[Fis] "Distribution of Energy is (not) the same as "disorder"?

Dear Colleagues:

I would like to open an academic aspect of the entropy issues.

I recently rec'd the email copied below. It is being circulated among leaders of the chemical community.

The objective of the dialogue is to substitute the words "distribution of energy" in the place of "disorder" in developing a semantic terminology for entropy. The arguments for this substitution are given in publications that are referenced. Many of these are available on line.

I ask the following questions:

What are the views of experts on entropy on this semantic substitution?

(No syntactical change is proposed. The general problem of relating syntax to semantics extends across the sciences and includes mathematics and models.)

 How would this change of semantics influence the philosophy of science associated with the concept of entropy?

Cheers

Jerry LR Chandler

-----Original Message-----
From: CHEMICAL INFORMATION SOURCES DISCUSSION LIST
[mailto:CHMINF-L@LISTSERV.INDIANA.EDU]On Behalf Of
dzrlib@LIBRARY.CALTECH.EDU
Sent: Tuesday, August 17, 2004 1:10 PM
To: CHMINF-L@LISTSERV.INDIANA.EDU
Subject: Entropy is NOT disorder ...

I would like to recognize an exciting example of what one dedicated individual can accomplish. �Frank L. Lambert, Professor Emeritus, Occidental College has, in the past six years of his retirement, worked unceasingly on effecting a fundamental change in the description of thermodynamic entropy in first-year college textbooks.

Frank's article "Disorder - A cracked crutch for supporting entropy discussions" in the Journal of Chemical Education, 2002, 79(2), 187-192, showed that treating entropy change as involving "disorder" was not based on modern science and is potentially misleading to students.

Since textbooks do not readily alter their presentation of basic concepts, it is nothing short of amazing that seven of the following ten texts have deleted any mention of "disorder" (and the other three, use it sparingly or strongly advise against its use). �

For them all now to describe entropy change in terms of "the spreading or dispersing of energy (as a function of temperature)" signifies the utility of this concept in good teaching.

Testbooks for Science Majors ...

1. "Chemistry: The Molecular Science", 2nd. ed., 2004. �Moore, Stanitski, and Jurs state that [it] is improved because ... the "...treatment of entropy in Chapters 14 and 18 has been rewritten to make it clear that entropy measures dispersal of energy" rather than "disorder". �

2. "Chemistry", 4th edition, 2005. Brady & Senese state "We have changed our approach to presenting Thermodynamics... [by explaining] entropy as a measure of the number of equivalent ways to spread energy through a system." ��

3. "Chemistry", 8th ed., 2005. �Chang mentions "disorder" in connection with entropy but specifically points out the inadvisability of using "disorder" as a basis for understanding entropy. Further, he has an excellent explanation of the importance of microstates in evaluating entropy change. �Chang's "Physical Chemistry for the Chemical and Biological Sciences" (University Sciences, 2000), has no mention of "entropy as disorder").

 4. "Thermodynamics", 2004. �Spencer, Moog, and Farrell completely omit references to "disorder" of "messy desks" which appeared in a previous trial edition and replaces them with viewing entropy as related to "how energy can be spread out in a system".

5. "Principles of Modern Chemistry", 5th ed., 2005. �Oxtoby, Gillis and Nachtrieb have removed any references to entropy as a measure of "disorder". �This text's relating of entropy increase to greater numbers of microstates, as shown by the Boltzmann entropy equation, is perhaps the most thorough in any general chemistry text.

6. "General Chemistry: Principles and Modern Applications", 8th ed., 2005. �Petrucci, Harwood and Herring present an unusually readable development of entropy as increasing when there are more microstates among which the energy of a system can be distributed. �This is accompanied by a simple introduction to increased density of energy levels (and therefrom, more microstates) when the volume of a gas spontaneously increases. �

7. "General Chemistry", 4th ed., 2005. �Hill, Petrucci, McCreary and Perry still employ the word "disorder" in referring to entropy change in several places, but it is primarily as a bridge for those students who have heard the expression. �Overall, the authors use "entropy change as a dispersal of energy". ��

8. "General Chemistry", 8th ed., 2005. �Ebbing and Gammon mention "molecular disorder"...in the sense that the energy is distributed over many energy states, rather than concentrated...". �The authors further describe as "unfortunate" the picture of entropy as a measure of the disorder of books on desks that have been made messy by a person moving objects. �The text emphasizes that, fundamentally and scientifically, entropy involves both energy dispersal and is a function of temperature.

Textbooks for non-science majors ...

 9. "Chemistry for Changing Times", 10th ed., 2003. �Hill and Kolb define entropy not as being "disorder" but as "measur[ing] energy spreading out, not things." �

10. "Conceptual Chemistry", 2nd ed., 2nd printing, 2003. �Suchocki replaced the section heading that described the second law as "Order Tends to Disorder" to "Entropy Is a Measure of Dispersed Energy"..."This fits with our everyday experience...." �and helps students understand and easily calculate the direction of chemical reactions. �

Additional information is available at [www.entropysite.com] and Frank can be contacted at: flambert@att.net

Dana L. Roth
Millikan Library / Caltech 1-32
1200 E. California Blvd. Pasadena, CA 91125
626-395-6423 �fax 626-792-7540
dzrlib@library.caltech.edu
http://library.caltech.edu/collections/chemistry.htm

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Received on Thu Sep 9 20:36:44 2004