Talk:Entropy/Archive 6

message: In Talk:Entropy of 23:26, 25 October, Bduke, a distinguished physical chemist and Wikipedia contributor and editor, erred seriously in two points. Quoting him (with my insertions of numbers), “[1] Maybe Frank Lambert's approach will spread, [2] but have a look at  Atkins, "Physical Chemistry", 8th edition, where it has spread somewhat but the terms disorder and, I think chaos, are still used.”
  
:In early October Bduke was not active in Talk:Entropy and thus undoubtedly was unaware of http://en.wikipedia.org/wiki/Talk:Entropy#Non-notable.3F of 9 October. Therein, his point  [1], a questioning of the spread of an approach to entropy as the measure of the dispersal of energy/T in a process, is conclusively countered.  That the majority of new editions of established US chemistry textbooks have adopted it within just three years of the publication of his principal articles is nothing less than astonishing support for the approach. Sales figures are guarded by publishers, but it is more probable than not that the majority of chemistry students in the US since Fall 2005 have been taught this approach. 
:Thus, the approach has already spread remarkably widely.  It is not an individual’s POV. (Of course it may take a generation to reach all scientists and science texts. That is the common history of new concepts, is it not?  But this approach already has been proved to have legs!)
 
Bduke’s second point [2] is a grave error perhaps because he just received his copy of Atkins’ “Physical Chemistry”, 8th edition and has had time only to scan it rapidly.  My gift copy came in March and I know its comments re entropy well, especially in comparison to previous editions. The change is not “somewhat” but profound and thorough.
:In prior editions (with his italics in the following quotes) , Atkins defined spontaneous changes as “accompanied by a dispersal of energy into a more disordered form.”  The direction of change, he wrote, is one “that leads to the greater chaotic dispersal of the total energy…”  “The spreading of the object’s energy into the surroundings as thermal motion is a natural consequence of chaos.”  “[The thermodynamic definition of entropy] is motivated by the idea that a change in the extent to which energy is dispersed chaotically can be derived by noting the quantity of energy that is transferred as heat…” [sic].  “The definition of a spontaneous change and its interpretation [is] in terms of the tendency of an isolated system to achieve greater disorder.”  There are some 27 uses of the words ‘order’ and ‘disorder’ in discussing particular applications of entropy change.
:The foregoing is certainly an emphasis on disorder and chaos in interpreting entropy, even when the dispersal of energy is associated with entropy change.  Contrast this to the 8th edition with its numerous clear statements about entropy, entropy change, and the dispersal of energy, never using ‘disorder’ in connection with a definition of entropy.  (The word ‘chaos’ does not appear in the Second Law chapter.  I visually checked and computer word-searched. The words ‘order’ or ‘disorderly’ appear a total of 4 times.)
::p. 77: “Can it be…that the direction of change is related to the distribution of energy?...this idea is the key…spontaneous changes are always accompanied by a dispersal of energy.” “…the signpost of spontaneous change: we look for the direction of change that leads to dispersal of the total energy of the isolated system.”  p. 78: “…in due course, we shall see that dispersal of energy and matter accounts for change…” “We shall see that the entropy…is a measure of the energy dispersed in a process…”The thermodynamic definition of entropy …is motivated by the idea that a change in the extent to which energy is dispersed depends on how much energy is transferred as heat.” 
::p. 81 “The concept of the number of microstates makes quantitative the ill-defined qualitative concepts of ‘disorder’ and ‘dispersal of matter and energy’ that are used widely to introduce the concept of entropy” Note: This quote appears to put ‘disorder’ on an equal footing with the qualitative ‘dispersal of matter and energy’.  However, Atkins consistently uses ‘dispersal of energy’ or of ‘energy and matter’ in his qualitative definitions of entropy change whereas he has discarded that use of ‘disorder’ in defining entropy here in this edition.  p. 88: “[re phase change] This decrease in entropy is consistent with localization of matter and energy that accompanies the formation of a solid from a liquid  or a liquid from a gas….If the transition is endothermic [as in melting, vaporization] the entropy change is positive, which is consistent with dispersal of energy and matter in the system.”  p. 89:  “…Trouton’s rule …strong molecular interaction…As a result there is a greater dispersal of energy and matter when the liquid turns into a vapour than would occur for a liquid in which molecular motion is less restricted.”
For over twenty years Atkins has used the phrase “energy dispersal” in connection with entropy change and entropy increase but always in previous books and text editions, it has involved “to disorder” or “to chaos”. Only in this new 8th edition has he deleted the connection of energy dispersal to ‘disorder”, consistently repeated that entropy change is related to energy dispersal, and associated energy dispersal with a greater number of microstates. This has been my emphasis since my original publications in 2002.  However, I have also emphasized giving the beginning student (who may not be able to handle abstract concepts such as  microstates) a thorough qualitative interpretation of all kinds of entropy change in terms of energy dispersal: http://en.wikipedia.org/wiki/Talk:Entropy/Archive4#Spontaneous_entropy_increase_always_involves_the_dispersal_of_energy and
http://en.wikipedia.org/wiki/Talk:Entropy#The_.E2.80.9CEntropy_of_Mixing_.E2.80.9C   FrankLambert 05:52, 27 October 2006 (UTC)
thread_title: Correction of error 

