropy production; that is, I think, a concept that belongs to local thermodynamic equilibrium theory.
If you really want to remove the mention of Attard's stuff I haven't a strong defence for keeping it. He should work more on it, I think. My only defence is that it is in a section that criticizes loose use of the word entropy, about non-equilibrium.Chjoaygame (talk) 04:44, 9 October 2014 (UTC)
I have seen how to edit on this device. Good!
I have followed your suggestion and removed the flaky statement. Thank you for that thought.Chjoaygame (talk) 17:33, 9 October 2014 (UTC)
That seems probably best at the level of this article. But I searched for second entropy and found that you had mentioned it in the more specialized article Non-equilibrium thermodynamics. I have included a link to that article in the Non-equilibrium section here, for those readers who are interested. Dirac66 (talk) 19:09, 9 October 2014 (UTC)

The Second Law does not say[edit]

The Second Law does NOT say "The second law of thermodynamics states that in a natural thermodynamic process, there is an increase in the sum of the entropies of the participating systems." If that were the case, then it could be used to "prove" that water could flow uphill to a lake provided it flows further downhill in another creek. — Preceding unsigned comment added by 121.218.41.105 (talk) 08:58, 11 October 2014 (UTC)

Isn't that what they call a siphon? 133.48.61.207 (talk) — Preceding undated comment added 06:28, 9 July 2015 (UTC)

You have no valid grounds for changing this version referring to every process ....

Processes in which the entropy of an isolated system would decrease do not occur, or, in every process taking place in an isolated system, the entropy of the system either increases or remains constant

That version of the 2nd law comes from the textbook An Introduction to Thermodynamics, the Kinetic Theory of Gases, and Statistical Mechanics (2nd edition), by Francis Weston Sears, Addison-Wesley, 1950, 1953, page 111 (Chapter 7, "the Second Law of Thermodynamics").


— Preceding unsigned comment added by 121.218.41.105 (talk) 09:19, 11 October 2014 (UTC)

Thank you for these comments.
There are very many statements of the second law. None of them is unreservedly perfect. It may not be easy for us to reach agreement about how it should be stated in the lead of this article. You object to the new version. You cite here another version.
Perhaps I may suggest that you might look more widely than at the version you have cited here.
There are reasons for the new version in the lead.
  • It should be brief and readily readable.
  • It should make the point that it refers to thermodynamic processes, not to physical processes in general.
  • It should be positive, not merely a negation.
  • It should be based on the best sources.
  • It should refer explicitly to real thermodynamic processes as opposed to fictive ones.
  • Very likely it should be stated in terms of entropy.
  • It should not be phrased so as to suggest that it is more widely applicable than is proper.
The new version to which you object was constructed with those reasons in mind. Perhaps that is enough comment from me for the moment.Chjoaygame (talk) 10:58, 11 October 2014 (UTC)


The 2nd law applies only to isolated systems?[edit]

Since Earth receives energy from the Sun, it is an open system. The 2nd law of thermodynamics applies only to isolated systems.

That “The 2nd law applies only to isolated systems” is a premise used to explain evolution. Objections to evolution ( Violation of the second law of thermodynamics) This interesting understanding of the law should be addressed.LEBOLTZMANN2 (talk) 20:14, 12 November 2014 (UTC)

I don't think this particular article needs to accommodate or address cranks. Rklawton (talk) 21:51, 12 November 2014 (UTC)
==================[edit]

The processes must be dependent: they are "participating" (sub-)systems within the isolated system being considered. The law cannot apply to a sum of the entropy of two or more independent processes like water flowing uphill just because it "knows" it will flow further down the other side. That only happens when the up and down processes are dependent in a siphon. Cut the hose at the top and they are independent, each then gaining entropy. The Second Law applies to all forms of energy, not just thermal (kinetic) energy. For example, it also applies to potential energy in a force field like gravity. In such a case we have thermodynamic equilibrium when (PE+KE)=constant in a vertical plane and there are thus no unbalanced energy potentials, this meaning we have maximum entropy with a density gradient and a temperature gradient, each resulting from the Second Law. The pressure gradient is a corollary. See http://climateblogcritique.homestead.com — Preceding unsigned comment added by 121.217.24.180 (talk) 10:45, 9 January 2015 (UTC)

The immediately foregoing unsigned IP comment is conflict of interest promotion by an easily recognised recidivist and is an improper comment here.Chjoaygame (talk) 13:44, 9 January 2015 (UTC)

No it's not a "conflict of interest" as the author had no significant pecuniary interest in presenting such valid physics which cannot be refuted because it is a direct corollary of the Second Law of Thermodynamics.— Preceding unsigned comment added by 121.216.226.179 (talk) 23:48, 15 February 2015 (UTC)

I have restored the above autosignature, that had been removed by the user who posted the unsigned comment. That user is an easy recognizable version of Editor User:Douglas Cotton, who is now posting from dynamically signed IP addresses.Chjoaygame (talk) 06:17, 16 February 2015 (UTC)

Contradiction[edit]

The statement "even in the presence of the externally imposed unchanging external force field" is contradictory to the fourth paragraph wherein there is a correct explanation regarding external force fields and when they do or do not have an effect on temperature. A force field, such as the centrifugal force field in a Ranque-Hilsch vortex tube, causes there to be a temperature gradient, such as in the radial cross-section of that vortex tube, and in a planet's troposphere subjected to gravitational force. This results directly from the Second Law of Thermodynamics because, when the sum of molecular potential energy (relative to the force field) and kinetic energy is homogeneous there are no unbalanced energy potentials, and thus maximum entropy exists. The fourth paragraph includes the condition "subject to the condition that the compound system moves as a whole within that field" whereas that condition is not repeated in the next paragraph which thus incorrectly generalizes the statement regardless as to whether or not the "compound system moves as a whole within that field." For example, when wind descends vertically above the South Pole we have a case of "the whole system" moving and thus cold air from the upper troposphere is conveyed to the surface at similar temperatures without there being sufficient time for gravity to form the temperature gradient that it normally does in calm conditions in any planetary troposphere, regardless of whether or not there is a surface at the base thereof or any penetrating solar radiation reaching the lower troposphere.

