Talk:Second law of thermodynamics/Archive 3

message: Isn't the idea of heat being a physical substance called caloric a debunked theory? Is the current understanding of the 2nd law of thermodynamics still based on this obsolete theory? Should it be noted that mainstream science no longer considers caloric a valid model of thermodynamics?--Subversive Sound (talk) 16:07, 10 August 2009 (UTC)
replies: text: Indeed, heat is not a physical substance, if by "substance" we mean collections of molecules. However, none of the laws of thermodynamics require considering heat a physical substance. David spector (talk) 22:17, 26 December 2009 (UTC)
thread_title:  Caloric Theory 

message: A few years ago I spent considerable time analyzing natural ambient temperature fluctuations on a macro scale by means of two thermistors and an appropriate amplifier. Each thermistors was ~ 1mm in length. Regardless of how well the system was insulated there were always thermal fluctuations. On a nanoscopic scale it is a violent world where particles are in random rapid motion. Regardless of sample duration, temperature in any closed system will vary from measurement to measurement. One interesting universal effect is 1/f noise (also referred to as Pink_noise, Occurrences) where the noise (in this case temperature fluctuations) is relative to the reciprocal of frequency. The 1/f noise alone prevents consistent measurements regardless of sample duration. Another interesting study in terms of 2LoT is the Universe where one region of space is cold while another is hot such as our Sun. One may suggest the Universe is not yet at equilibrium, but then such a question becomes meaningless when asked at what point in time would the Universe be at 100.0...0% equilibrium.--PaulLowrance (talk) 16:52, 12 July 2008 (UTC)
replies: text: Please reserve this space for discussion of potential improvements to the article. General discussion of the topic itself is not appropriate. - Eldereft (cont.) 21:30, 12 July 2008 (UTC)
replies: text:  The obvious point is the article makes various references to equilibrium when such a state is impossible. The article should make that clear.--PaulLowrance (talk) 23:25, 12 July 2008 (UTC)
replies: text:  The article already says "the second law applies only to macroscopic systems with well-defined temperatures." That means that if you only view the "nanoscopic" as "reality", then thermodynamic equilibrium is not "real." It's just an oversimplified bulk generalization. However (fortunately, I think) human beings are larger than a millimeter shortly after conception, and we don't have the sensitivity of an amplified thermistor, so equilibrium makes a lot of sense to us out here in our larger world. It's a useful concept to us big people who read Wikipedia. Maybe you will be able to understand us someday, millimeter-man. Flying Jazz (talk) 13:36, 4 August 2008 (UTC)
replies: text:  I agree thermodynamic equilibrium is an oversimplified bulk generalization. On a scale of say the size of an apple objects appear to be stable as far as the human eye's concerned, but take for example Brownian motion on particles that the unaided human eye can barely detect such as a grain of pollen. Anyone with a good magnifying glass can see such particles jittering around on water at room temperatures, even inside the best isolated chambers. In fact it was such pollen that helped confirm the existence of the atom-- reference: Einstein's 1905 paper. Such Brownian motion that occurs at macro scales always exists due to the natural ambient thermal energy. My point is that thermodynamic equilibrium does not exist at any scale. The Universe is in constant change. Even the Earth's spin that causes daily temperature fluctuations between night and day will affect the best insulated systems to some degree, as it would require infinite insulation. It would nice if the wiki article included a section on how the mathematical thermodynamic equilibrium is an impossible state. --PaulLowrance (talk) 18:08, 8 August 2008 (UTC)
replies: text:  I agree with PaulLowrance. I know next to nothing about thermodynamics, but already reading his comments has confirmed some thoughts I had been formulating after reading the article.  --203.55.211.33 (talk) 04:37, 7 January 2009 (UTC)
thread_title:  No such thing as [[Thermodynamic_equilibrium|equilibrium]] under real conditions. 

