# Talk:Second law of thermodynamics

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The text states, "The is regarded as the only true isolated system, the Earth can be viewed as a closed system, although this is not entirely accurate, it is a fairly good approximation." I think something vital is missing after the first "is" - but what? The universe? I'm not sure.--Bob_M (talk) 04:32, 23 May 2007 (CDT)

My guess is, it was supposed to be "This is" (meaning the universe), not "The is". I've reworded it slightly, working under that assumption. If I'm wrong, hopefully someone will fix it. --jtltalk 04:41, 23 May 2007 (CDT)

Good article. I think even I understand what this is about now. High school never managed to do that. :D --AKjeldsen 08:57, 23 May 2007 (CDT)

## Possible error in second law of thermodynamics entry

I don't agree with the following quote:

A germinating seed or an embryo developing in a fertilized chicken egg are often naively cited as examples of isolated systems in which an increase in order, or decrease in entropy occurs spontaneously. It is evident, however, that respiration, assuming O2 is present, produces an increase in entropy in the form of heat, which more than compensates for the decrease in entropy that arises when the elements present in the seed or in the yolk of the egg are organized into tissues of the plant or animal. (Klein, J. J. “An Apparent Violation of Second Law of Thermodynamics in Biological Systems.” J. Chem. Educ. 1979, 56(5), 314.)

To me this is like giving the wrong answer to the following question:

Suppose a gas in a cylinder with a piston is under pressure. The latch on the piston is released and the gas expands. This is consistent with the second law because the gas is going from more order to less order, less entropy to more entropy. When the gas is compressed, the gas goes from less order to more order. Why is this not a violation of the second law?

Correct answer: In the expansion, the gas is an isolated system. In the compression, the gas is not an isolated system. The second law only applies to isolated systems.

Wrong answer: In the expansion, entropy increases. In the compression, the entropy of the system decreases, but the entropy of whatever is pushing the piston increases. Davidmihjn (talk) 05:31, 2 March 2012 (UTC)

If this is a quibble about not explicitly stating something is an isolated system, then you bore me. steriletalk 05:42, 2 March 2012 (UTC)
It might be worth mentioning that there really isn't such thing as a "true" isolated system. The only isolated system that is isolated fully and permanently is the universe itself. gnostic 14:34, 2 March 2012 (UTC)

## Possible ideas for additions to the page

I was just wondering if it would be useful to bring up the statistical nature of entropy, or the work to develop a nonequilibrium thermodynamics by Prigogine and others.Drakvl (talk) 18:43, 21 September 2012 (UTC)

## from page

Supposedly rational scientists can be as irrational as creationists about the connection between evolution and thermodynamics. In "Entropy and evolution" (Am. J. Phys., Vol. 76, No. 11, November 2008) the author calculates the change in entropy during evolution in joules/degree using the Boltzmann constant. The truth is that the second law of thermodynamics does not apply to the evolution of stars or biological evolution. The following links explain why this American Journal of Physics article should be retracted: http://creationwiki.org/Pseudoscience_in_the_American_Journal_of_Physics

Davidmihjn (talk) 00:46, 3 January 2013 (UTC)

Bajezus Mr. Roemer, your criticsms (which you are barely expressing) are getting more and more bizarre.
• It is most certainly the case that the second law applies to stellar evolution and to evolution. Both involved individual nuclear and chemical reactions for which the next effect is to dissapate heat. Further, entropy is a state function. You can determine an entropy difference of the entired system (which may be a LARGE system) and the entropy must have increased during the process. By your "logic", a ball wouldn't give off heat as it loses its energy as it comes to rest after bouncing.
• I do tend to agree that saying an organism is 1000 more or less likely is unproductive, and that the calculation should be expressed in terms of energy. It should be readily apparent, however, that 420 x 1020 J/(s*K) is quite sufficent for evolution to occur. Put another way, if it is sufficient to sustain life an the regulat genetic processes that support it, then it is sufficent to support evolution.