— Preceding unsigned comment added by 121.216.226.179 (talk) 23:17, 15 February 2015 (UTC)

I have changed the syntax of the fourth paragraph of the lead to indicate more clearly that it covers the fifth paragraph.
The proposals in the above unsigned comment by IP editor 121.216.226.179 mostly refer to systems not in thermodynamic equilibrium. They are therefore not applicable to the second law for processes that start and finish with the compound system in thermodynamic equilibrium.Chjoaygame (talk) 06:40, 16 February 2015 (UTC)

undid well considered edit[edit]

I have undone a well considered edit. I am here offering what I regard as a justification for my undo.

I have some time ago carefully considered, as perhaps a suitable source for the present article, the book cited by the undone edit, <Čápek, V. and D.P. Sheehan, Challenges to the Second Law of Thermodynamics (Theory and Experiment); Vol. 146 in Fundamental Theories of Physics Series, (Springer, Dordrecht, Netherlands, 2005) ISBN: 1-4020-3015-0.> Perhaps I may add here a comment from the undone edit: "Most of these are theoretical and have little hope of being experimentally tested within the foreseeable future. Several have been resolved in favor of the second law; however, the majority still await experimental test or resolution."

My take on the proposed "challenges" is that they are not challenges to properly stated versions of the second law. They are challenges to various straw men, constructed to provide specious grounds for challenge. Many of them are about non-equilibrium scenarios, or about "entropy" for non-equilibrium systems. Such are not the province of strict statements of the second law, and so are not suitable to appear in the present article.

I do not wish to disparage the careful and diligent work of the editor whose edit I have undone. I am sorry that it may leave him feeling that his careful work has been rejected. It is that I think the properly stated second law is valid and reliable, and that the article should leave the reader in no doubt about that. I think it is possible to worry about the law, but that proper worries are more subtle than are captured in much literature.

It is not the aim of Wikipedia to present "mainstream" views. The aim is to find and report reliable sources.Chjoaygame (talk) 00:46, 1 March 2015 (UTC)

I am not expert enough to offer detailed comment on the merits of the deleted section written by Yusefghouth. However I am uncomfortable about completely removing what seem to be two well-written and balanced paragraphs with many references to leading refereed journals. Is there nothing at all of value in the deleted text?? If as I suspect it is partly correct, then the good parts should be of interest to readers of this article. Why not use the proposed text as a starting point, and try to correct any errors or misstatements?
For example you write above that Many of them are about non-equilibrium scenarios, or about "entropy" for non-equilibrium systems. Such are not the province of strict statements of the second law, and so are not suitable to appear in the present article. I would reply that there is no Wikipedia editorial policy which restricts the article to only equilibrium systems. Why not keep the section, and add a statement similar to your criticism, perhaps Many of them are about non-equilibrium scenarios, or about "entropy" for non-equilibrium systems. They are therefore usually considered as not the province of strict statements of the second law. This would have the merit of allowing each reader to decide whether s/he is interested in non-equilibrium systems.Dirac66 (talk) 02:53, 1 March 2015 (UTC)
I looked at the new edit before it was deleted and thought it should stay. I agree with Dirac66. It has now been restored. I suggest it is left while the matter is discussed further. It probably needs some changes but essentially it is worth stating. --Bduke (Discussion) 04:55, 1 March 2015 (UTC)

The edit that I undid, with a note "see talk page", has been restored by the editor who posted it, with an edit summary "please explain". I don't know if he read my above talk page justification, but he has not replied to it.

Editor Dirac66 asks is the edit entirely unsuitable for the article. He suggests using the edit as a starting point for new material. Editor Bduke concurs with that.

The arguments offered so far are that the edit is well referenced, and that it is open to question whether the law is about non-equilibrium scenarios.

I think that the edit is essentially misleading and ill-conceived, so that no amount of referencing could rescue it. I accept that it is supplied with relatively many references, but I counter that none of them deals with the real issues at stake, and that they therefore do not qualify as reliable sources for the purpose.

The key here is as I have written above, that the "challenges" are not true challenges to the law properly stated. They might be passed off as 'challenges' to faulty statements of the law, or as 'challenges' to various straw men. To earn a place in the article, proposed challenges should be much more critically and carefully thought out and constructed than are the remarks in the disputed edit. The disputed edit makes no attempt to deal with real issues and flaws in the proposed "challenges", and seems entirely unaware of what are those issues and real flaws. The disputed edit concedes that that there is incomplete experimental evidence for the "challenges", but that concession amounts to a petitio principii, assuming that the logical groundwork has been done that would make experimental checks relevant as genuine challenges worthy of the name. It is the lack of logical groundwork that is the reason why the edit is properly described as misleading and ill-conceived.

Editor Dirac66 proposes to offer the reader a personal choice about whether to consider non-equilibrium scenarios. I respectfully disagree. We are here concerned with one of the most respected laws of physics. There is no room for personal choice here. It would gravely mislead the reader to suggest that there is such room. If someone wishes to have more detail on this in the article, a suitable course of action would be to survey and analyse the literature on the theory of non-equilibrium scenarios and report on it. That is not remotely attempted by the disputed edit.