message: The section concerning the sun is largely irrelevant to this article.67.163.246.108 (talk) 05:40, 15 July 2008 (UTC)
replies: text: The example is cited fairly regularly in second law contexts (I think my thermodynamics course put it between solar flux received by Earth and before degenerate white dwarves). I believe that its purpose here is as a material demonstration that figuring out how the second law holds can be fairly subtle. - Eldereft (cont.) 10:28, 15 July 2008 (UTC)
replies: text: In any case, the section does not describe how the second law holds. As it is written, it seems fairly irrelevant. I think this section should be deleted. Jacob2718 (talk) 14:20, 11 September 2008 (UTC)
thread_title: The Sun

message: The figure of 1kW/m² of at the sun's surface is surely wrong. This is the approximate value of the sun's energy at the surface of the earth, not the sun.
Jdpipe (talk) 05:12, 19 July 2008 (UTC)
thread_title: Dubious

message: I deleted the section discussing heat transport in the sun. At first glance, there are several situations where the second law appears not to hold (a refrigerator!) and I don't think this is the right place to discuss all of them. If the issue is historical i.e if this was historically proposed as a violation of the second law, maybe we can include that but only if the appropriate historical references are added. Jacob2718 (talk) 14:26, 11 September 2008 (UTC)
thread_title:  Section on the Sun  

message: Let me state just two strange things that, to me, seem to be implied by the second law of thermodynamics:
If I run either my (1) refrigerator or my (2) air-conditioning for an extended period of time (BILLIONS of years), what would happen? Entropy? Or does the law enable me to keep running my fridge and AC forever? 97.103.81.29 (talk) 18:16, 2 November 2008 (UTC)
replies: text: Anything you do will increase the total entropy of the universe. In this case you would get an astronomical electric bill and help accelerate the heat death of the universe! --Itub (talk) 09:24, 4 November 2008 (UTC)

text: One consequence of the Second Law is that you can't run a refrigerator or air conditioning without an external power source: if you ran them for billions of years, your external power source would run out. On a related note, I was living in Paris during the 2003 European heat wave, when temperatures reached 44 ºC (112 ºF)… at the time, French newspapers ran commentaries on the Second Law, reminding people that keeping the fridge door open was a very expensive way of making the room even hotter! Physchim62 (talk) 21:39, 4 November 2008 (UTC)
thread_title:  Entropy? 

message: The 2nd law of thermodynamics states, in certain way, that all physical laws' information tend to dispersion, to deaccumulation, and, in this sense, all physical laws tend to dissipation and minimization.
But, the 2nd law of thermodynamics, is also another physical law.
So, how can the 2nd law of thermodynamics "dissipate" and "minimize" itself? (in certain sense, 2nd law of thermodynamics states that physical laws are false)
(PS: btw, if there's a time arrow, then there's an arrow; and if there's an arrow, then there's order and information.) --Faustnh (talk) 14:47, 5 April 2009 (UTC)
replies: text: At the heat death of the universe, it will no longer be possible to observe if the Second Law is true or not! Physchim62 (talk) 15:29, 5 April 2009 (UTC)

text: The second law does not state, "all physical laws' information tend to dispersion". It states that isolated physical systems tend to disorder. The second law does not apply to Newtonian mechanics, for example, a set of laws that describe everyday physical force and motion almost perfectly. It also does not apply to Brewster's Law or any other. It does not apply to itself. It applies only to isolated thermodynamic systems.
The laws of physics have all been verified through experimentation, observation, and the consistency of a large body of theoretical reasoning based on them. If you feel that a law of physics is incorrect, paradoxical, or has some other such flaw, you may simply not understand the particular law. In such a case, a WP article may need to be clarified to help remove the possibility of the misunderstanding.
My own opinion: just because some WP articles may be too advanced for a casual reader to understand is no justification to claim that such an article is incorrect. People reading WP are expected to be educated enough to understand the scope of any article. On the other hand, WP articles should be written as clearly and completely as possible within a reasonable amount of space. David spector (talk) 23:29, 26 December 2009 (UTC)
thread_title:  On An apparent paradox about the 2nd law of thermodynamics 

message: Hi, I'm considering another special question about this physical law:
If the Universe doesn't suffer losses, then how come the 2nd law can be fulfilled at universal scale? (The second law bases on radiation arrow of energy; what happens when this arrow meets the border of Universe? should it reverse somehow? And if the Universe is a borderless sphere, what implications should this have with respect to that arrow?) --Faustnh (talk) 22:23, 8 May 2009 (UTC)
replies: text: See WP:TALK: this page is for discussing improvements to the article, based on verifiable sources, not your original research. If you want to blether or get all existential, follow the arrow elsewhere. . . dave souza, talk 23:48, 8 May 2009 (UTC)

text: I agree with Dave Souza's comment, but I would have expressed it far more politely and gently. Foustnh is clearly sincere and interested in a discussion exploring implications of the second law of thermodynamics. Unfortunately, WP, as Souza points out in an unnecessarily rude way, is an encyclopedia of information, not a discussion forum. David spector (talk) 23:33, 26 December 2009 (UTC)
thread_title:  On another strange question about the 2nd law of thermodynamics 