message: As to the following paragraph:
:Although Clausius did not specify why he choose the symbol "S" to represent entropy, it is arguable that Clausius choose "S" in honor of S. Carnot, i.e. Sadi Carnot, to whose 1824 article Clausius devoted over 15 years worth of work and research on.  From the first page of his original 1850 article "On the Motive Power of Heat, and on the Laws which can be Deduced from it for the Theory of Heat", Clausius calls "S. Carnot" the most important of the researchers in the theory of heat.
I brought this to discuss the fact tag.  It may be in 400+ pages of works and or notes of Clausius somewhere, but I have only limited access to these.  This seems to be an etymological issue, similar to the origin of the word "chemistry", e.g. see: Talk:Chemistry#Core etymology to intro.  I think finding the actual mental note by Clausius on his assignment of "S" will be difficult.  Yet it can be easily argued that, just as G = Gibbs, J = Joule, K = Kelvin, etc., that Clausius choose S = Sadi (first name by default since C = heat capacity had already been in use since the late 18th century by those as Joseph Black).  Does any have a problem with me removing the  tag and replacing it with an argument footnote # at the bottom of the page?  Then later, when someone finds a better explanation or an exact source, we can amend this. --Sadi Carnot 17:18, 29 October 2006 (UTC)
replies: text: I will amend this as there seem to be no objections; when someone finds a better source we can amend this further. --Sadi Carnot 10:53, 31 October 2006 (UTC)
thread_title: Regarding S = Sadi symbol assignment (speculation)

message: Moved to Talk:Entropy and life
:Why?  If it effects what's in this particular article it should not be moved.
:In any case, this sentence needs work, "Over the last century, as stemming from Clausius' 1863 memoir "On the Concentration of Rays of Heat and Light, and on the Limits of its Action", much writing and research has been devoted to the relationship between thermodynamic entropy and the evolution of life." •Jim62sch• 21:48, 8 November 2006 (UTC)
replies: text: I edited it based on the examples at the other talk page. •Jim62sch• 21:51, 8 November 2006 (UTC)
replies: text: Jim62, good changes; I agree with you on the move, but for the sake organization I moved it.  Having simultaneous talks going on two separate pages on the same topic is messy, e.g. I just replied to a comment by Pjacobi on the same issue, related to the changes you just made, on the other talk page.  P.S. I'll be cuting back on my edit time over the next two months. Later: --Sadi Carnot 06:28, 9 November 2006 (UTC)
thread_title: [[Entropy and life]]