In a nutshell, the law is a law of classical thermodynamics. It is about processes that start and end with systems in their own respective states of internal thermodynamic equilibrium, in thermodynamic equilibrium with one another as allowed by the walls. The "challenges" do not address that law. To put them into the article would be to muddy that fact.

Many physicists would dearly love to think that the law is more general than the one just stated in the previous paragraph. Many physicists blithely assume that it is so. Then the proposed "challenges" might have some place in the article. But the law is not so. Those who wish to take it as being so need to establish their case, or to state some more general law, admitting non-equilibrium scenarios, and write an article about it. In effect, the edit represents wishful thinking, that the law be faulty, supported by flawed statements of it or wrong assumptions about what it means.

I am saying that disputed edit is hopelessly flawed and is not a suitable basis for a proposed section criticizing the law. I think Einstein is right about this. His considered opinion is not to be ignored. Classical thermodynamics, within its proper scope of applicability, will never be overthrown, however much some may wish to see it happen. To use the disputed edit as a basis for an addition to the article would be to invite an endless flow of drivel, with no compensating benefit.

The disputed edit should be entirely deleted. If someone wishes to challenge the second law in the article, they should do so with a fresh start, on a much better logical and structural base than the disputed edit.Chjoaygame (talk) 08:20, 1 March 2015 (UTC)

Editor Arthur Rubin has now deleted the edit in question a second time with the edit summary Well-referenced, but contradicted by even better references, so should not be here. Could we have the even better references please? Dirac66 (talk) 12:51, 1 March 2015 (UTC)
Actually, thinking it over, do we have reliable sources that the articles constitute "challenges" to the 2nd law? Even if the articles are peer-reviewed, this would require an independent reliable source. — Arthur Rubin (talk) 16:31, 1 March 2015 (UTC)

Editor Dirac66 is right to express concern about this matter. It is very important for the article. The bar is to be set high for this discussion. I do not expect that I can safely clear it, but I will offer something here. No source here is perfect, just as, present company excepted, nothing in the real world is perfect.

Callen, H.B. (1960/1985). Thermodynamics and an Introduction to Thermostatistics, (1st edition 1960) 2nd edition 1985, Wiley, New York, ISBN 0-471-86256-8, on p. 3 writes "The contrast between thermodynamics and its counterpart sciences raises fundamental questions which we shall address directly only in the final chapter. There we shall see that whereas thermodynamics is not based on a new and particular law of nature, it instead reflects a commonality or universal feature of all laws. In brief, thermodynamics is the study of the restrictions on the possible properties of matter that follow from the symmetry properties of the fundamental laws of physics."

This emphasizes that thermodynamics aims at generality. Consequently its scope is limited.

Callen also writes on page 5 "Perhaps the most striking feature of macroscopic matter is the incredible simplicity with which it can be characterized. We go to a pharmacy and request on liter of ethyl alcohol, and that meager specification is pragmatically sufficient. ... The pertinent few emerge as macroscopic coordinates, or “thermodynamic coordinates”."

And on page 6 "By definition, suggested by the nature of macroscopic observations, thermodynamics describes only static states of macroscopic systems."

And, shock of shocks, on page 15 he writes "In practice the criterion for equilibrium is circular. Operationally, a system is in an equilibrium state if its properties are consistenly described by thermodynamic theory!"

Also on page 15 "A description of a thermodynamic system requires the specification of the “walls” that separate it from the surroundings and that provide its boundary conditions."

Münster, A. (1970). Classical Thermodynamics, translated by E.S. Halberstadt, Wiley–Interscience, London writes on p. 52 "An isolated system is in thermodynamic equilibrium when, in the system, no changes of state are occurring at a measurable rate. ... The proviso 'at a measurable rate' implies that we can consider an equilibrium only with respect to specified processes and defined experimental conditions."

I will not continue along these lines because the question is so general and fundamental that my efforts can appear only as 'walls of text', the more the worse!Chjoaygame (talk) 17:25, 1 March 2015 (UTC)

outline[edit]

I am the author of the edit in question. I appreciate the civil and measured tone of these exchanges, something often lacking in discussions of this important law. I respectfully request that my edit be reinstated because the rationale for removing it is based on inaccurate information and an improper understanding of the second law. I would like to address what seem to be the principal concerns, specifically:

(A) The challenges are strawmen arguments.

(B) The challenges represent nonequilibrium systems to which the second law does not apply.

(C) It is unclear what the scope of the challenges are, whether they are classical or quantum, microscopic or macroscopic in nature; hence, whether the section should be retitled.

I will address these in order.Yusefghouth (talk) 21:49, 13 March 2015 (UTC)

(A) claim of straw men[edit]

The editor Chjoaygame's claim that these challenges are strawmen is a minority viewpoint, in fact, one that I've never seen before until I read his remarks. Furthermore, it seems at odds with a large body of evidence, namely, that these many challenges have been published by some of the best known scientific journals and presses in the world. The referees and editors of these 50-100 articles, monographs and conference proceedings apparently did not consider them strawmen, otherwise they would not have published them. Take one editor in particular, Gerard 't Hooft, Nobel laureate in physics and editor of Foundations of Physics. He oversaw the publication of the papers stemming from the 2006 AAAS symposium on second law challenges, published in Found. Phys. in 2007 (Reference 71 in the contested edit). He was also editor in 2014 when reference 85 was published, offering the first experimental evidence for second law breakdown in the laboratory. I don't understand why the reviews of so many editors and referees from so many good journals and scientific presses over the last 30 years have been brushed aside. Any additional light you can shed on this would be appreciated.Yusefghouth (talk) 21:49, 13 March 2015 (UTC)