message: I've gone ahead and deleted the following miscellany. None of it serves to improve the article.
* Flanders and Swann produced a setting of a statement of the Second Law of Thermodynamics to music, called "First and Second Law". 
* The economist Nicholas Georgescu-Roegen showed the significance of the Entropy Law in the field of economics (see his work The Entropy Law and the Economic Process (1971), Harvard University Press).
* Creationist Duane Gish incorrectly used the Second Law of Thermodynamics to argue that evolution was impossible, although stand-up comedian Dave Gorman has pointed out that Gish misunderstood the definition of a closed system.
* The Last Question, a science fiction short story by Isaac Asimov, is centered around the question of how to reverse the Second Law of Thermodynamics, or entropy.
* One of acclaimed comic writer Alan Moore's short stories, chronicled in a collection called Wild Worlds, depicts indestructible and/or immortal characters facing down the unstoppable entropy at the end of the universe.
Chemeditor (talk) 19:32, 11 October 2009 (UTC)
replies: text: IMO, these items deserve to be moved somewhere where they can be preserved and found. Although they are less WP:Notable (or important) to be included in WP, they do appear to be true and clearly relevant for some WP users. David spector (talk) 23:44, 26 December 2009 (UTC)
thread_title: Miscellany

message: Worth mentioning?
* http://link.aps.org/doi/10.1103/PhysRevLett.103.080401
* http://arxiv.org/abs/0802.0438
--Dc987 (talk) 07:40, 8 December 2009 (UTC)
replies: text: Yes, but then this article has already been criticized, so we need to then mention the criticism also... Count Iblis (talk) 15:10, 8 December 2009 (UTC)
replies: text: Where can I find it? I've only seen a few comments on the blogs. --Dc987 (talk) 19:52, 8 December 2009 (UTC)
replies: text:  arXiv:0909.1726, arXiv:0911.2610, arXiv:0912.1947 Hweimer (talk) 15:12, 4 February 2010 (UTC)
thread_title:  QM derivation 

message: When we speak of heat traveling in the form of radiation it seems to me we are really talking about net heat. As I understand it, two bodies of different temperatures are both radiating heat. The net effect is for the cooler body to warm up and wamer body to cool down, but heat travels from the cooler body to the warmer body at the same time heat travels from the warmer to the cooler body. The net effect does not contradict the 2nd law but in the process, heat is traveling from cooler to hotter. Jojalozzo 13:58, 2 May 2010 (UTC)
replies: text: If in a vacuum, you had a microscopic, hot body separated 1 millimeter from cooler heat lamps surrounding at all angles, may be possible that heat can flow from cold to hot, and the reason is while the heat flux density of the cooler lamps is by definition lower than that of the hotter body, the effective area of radiation reduces as the heat from the heat lamps concentrates toward the center. Therefore, if the lamps are not too cold, it is conceivable that the heat flux from the lamps may be concentrated at the microscopic body, resulting in a heat flux density higher than the hot body, thereby warming it up.Kmarinas86 (6sin8karma) 19:28, 2 May 2010 (UTC)

text: A macroscopic example is an array of reflectors set to point at a particular spot, such as the PS10 solar power tower, where it is evident that heat in the form of radiation is reflected by the cooler solar reflectors into a spot that is heated to 285 degrees centigrade.Kmarinas86 (6sin8karma) 19:37, 2 May 2010 (UTC)
thread_title:  Heat radiation 

message: The rules for editing and writing encyclopedia entries require the knowledge to be verifiable (ie true as far as possible to determine) and stated with clarity. Which excludes philosophical speculation.. reference to the 'equal a priori probability postulate to the future' have no relevance to the introduction of this topic, is unclear and inadequately referenced.
Vh mby (talk) 03:53, 31 May 2010 (UTC)
thread_title:  Introduction 

message: Shouldn't the equations containing "log" be changed to "ln" so that they don't get confused with logarithm of base 10? Compare with, for example, the entropy article. /Natox (talk) 07:56, 4 June 2010 (UTC)
thread_title:  log vs. ln 