message: I'm unhappy with the teaser picture. Both ice melting and water freezing can occur spontanously and with increasing entropy. It all depends on the mixture and temperature of the ingredients. --Pjacobi 19:37, 8 November 2006 (UTC)
replies: text: Maybe change the caption to "Ice melting in a warm room"? PAR 19:55, 8 November 2006 (UTC)
replies: text: Ice melting, or solid/liquid/gas phase and structure change for water, is the most common entropy change example of all time.  Ice melting and entropy change is in nearly every chemistry textbook as an example. Didn't you see the disgregation article I wrote just to accompany that picture?  If, however, you know of more entropy change picture examples, feel free to add them to the article.  P.S. it’s worded to match the exact wording that Clausius originally used.  Later: --Sadi Carnot 06:36, 9 November 2006 (UTC)
replies: text: I thought that Pjacobi was making the point that if you have a glass of ice and water and the ice is very cold, it could freeze the water, and still entropy would increase. Correct me if I am wrong, but I thought his problem could be solved by re-doing the caption, not the picture. PAR 20:14, 10 November 2006 (UTC)
replies: text: That's what I meant. But only re-doing the capture wouldn't do anything against the preconception, that only melting, not freezing, can increase entropy. --Pjacobi 20:25, 10 November 2006 (UTC)
replies: text: May I humbly suggest "In the system of ice and water, energy disperses from the water to the ice, reducing the temperature differential and increasing entropy." If you wanted to include the melting/freezing aspect this could be covered by "If the resulting equilibrium is above 273 K (0 C) the ice will have melted, if below that temperature the water will have frozen." Just an idea....dave souza, talk 09:08, 12 November 2006 (UTC)
replies: text: That, or something similar, sounds fine to me. PAR 10:31, 12 November 2006 (UTC)

text: I think that scenario is being considered only as a possibility, but if it is always considered to be true, the caption on the picture should make that point. Either way, you make a good point - To be correct the first sentence above should read - "In the system of ice and water, energy disperses from the water to the ice, with a subsequent increase in entropy"  (dropping the "temperature differential" part). The point that Pjacobi was making was to consider the possibility that the ice was colder than the water, in order to avoid the prejudice that ice melting in an ice/water system was always an increase in entropy. To point out that water freezing in the ice/water system could be an entropy increase as well. PAR 16:15, 12 November 2006 (UTC)
replies: text: A fair point which I was leaving to the more detailed paragraph below, and of course the temperatures in the "ice+water" system will depend on timing: a warmer drink will have sub-zero ice from the freezer added, then will tend towards zero. PAR's suggestion of removing the "temperature differential" point would avoid the problem, and  we could always add something like "At the same time the water temperature will usually be affected by the surroundings – see explanation below."  .... dave souza, talk 16:26, 12 November 2006 (UTC)
replies: text: Please, folks, let's stick to the main-stream types of presentations on the main page.  The phrase: "energy disperses (spreads out) from the water to the ice", for example, is completely non-standard, it has been a huge point of controversy on the talk page, it was recently at articles for deletion, where the majority of people had never heard of this term, and it is one of the lowest-ranked keywords according to Google search results.  The correct and classical phrasing is: "heat flows from the hot body to the cold body and entropy increases."  Remember, the concept of heat flow between bodies goes back to the 5th century B.C. days of Heraclites and is the core principle of thermodynamics.  Let's try to write an article that we can be proud of. --Sadi Carnot 06:28, 13 November 2006 (UTC)
replies: text: Sadi - I'm not going to get bent out of shape for a case where there actually is "energy dispersal" or "heat flow". I DO oppose the idea that ALL entropy change is "energy dispersal" or "heat flow". I'm not well versed on the conditions under which the standard ice/water/room example occurs, but we should state them explicitly in the caption, and hopefully avoid any misconceptions such as the idea that ice melting in water is always an entropy increase. What are the conditions for the ice/water/room example? Ice and water at 0 C and room at room temperature? Ok, fine the ice melts, the ice/water system stays at 0 C and the room - what? PAR 16:59, 13 November 2006 (UTC)
thread_title:  Ice melting 

message: See Quantum Mechanics: the molecules are never all in one place.  Oh yes, they could be at 0K, but as we know the uncertainty principle rules out 0K being an achievable temperature.  So, is this a direct quote from a source, or a synthesis? I'm guessing the latter as the ref deals with applied mathematics. •Jim62sch• 21:01, 12 November 2006 (UTC)
replies: text: Yes, this is a direct quote from a source (that's why there is a footnote next to the sentence). --Sadi Carnot 05:54, 13 November 2006 (UTC)
thread_title: "when all the molecules are in one place"