There would be a huge payoff for anyone who could fault the second law. Such a person would outrank Clausius, Kelvin, Einstein. The Nobel Prize would be peanuts for such a person. So the incentive seems great.
Right here the objection is to my rhetorical term 'straw man', not to the real substance of my reasons. That others do not use the rhetorical label 'straw man' is not an answer to my argument.
My argument is that the proposed "challenges" are not challenges to the second law. They are falsely advertised. They are challenges to mis-statements or misunderstandings of the second law. There is a huge incentive to mis-state he second law, and correspondingly one must be very strict in demanding a correct statement. Weighty claims need weighty support. A faulty statement of the second law is not weighty support for anything.
So here I need to state the second law: "The second law of thermodynamics states that in a natural thermodynamic process, there is an increase in the sum of the entropies of the participating systems."
We need to talk physics here. This statement is about entropies of thermodynamic systems. Strictly speaking, a thermodynamic system has an entropy only when it is in a state of its own internal thermodynamic equilibrium. Many physicists would dearly love it not to be so. But they indulge themselves with wishful thinking. This immovable obstacle is not faced by the proposed "challenges", nor by the proposer of the 'challenge' section of the article. The question is not about whether the internal workings of a process means a temporary departure from thermodynamic equilibrium, as mistakenly in good faith suggested by the 'challenge' proposer. The equilibrium requirement is for the initial and final states of the process. This is what the second law refers to. It does not refer to the internal workings of the process. No amount of good faith or wishful thinking can change that.
What matters here is this argument, not whether one likes to label it a charge that straw men are being created.
Perhaps it may save time if I mention here the so-called 'entropy production' formulas of the 'local thermodynamic equilibrium' approximation. They make for good approximations for suitable problems, and are speciously labelled as if they refer to some kind of non-equilibrium "entropy". But they are not calculators of entropy strictly read. And here we need strict reading.
At the standard of reasoning needed to challenge the second law, to talk of entropy for non-equilibrium states one must define it. That has not been done. There is no real challenge offered here.Chjoaygame (talk) 00:12, 14 March 2015 (UTC)

(B) non-equilibrium question[edit]

It is claimed that these challenges are nonequilibrium systems to which the second law does not pertain. Actually, the second law applies to all thermodynamic systems, whether they are at equilibrium or not. In fact, it pertains especially to nonequilibrium ones. Take the Planck formulation: "The entropy change for any spontaneous process is never negative." A "spontaneous change" refers to a "nonequilibrium process." Or the Clausius formulation: "Heat flows from hot to cold, not vice versa." Again, a nonequilibrium process. In fact, many -- if not most -- formulations of the second law explicitly or implicitly invoke nonequilibrium. To assert otherwise is simply mistaken. These many challenges to the second law, by definition, require reversals of the normal direction of entropy change; therefore, they require nonequilibrium behavior at some point. To forbid noneqilibrium systems from discussion of the second law is not only mistaken in the physics, but also begs the conclusion.Yusefghouth (talk) 21:49, 13 March 2015 (UTC)

These remarks have been dealt with in sub-section (A). I do not wish to be harsh, but I have to say here that these remarks thoroughly misunderstand the physics. Such misunderstanding is widespread, and is supported by much wishful thinking.Chjoaygame (talk) 00:16, 14 March 2015 (UTC)

(C) eclectic set[edit]

The modern challenges cited in the edit are an eclectic set. Some are entirely classical in nature (e.g., gas-surface dynamics, solid state, biologically-inspired), while other are quantum mechanical (e.g., Capek's models, superconductor systems). They range in size from microscopic (molecular machines) to planetary in scale; their temperatures range from absolute zero up to the melting points of the refractory metals and ceramics. It is not accurate to call them purely classical or quantum, microscopic or macroscopic so I chose the term "modern challenges." I would be happy to expand the edit to make this point, but I believe it is implicit in the text already.Yusefghouth (talk) 21:49, 13 March 2015 (UTC)

That the set of "challenges" is eclectic is evidence of the range of misunderstandings of the second law, not an argument that any of them is a real challenge. One valid one would be enough.Chjoaygame (talk) 00:22, 14 March 2015 (UTC)

Summary[edit]

In summary, I do not believe the criticisms of my edit are reasonable grounds for its removal. Furthermore, I believe the edit adds new life to the important and healthy discussions begun more than a century ago by Loschmidt, Maxwell, Zermelo and other pioneers of thermodynamics. I respectfully request that my edit be reinstated. Yusefghouth (talk) 21:49, 13 March 2015 (UTC)

I hope this time I have done a better job of responding to your edit, giving persuasive or convincing reasons why it is wrong for this article. It is not that the details of your edit are lacking respectively their own merits in suitable contexts. It is that they are not real challenges to the second law.
It is not the purpose of the article on the second law to add life to discussions, however important and healthy they are.Chjoaygame (talk) 00:30, 14 March 2015 (UTC)

Better section title: Not Challenges but Quantum limits[edit]

Editor Arthur Rubin has questioned the use of the word challenges in the section title. The word appears to be based on the book title by Čápek and Sheehan (2005) also mentioned above by editor Chjoaygame, as well as on the title of the symposium proceedings edited by Sheehan (2011) - both are listed as references in the deleted section. For this article, perhaps a more acceptable section title would be Quantum limits to the second law, based on the title of an earlier conference proceedings in the same reference list also edited by Sheehan: First International Conference on Quantum Limits to the Second Law (2002). This would imply restricting the section to questions concerning very small systems, and exclude macroscopic systems. Dirac66 (talk) 17:37, 1 March 2015 (UTC)
Perhaps it seems unduly harsh to reject the proposed new material. The new material purports to "challenge" one of the most deeply accepted laws of physics. It has set the bar high for itself. The key is not, however, in the word 'challenge'. It is deeper than that. As a law of classical thermodynamics, the second law is about macroscopic systems. Some kinds of kinetic theory and statistical mechanics are about very small systems. To cover this by a change of title would be to move the goalposts during the game.Chjoaygame (talk) 19:52, 1 March 2015 (UTC)

undid well intentioned edit[edit]

I undid a well intentioned edit.

