The Conceptual Meaning of Thermodynamic Entropy in the 21st Century -ADDENDUM

Some blog followers might be interested in the following ADDENDUM [Hake (2011b)] to my post “The Conceptual Meaning of Thermodynamic Entropy in the 21st Century” [Hake (2011a)]:

PhysLrnR’s Paul Camp (2011a) wrote:

“Having taught thermal physics this semester, I'll testify that, at least for my 5 beginners, the point where phase space appeared totally baffled them. I brought it up only as part of a historical note about the arguments between Planck and Boltzmann so I didn't dwell on it, but phase space is perhaps a great deal less transparent to beginners than Lambert appears to believe. What actually spoke to them pretty powerfully (because it was embedded in a dice game activity) was Shannon entropy.”

To which Frank Lambert (2011b) replied [bracketed by lines “LLLLL. . . . “; my insert at “. . . . .[[insert]]. . . .”; my CAPS]:

LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL
MY APOLOGIES TO PROF. CAMP AND ALL PHYSICISTS!!

That brief piece . . . .[[“The Conceptual Meaning of Thermodynamic Entropy in the 21st Century” (Lambert, 2011a)]]. . . . . was designed primarily for chemists teaching beginners. But, foolishly, I changed my standard opening description of “entropy is fundamentally an evaluation of how spread out/dispersed in SPACE [or in a substance] is....” and included “phase space” rather than emphasizing simple “space”.

(The first example in most first-year chemistry texts is the isothermal expansion of a gas in a chamber when a valve to an adjoined evacuated chamber is opened: the kinetic and potential energy of the gas is unchanged, but it is spread to the larger final accessible space.)

I, agreeing with Professor Camp, disagree with some chemistry texts that then try to introduce microstates, baby phys chem, and inklings of phase space to naive frosh. The best chemistry texts - in my opinion (of the 22 first-year texts that have adopted my approach) -- are by Burdge (2011) or by Burdge and Overby (2012). They superbly present the entropy increase of a chem process in changes of volume, temperature, molecular complexity, molar mass, phase change and chemical reaction -- with diagrams of differences in energy levels/occupancy of energy levels, but not a word about microstates or Boltzmann stat mech or phase space. I think that those next steps in sophistication should all be left for physical chemistry, the usual third-year course in chemistry.

ALL references to Wikipedia “Entropy”. . . . .[[ http://en.wikipedia.org/wiki/Entropy]]. . . . . and “Entropy (energy dispersal)”. . . . .[[ http://en.wikipedia.org/wiki/Entropy_(energy_dispersal)]]. . . . SHOULD BE IGNORED! The former is a hopeless morass with Shannon enfolding Clausius, Maxwell, Boltzmann and Gibbs, while the latter was rewritten by a professor in economics -- from a spin-off by a non-academic person who attempted to have "energy dispersal" deleted from Wikipedia and was subsequently barred from contributing!
LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL

See, also the cogent response to the above by Paul Camp (2011b) who wrote (in part):

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
One of the reasons I taught Thermal Physics this semester was because I always hated it and that was because some of the fundamental concepts (notably entropy) never made any sense to me.

It took me some years, as a student, to understand what entropy is and the epiphany came when I tried to figure out what units it is measured in (oddly, none of the textbooks I used paid attention to this). When I realized it was basically an energy, then the first law made complete sense to me -- it is that portion of the energy of a system that is not available for doing work. All that crapola about disorder and everything was getting in the way of understanding.

Afterwards, the link with disorder made some sense. If all the particles in a gas are moving in the same direction (low disorder) they can do a lot of work, but if they are banging around at random, not so much.
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

BTW - To education aficionados Frank Lambert is less well known for his “Conceptual Meaning of Thermodynamic Entropy” than his “Post Gutenberg University Breakthrough” - see e.g.: “Editorially Speaking: Effective Teaching of Organic Chemistry” [Lambert (1963)] and the all-time classic must read: “The Lecture System in Teaching Science” [Morrison (1986)].


Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References
which Recognize the Invention of the Internet (PEDARRII)

rrhake@earthlink.net>
Links to Articles: http://bit.ly/a6M5y0
Links to SDI Labs: http://bit.ly/9nGd3M
Blog: http://bit.ly/9yGsXh
Academia: http://iub.academia.edu/RichardHake


REFERENCES [All URL’s accessed on 18 Dec 2011; most shortened by http://bit.ly/.]
Camp, P. 2011a. “Re: The Conceptual Meaning of Thermodynamic Entropy in the 21st Century,” online on the CLOSED! :-( PhysLrnR archives at http://bit.ly/rViO7S. Post of 27 Dec 2011 23:13:05-0500 to PhysLrnR. To access the archives of PhysLnR one needs to subscribe, but that takes only a few minutes by clicking on http://bit.ly/nG318r and then clicking on “Join or Leave PHYSLRNR-LIST.” If you're busy, then subscribe using the “NOMAIL” option under “Miscellaneous.” Then, as a subscriber, you may access the archives and/or post messages at any time, while receiving NO MAIL from the list!

Camp, P. 2011b. “Re: The Conceptual Meaning of Thermodynamic Entropy in the 21st Century,” online on the CLOSED! :-( PhysLrnR archives at http://bit.ly/vUdYbL. To access the archives of PhysLnR see the information above in Camp (2011a).

Hake, R.R. 2009. “In Defense of Wikipedia” online on the OPEN ! AERA-L archives at http://bit.ly/fb4bJx. Post of 31 Aug 2009 16:41:53-0700 to AERA-L, Net-Gold, and Math-Teach. The abstract and link to the complete post were distributed to various discussion lists and are also on my blog “Hake'sEdStuff” at http://bit.ly/tTjuo1.

Hake, R.R. 2011a. “The Conceptual Meaning of Thermodynamic Entropy in the 21st Century,” online on the OPEN! AERA-L archives at http://bit.ly/s7heFg, post of 17 Dec 2011 21:35:08-0800, transmitted to AERA-L, Net-Gold, and various other discussion lists.

Hake, R.R. 2011b. "The Conceptual Meaning of Thermodynamic Entropy - ADDENDUM," online on the OPEN! AERA-L archives at http://bit.ly/vADrgv. Post of 18 Dec 2011 13:20:41-0800 to AERA-L, Net-Gold, and various other discussion lists.

Lambert, F.L. 1963. “Editorially Speaking: Effective Teaching of Organic Chemistry,” J. Chem. Ed. 40: 173-174; online at http://bit.ly/sZnEbI.

Lambert, F.L. 2011a. “The Conceptual Meaning of Thermodynamic Entropy in the 21st Century,” International Journal of Pure and Applied Chemistry 1(3), online at http://bit.ly/upGF5C, click “Full Article PDF” after accessing the URL. At http://entropysite.oxy.edu/, Lambert wrote “[This article's] major goal is to explain why brilliant physicists and chemists of the past century failed to explain entropy clearly - i.e., to develop an adequate conceptual explanation for the success of dS = dq/T. Certainly, the 'driving force' in this relationship is simple: the nature of q, energy, is to spread out, disperse in space/ in phase space if its constraints are lessened or removed.”

Lambert, F.L. 2011b. “Re: The Conceptual Meaning of Thermodynamic Entropy in the 21st Century,” online on the CLOSED! :-( PhysLrnR archives at http://bit.ly/tl0unt. Post of 17 Dec 2011 22:15:12-0800 to PhysLrnR. To access the archives of PhysLnR see the information above in Camp (2011a).

Morrison, R.T. 1986. “The Lecture System in Teaching Science,” in Proceedings of the Chicago Conferences on Liberal Education, Number 1, Undergraduate Education in Chemistry and Physics (edited by Marian R. Rice). The College Center for Curricular Thought: The University of Chicago, October 18-19, 1989; online at http://entropysite.oxy.edu/morrison.html thanks to Frank Lambert.