message: Under the definition proposed by Lord Kelvin, the statement:
"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)."
Is unclear at best, and incorrect at worst. If the phrase it accurate, it needs supporting explanation to justify the claim. Infrared and visible light are the same thing, just at different frequencies. Why then would it be necessary to consider the other side of the panel in one case but not the other? Perhaps the statement assumes that the hypothetical solar panel works off the net IR radiation, in which the radiation from the panel must be subtracted from the incoming radiation.
I personally don't see the relevance of this statement and suggest it be deleted. 65.112.42.84 (talk) 20:34, 24 June 2010 (UTC)
replies: text: Well, it certainly needs clarification, but there is a grain of truth in there somewhere. At a temperature of, say, 3000 K, black body radiation is well into the visible. So its like saying you cant have a solar panel at 3000 K that generates electricity from the visible without at least worrying about a temperature gradient. If there is no temperature gradient, then the solar panel will be acting like a black body in the visible, emitting as many visible photons as it absorbs, whatever the mechanism, and there won't be any net gain of energy. PAR (talk) 00:44, 25 June 2010 (UTC)
thread_title:  Proposed deletion 

message: In nuclear fusion, matter is converted into energy which means energy CAN be created and contradicts the second law.  —Preceding unsigned comment added by 88.106.65.159 (talk) 11:51, 27 June 2010 (UTC)
replies: text: I think you mean first law.  And, no, energy is not created. --Michael C. Price talk 23:58, 28 September 2010 (UTC)

text: Actually there is a mass loss in nuclear fusion, the masses of the products are less than the mass of the reactants, but in relativity, the first law would be re-expressed as a law of conservation of mass/energy. PAR (talk) 02:13, 29 September 2010 (UTC)

text: Its not so bad. Which is a better statement: "space is converted to time" when you change inertial systems, or "space is a form of time"?. I think the first statement is better, and "matter is converted into energy" is better than "matter is a form of energy". Just like space and time, the distinction between matter and kinetic or potential energy is clear for a given reference frame. Its when you change reference frames that one loses and the other gains. Even in the same reference frame when the change is due to say, a fusion reaction, the distinction is clear before and after. PAR (talk) 02:52, 30 September 2010 (UTC)
replies: text: Energy cannot be created or destroyed. Only transformed. You miss the point of nomenclature. Good nomenclature has less to do with what words or phrases sound like and more to do with what they appear to mean. Statements like "matter is converted into energy" give the impression that any process involving the "release of energy from mass" violates the first law of thermodynamics. Mass can be considered as a form of internal energy, and it can be easily taken into account in thermodynamic systems.Kmarinas86 (6sin8karma) 04:59, 30 September 2010 (UTC)
thread_title:  Nuclear Fusion contradicts Thermodynamics 

message: Non -isolated systems section:
Also, John Ross writes:[11]
    Ordinarily the second law is stated for isolated systems, but the second law applies equally well to open systems.
Applications section:  Furthermore, the second law is only true of closed systems. 
It's a long article and I suspect these aren't the only things that don't match up.  therefore I recommend a complete rewrite by an expert or whatever 131.151.90.125 (talk) 08:49, 28 July 2010 (UTC)
replies: text: It would be most appropriate to see a mathematical example which would indicate the validity of this statement by John Ross.Kmarinas86 (6sin8karma) 00:07, 29 July 2010 (UTC)
thread_title:  Contradiciton within the article

message: This article is not only self-contradictory,but also poorly organized.I suggest to rewrite it into these parts(not the names of sections,just the content):
#Kelvin and Clausius form of the Theorem and their equivalence
#Carnot's theroem and Perpetual motion of the second kind
#Clausius' inequality
#Introduction and the well-definity of Entropy and the mathematical form of the Theorem
#Available useful work
#Several so-called "paradoxes" of the Theorem(like Maxwell's Demon,Gibbs paradox)
#Self-organisation and life
#Derivation by stastical mechanics
#Unresolved problems(time arrow,and the heat death of the universe)
I have no idea where to put the "History" section and perhaps an independent section containing all the common misinterpretations of the Theorem will be useful.
--Netheril96 (talk) 13:54, 2 October 2010 (UTC)
thread_title: Rewriting the article

message: 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! 
*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. 
*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."  
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..   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)
replies: text: 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)
replies: text: This was just meant as a "heads-up".   Will Beback  talk   19:41, 15 November 2010 (UTC)
thread_title:  LaRouche 

message: 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)
thread_title:  Clausius-Mussoti etc. 

message: "...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.
(This was last edited on 19 December 2012. It lacks a time of editing label and I think has therefore eluded the usual archiving process. Time to archive it, I think.Chjoaygame (talk) 06:54, 21 November 2015 (UTC)
thread_title:  My ha'penny worth 

message: 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)
thread_title:  Carathéodory statement 

message: 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)
replies: text: 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)

text: "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)
thread_title:  Lead really needs to be simplified