The article could be extended infinitely if it were to try to deal with the kind of matter submitted in the edit. That would be a bad path to open up.

The article is about the second law of thermodynamics, not about entropy production.Chjoaygame (talk) 22:38, 24 March 2015 (UTC)

Appearance of the word "field" and the phrase "force-field"[edit]

In the current version of the article word "field" appears 15 times in the lead, always in the context of a force field, and it appears twice in the body, never in the context of a force field. This is consistent with other science articles at Wikipedia where some well-meaning person with a lot of time on his or her hands takes ownership of an article and plops a lot of nonsense into the lead due to their own ignorance about how the topic is taught and used in the world outside of Wikipedia. Of course, force fields have little or nothing to do with the second law. Because Wikipedia's science content elsewhere is heading downhill so rapidly due to neglect from the knowledgeable and well-meaning nonsense from the ignorant, I recommend that the same level of force-field nonsense be added to the body of this article in order to hasten the process of making Wikipedia's science as blatantly silly as possible. Flying Jazz (talk) 16:31, 24 April 2015 (UTC)

One always feels flattered to have one's work praised, especially when it is done with such eloquence as just above. The requested detail on thermodynamic equilibrium in the presence of an external force-field is to be found here. I will post a link. It is true that not too many texts talk about the topic of present concern. But it is of interest to some readers.Chjoaygame (talk) 21:46, 24 April 2015 (UTC)
The comment that starts this section is not quite explicit as to what its author would like done. I have made a fair guess at that, and tried to accommodate.Chjoaygame (talk) 12:17, 25 April 2015 (UTC)
Perhaps I should have been more explicit then. Force fields have little or nothing to do with the second law. A good second law article would not mention them. That is why texts don't include it, and that may be why you included no references in the entire section you created. I hope you consider removing this silly content from this article in order to improve the encyclopedia. You would be accommodating the general reader if you did that. However, building a general encyclopedia may be about including things "of interest to some readers" in your mind instead of including things of interest to the general reader. You may hold the view that silly off-topic things are important, and, if you hold that pro-silly-nonsense opinion (because that's what some readers want), then I admire your persistence at advancing that opinion while simultaneously hoping that you stop holding that opinion and repair the damage done to this article. Science at Wikipedia is like a mound of rubble that used to be a half-finished building, and your accomplishment in this article is like a man standing on that mound smashing a single brick. In a way, I do admire that. But I'd prefer to have the brick back. Maybe that will help convince someone later to try to rebuild a bit of the building. Flying Jazz (talk) 03:08, 27 April 2015 (UTC)
Thank you for these comments. I have supplied references.Chjoaygame (talk) 04:41, 27 April 2015 (UTC)

Verification failure at [9][edit]

It is not enough to "supply references." The references must say what an editor claims they say. This means that Planck, Maxwell, Gibbs, etc. must have all provided support for the sentence "The various temperatures within the adiabatically separate component sub-systems become respectively spatially uniform." It does not mean that those famous people mention equilibrium or the second law in a context different from "adiabatically separate component sub-systems." I have checked that Planck on page 40 at [10] did not mention equilibrium in that context. I have checked that, while Maxwell mentions equilibrium over a dozen time in the treatise available at [11] he says nothing remotely similar to your claim about what he said. This is why all your references were removed. After checking two, I reached the conclusion that the others were also failures. Do not "supply references" that fail verification. Supply one, single, good reference that passes verification. Otherwise, you are a demonstrable liar about famous people, and you will most likely not gain support at Wikipedia by lying about famous scientists. Instead, people will call you names and you won't like it. Flying Jazz (talk) 06:03, 27 April 2015 (UTC)

Thank you for this comment. The references are to uniform temperature in adiabatically separate sub-systems. The Planck radiation reference says that regions in radiative exchange equilibrium have equal temperatures; this entails uniform temperature within a sub-system in thermodynamic equilibrium. I can now see that you want to take a position against the material I posted, and so I will not go further here. Your concern is about immediacy of context. I have looked at the reference you gave. I think it is consistent with what I posted and you have deleted. From your bolding, I infer that you have strong feelings here. Like you, I do not engage in edit wars, so I will not resist you in this.Chjoaygame (talk) 07:26, 27 April 2015 (UTC)
Though I do not intend to edit war, I think it reasonable that I comment more on your edit, with its edit summary "Entire section deals with work terms in combined first/second law. Not second law material."
You deleted text that was worded with the specific intent to exclude the case that I think your edit summary refers to. The work referred to in your citation is about transfer of matter into or out of the system of interest. You deleted a section that was worded with the specific intent of excluding that case. I am not sure whether you took that into account. Perhaps my wording did not succeed in making the exclusion clear. If it did not succeed, that would be a failure of execution not of intent.
In more detail, the table on the page to which you refer lists a differential quantity ψdm = ΣghMidni. The term dni identifies the quantity as a transfer of matter into or out of the system of interest, deliberately excluded by the way I worded the deleted section. Work done by the external-field imposing factor was excluded also by forbidding motion of the centre of gravity of the system of interest with respect to the external-field imposer. The internal energy of the system of interest is distinct from its global potential energy and its global kinetic energy. So your concern that I was mixing first and second laws seems to need reconsideration. I don't think I was doing so. I concede that during the process of making the section, at first I did not succeed in excluding work by the field-imposer, but I did restrict it to work that altered the kinetic energy of the system as a whole. On thinking about that I saw that all forms of work needed exclusion for the narrow statement that I intended, because it is hard to assign an entropy related to the kinetic energy of the system as a whole. My aim was not to make the statement completely general and capable of dealing with every case. It was to make a narrow statement that allowed an externally imposed field to persist during the process, thus making it clear that such a field would not, through the law, create a temperature gradient at final equilibrium due to the field.Chjoaygame (talk) 08:34, 27 April 2015 (UTC)
The reader of a general purpose encyclopedia is best served by clear, focused, well-referenced, and verifiably correct material. Editor aims or what an editor is thinking about outside the context of serving that general reader are misguided. There are an infinite number of "narrow statements" that do or do not violate thermodynamic laws. If some of those statements are to be included in a second-law article then consideration for a general reader dictates that only the simplest and only the most second-law-focused out of that infinite number of possibilities will be chosen by an editor. That same consideration for the general reader also applies to talk page discussion which is why I won't be attempting to parse the remainder of what you've written above about "kinetic energy of the system as a whole" and "field-imposers" and such things. Flying Jazz (talk) 13:25, 27 April 2015 (UTC)

