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In response to my post "The Conceptual Meaning of Thermodynamic
Entropy in the 21st Century" [Hake (2011)]
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-yeartexts 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 an 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! . . . .
[[But see "In Defense of Wikipedia" [Hake (2009)]]. . . . . .
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
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. 2011. "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.
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.