sources[edit]

The verification of references is important. The reference to Maxwell is to his pages 86 and 87. On page 86 he writes "A vertical column would therefore, when in thermal equilibrium, have the same temperature throughout." I was led to this source by Bailyn on his page 254 "As for temperature, it is interesting to note that Loschmidt in 1875, the year after Gibbs' paper, suggested that temperature should vary with height, and that Maxwell's statistical mechanics could not be completely correct since it did not show this (J. Loschmidt, Sitz. Wien. Acad. 73, 139 (1876)). Boltzmann soon clarified the situation in statistical mechanics, but even before this, Gibbs had shown from his thermodynamic principles that temperature should be uniform (J.W. Gibbs, Scientific Papers of J.W. Gibbs, Vol. 1, (Dover Publications, New York, 1961), pp. 144–150.)." I will not go further here, since it seems you drew your conclusion without actually checking the remaining references, but guessed that they were faulty from your glance at the Maxwell reference. I concede that the Planck reference was simply to radiative exchange equilibrium, and did not explicitly mention the temperatures, which have to be equal by the zeroth law, and Planck's general principle of homogeneity in thermodynamic equilibrium.Chjoaygame (talk) 17:16, 28 April 2015 (UTC)

The relevance of the Planck reference is that although the top and the bottom of a columnar compartment are not in immediate conductive contact, they are in radiative exchange equilibrium. The zeroth law has no exception for the presence of a force field.Chjoaygame (talk) 19:11, 30 April 2015 (UTC)

On further consideration, I think it may be useful that I here give some more information about the list of sources under discussion.

On page 144, Gibbs heads a section "The Conditions of Equilibrium for Heterogeneous Masses under the Influence of Gravity". He writes on pages 144 and 145 "Let us now seek the conditions of equilibrium for a mass of various kinds of matter subject to the influence of gravity. ... The energy of the mass will now consist of two parts, one of which depends upon its intrinsic nature and state, and the other upon its position in space. ... From (225) we may derive the condition of thermal equilibrium,

t = const.                                                (228)"

Gibbs' t denotes temperature.

On page 143 Boltzmann in translation writes "... the temperature is also the same everywhere, in spite of the action of the external forces."

On page 75, Chapman and Cowling start a section entitled "The steady state in the presence of external forces". In that section they write on page 77 "This result was first given by Maxwell (J.C. Maxwell, Nature, Lond., 8, 537 (1873); Collected Papers, 2, 351.) as a deduction from his equation (4.1, 5). Boltzmann (L. Boltzmann, Wien. Ber. 72, 427 (1875).) later gave the same result ..."Chjoaygame (talk) 02:41, 1 May 2015 (UTC)

Ter Haar and Wergeland's Chapter 9 on 'Systems in External Fields' notes on page 128 that "We will find that at equilibrium, T(x, y, z) must be constant over V, ..." They use the fact that "Here “energy” must be understood as the total energy: E = internal energy plus potential energy of the system in the external field."Chjoaygame (talk) 07:35, 1 May 2015 (UTC)

Recommendation for new Gravothermal effect article[edit]

The verification of references is important to serve the general reader of a particular article. The verification of references in order to address editors who show up in the talk page space is less important. In the talk page there is some issue about a "gravithermal effect" or "gravothermal effect." Here's what's written in the introduction to Alberty's IUPAC paper at [12]:

In addition to the terms from the combined first and second laws for a system involving PV work, the fundamental equation for the internal energy may involve terms for chemical work, gravitational work, work of electric transport, elongation work, surface work, work of electric and magnetic polarization, and other kinds of work.

Alberty's paper explicitly spells out IUPAC-supported nomenclature and terminology. It also conforms with my own impression of the second-law curriculum of a general science and engineering education. In general thermodynamics, gravity and other "external force fields" are added on to the first-law part of the combined first and second laws as additional work terms, and what's permitted or forbidden can be determined after that's done. To me, this means that there is no sound reason to include any section dealing with gravity (or electricity or elasticity etc.) in a general-purpose encyclopedia article about the second law. When editors argue with each other, irrelevant matters start to seem important, and the reader often pays the price by having an article with a huge amount of off-topic or tangential things in it. That doesn't mean either that the possibility or impossibility of a gravothermal effect is irrelevant in a broader sense. It might be important in fields where I lack expertise, like astrophysics. Maybe tidal work is also relevant to astrophysics as another work-term addition to a combined first-and-second law. I don't know. But I do think, based on Alberty's most-common nomenclature, that gravitational systems and/or "external force field" stuff don't belong in their own sections in a Second Law article. It might be a good idea for you and the people you've been arguing with to begin a new Gravothermal effect article explaining what it is and why it's real or not real and how it is or isn't involved with astrophysics or other fields. Gibbs was brilliant, but I don't think he considered what astrophysicists today consider because they have the advantage of building upon his brilliant foundation. But I honestly don't know. On that new Gravothermal effect article talk page, you and the various IP addresses and editors with whom you've been arguing can present focused article-specific arguments that may serve the reader of that new article. Flying Jazz (talk) 20:34, 4 May 2015 (UTC)

Thank you for this comment. Though it might seem straightforward and simple enough, your comment raises some important but rather subtle questions. At this minute I have other activities scheduled. I will try to reply later.Chjoaygame (talk) 00:45, 5 May 2015 (UTC)
I have now carefully considered what you propose. At present I think it would be inappropriate.Chjoaygame (talk) 06:13, 5 May 2015 (UTC)
Of course you think a Gravothermal effect article would be inappropriate. That's because you seem to think the effect doesn't exists at all because the combined first and second law forbids it after the appropriate terms are inserted into the combined first and second law. My comment was for those other folks who think it does exist. They're the ones who should start the new article. You should follow them over there, argue with them over there, and try to come up with an article that serves the reader over there. After a while, someone might stop by here (maybe even me when I have more time) and serve the reader by repairing the damage that was done by the inappropriate insertion of elements of that argument about the combined-first-and-second-law-with-additions into this article about the second law. Flying Jazz (talk) 13:59, 5 May 2015 (UTC)
Near enough, the present concerns are non-relativistic, not even special relativity. Consideration of gravothermal effects belongs to general relativity. I am reasonably confident the the "several" "folks" are just one.Chjoaygame (talk) 14:26, 5 May 2015 (UTC)Chjoaygame (talk) 23:29, 5 May 2015 (UTC)

Externally imposed fields[edit]

It may be useful to comment here on some aspects of externally imposed fields. The above mentioned 2001 Committee report written by Alberty refers to a 1994 paper by him.[1] This paper for gravity refers on page 1470 mainly to two admirable texts, by Guggenheim[2] and by Kirkwood & Oppenheim[3] In considering external fields, neither of these texts refers directly to the founding work by Maxwell, Gibbs, or Boltzmann. In considering a tall column in a gravitational field, Guggenheim contents himself on page 5 with the phrase "the temperature, assumed uniform". Kirkwood & Oppenheim are content to use a single temperature without even mentioning that it is so by assumption.

There are some points that need attention, and are to some extent dealt with by Alberty, by Guggenheim, and by Kirkwood & Oppenheim.

  1. In a gravity field, it is often necessary to represent the column as consisting of infinitely many infinitesimally thin-layer systems stacked contiguously.
  2. Gravity fields differ from electric fields in that usually the column in a tube is not heavy enough to significantly alter the earth's gravitational field inside the tube, whereas electric polarization is often significant for relevant electric fields. Besides work of electric transport, the electric field can interact through polarization with chemical reaction in a way that the gravity field does not.
  3. The total energy of a body is the sum of its internal energy, and respectively its potential and kinetic energies as a whole by virtue of the position and velocity of its centre of force in the external field.
  4. If a body moves as a whole due to gravity, it may thereby simply suffer a change in its kinetic energy as a whole, with no change in its internal energy.
  5. It can happen, however, that a part of the system, such as for example a suspended weight, moves due to gravity to a lower place within the system, while another part of the system, such as for example some paddles, is thereby set in motion within the system and thereby gains kinetic energy, which is then by friction dissipated and converted to internal energy within the system. Then gravity has done isochoric work on the system and increased its internal energy, at the same time lowering its centre of gravity. Of its total energy, the internal moiety has increased precisely at the expense of the potential moiety.

References

  1. ^ Alberty, R.A. (1994). Legendre transforms in chemical thermodynamics, Chemical Reviews, 94 (6): 1457–1482.
  2. ^ Guggenheim, E.A. (1949/1967). Thermodynamics. An Advanced Treatment for Chemists and Physicists, (1st edition 1949) 5th edition 1967, North-Holland, Amsterdam.
  3. ^ Kirkwood, J. G., Oppenheim, I. (1961). Chemical Thermodynamics, McGraw-Hill Book Company, New York.

Chjoaygame (talk) 18:01, 11 May 2015 (UTC)Chjoaygame (talk) 20:39, 17 May 2015 (UTC)Chjoaygame (talk) 02:42, 27 May 2015 (UTC)

Possible intent of Chjoaygame[edit]

I believe what this editor meant to say is covered by the combined first and second law in the context of gravitational work as discussed by Alberty in Table 1 on page 1357 at [13]. Other entities that you call "force fields" are also mentioned in that table and discussed in their proper thermodynamic terms in that article. Because this material is more appropriately discussed in the context of the combined first and second law, it is inappropriate for an encyclopedia article on the second law. That is my rationale for removing the entire section of the article dealing with "externally imposed force fields." Flying Jazz (talk) 06:08, 27 April 2015 (UTC)

My intent was to make it clear that the second law cannot be used to justify the mistaken claim that a system in its own internal state of thermodynamic equilibrium, in the presence of a gravitational or other field, has a temperature gradient established by the field. There is no such temperature gradient established through the effect of the second law or otherwise. That is what my references supported.Chjoaygame (talk) 07:54, 27 April 2015 (UTC)
I haven't been following the history of this article for years, so perhaps another editor claimed in the article that such things could happen, and so your intent was to claim in the article that such things could not happen. An infinite number of ridiculous things can be said ,disputed, and corrected, but the article space is not the place for that to happen. In the article, only the simplest of claims about the thermodynamic certainty/possibility/impossibility of processes serve the general reader. Those simplest of claims were the ones discussed by the founders of thermodynamics, and they are most likely already included in the article multiple times. Flying Jazz (talk) 13:39, 27 April 2015 (UTC)

Possible future actions regarding references that failed verification[edit]

I do not wish to engage in an edit war. If you persist in adding failed references to this article, it will be tagged as such with the appropriate template and delivered to Category:All_articles_with_failed_verification. If you remove the template, I will attempt to replace it once, and if you remove the template a second time, I will complain to some adcom or arbmin clerk type person for the first time since I joined Wikipedia in 2005. There's a first time for everything. Lying about famous scientists to support silliness is the one thing that will push my buttons. Flying Jazz (talk) 06:14, 27 April 2015 (UTC)

Confusion regarding "system" and "process"[edit]

About three or four years ago Wikipedia explained the Second Law like this: “An isolated system, if not already in its state of thermodynamic equilibrium, spontaneously evolves towards it. Thermodynamic equilibrium has the greatest entropy amongst the states accessible to the system.” That was good. The current statement “The second law of thermodynamics states that in a natural thermodynamic process, there is an increase in the sum of the entropies of the participating systems" implies that there are "systems" within the single process referred to. In fact, the law is about a process that happens within a single isolated system. If there is more than one process, then such processes must be dependent, not independent. So, in effect, a sequence of dependent processes is just a single process anyway. What you need to understand is that the Second Law is describing what happens in nature when there are unbalanced energy potentials. Such unbalanced energy potentials autonomously tend towards the state of balance, and this happens by the fastest possible route. That state of thermodynamic equilibrium has maximum entropy and no remaining unbalanced energy potentials. That is the Second Law of Thermodynamics, which is not just about heat and temperatures, because entropy can involve all forms of energy. Douglas Cotton 58.164.63.3 (talk) 11:41, 25 April 2015 (UTC)

I agree with most (but not all) of your first few sentences, and agreement in talk pages has been rare for me lately. But, unfortunately, your last few sentences head out toward left field. There is a quibble about a second law definition for isolated systems (entropy reaches a maximum at equilibrium) versus closed adiabatic systems (work interactions are possible, so entropy increases but it might not reach a maximum). You can read my old talk page babble about that quibble at Talk:Second_law_of_thermodynamics/Archive_2#Rigor_about_isolated_vs_closed_adiabatic. But, as often happens, I didn't cobble a consensus from the rabble by dabbling in babbling quibbles. Mentioning that distinction for closed adiabatic systems probably wasn't appropriate for the lead anyway. The people arguing with me had my respect back then (They weren't really a rabble.), and they made some good points. Consensus was reached, and the result was an article where adiabatic closed systems weren't mentioned once. But, as usual, German Wikipedia ended up agreeing with me because they do science better over there. If you head over to [14], you'll see "In einem geschlossenen adiabaten System kann die Entropie nicht abnehmen, sie nimmt in der Regel zu." I also agree that multiple processes are best regarded as a single process. As long as all subprocesses fall within system boundaries, the second law applies to the entire process. And I also agree that discussing a compound anything (system or process) in the lead would be a mistake. However, the concept of unbalanced energy potentials is just as silly as all that silly force field stuff. Alas, the silliness cannot be avoided in science at English Wikipedia in the long term. It just becomes a matter of stamina about which silly editor sticks around to get the silliest material in, and removing their silliness just makes the silly people mad. The times of respectful consensus were short. After google translate improves, the science articles at German or Swedish Wikipedia may become useful for English speakers. Until then, why not try to convince Chjoaygame about unbalanced energy potentials? And he can try to convince you about force fields. I'll watch. Flying Jazz (talk) 04:14, 27 April 2015 (UTC)

section headed "Gravitational systems"[edit]

I would like to delete the sub-section of this article that is headed Gravitational systems.

In defence of the sub-section it might be proposed that it contains interesting and important material, or that it is well written. It may be so, but I say that is not an adequate reason to make this article the one that presents it.

Against the sub-section's appearing in this article, I think there are weighty reasons. The sub-section is mostly about essentially non-equilibrium scenarios, with a good dose of general relativistic considerations. The second law, however, is a law of classical thermodynamics, about processes that have initial and final states in thermodynamic equilibrium. Gravity on a small scale is within the scope of classical thermodynamics, but it is hardly so for large-scale systems that show great changes in the gravitational field during the "process", which is often not even from one state of thermodynamic equilibrium to another. It may be exciting to talk about large-scale systems, but it is not the province of standard texts on classical thermodynamics.

If it is desired to tell in Wikipedia about questions that are raised in the sub-section, then I think it should be told in a separate article.Chjoaygame (talk) 15:40, 23 May 2015 (UTC)

I tend to agree that this sub-section is off-topic and should be in a separate article. Perhaps a new article on Relativistic thermodynamics which could also include the present article on Relativistic heat conduction. Yes, I know that article is about special relativity, but the article could perhaps include Thermodynamics in special relativity, Thermodynamics and general relativity, and also Applications in astrophysics. Dirac66 (talk) 01:11, 25 May 2015 (UTC)
Thank you for this comment. I am not clued up enough to try to say how the material should be presented in some other article. I think simple deletion from this one would be ok. If someone is expert and energetic enough to put it up again in a more suitable article, that would be good.Chjoaygame (talk) 06:49, 26 May 2015 (UTC)