While entropy is often described as “disorder,” it is better thought of as a measure of how spread out energy is within a system. To illustrate this interpretation of entropy to introductory college or high school students, several activities have been created. Students first study the relationship between microstates and macrostates to better understand the probabilities involved. Then, each student observes how a system evolves as energy is allowed to move within it. By studying how the class’s ensemble of systems evolves, the tendency of energy to spread, rather than concentrate, can be observed. All activities require minimal equipment and provide students with a tactile and visual experience with entropy.
References
1.
MCAT lists thermodynamics and entropy among the possible topics, although it defines entropy as “disorder”; https://www.aamc.org/students/applying/mcat/about/.
2.
R.
Baierlein
, “Entropy and the second law: A pedagogical alternative
,” Am. J. Phys.
62
, 15
–26
(Jan.
1994
).3.
T. A.
Moore
, and D. V.
Schroeder
, “A different approach to introducing statistical mechanics
,” Am. J. Phys.
65
, 26
–36
(Jan.
1997
).4.
D. F.
Styer
, “Insight into entropy
,” Am. J. Phys.
68
, 1090
–1096
(Dec.
2000
).5.
H. S.
Leff
, “Removing the mystery of entropy and thermodynamics — Part I
,” Phys. Teach.
50
, 28
–31
(Jan.
2012
).6.
F. L.
Lambert
, “The conceptual meaning of thermodynamic entropy in the 21st century
,” Int. Res. J. Pure Appl. Chem.
1
, 65
–68
(2011
).7.
H. S.
Leff
, “Removing the mystery of entropy and thermodynamics — Part V
,” Phys. Teach.
50
, 274
–276
(April
2012
).8.
F.
Jeppsson
, J.
Haglund
, and H.
Strömdahl
, “Exploiting language in teaching of entropy
,” J. Balt. Sci. Educ.
10
, 27
–35
(2011
).9.
B. D.
Geller
et al., “Entropy and spontaneity in an introductory physics course for life science students
,” Am. J. Phys.
82
, 394
–402
(May
2014
).10.
National Experiment in Undergraduate Science Education (Project NEXUS), http://nexusphysics.umd.edu.
11.
M. C.
LoPresto
, “A simple statistical thermodynamics experiment
,” Phys. Teach.
48
, 183
–185
(March
2010
).12.
T.
Timberlake
, “The statistical interpretation of entropy: An activity
,” Phys. Teach.
48
, 516
–519
(Nov.
2010
).13.
The zero-point energy does not change; therefore, it does not play a role in the thermodynamics of the system and can be ignored for these activities.
14.
See supplemental material at TPT Online under the References tab at http://dx.doi.org/10.1119/1.4961175 for a derivation of an Einstein solid’s multiplicity.
15.
A. R.
Daane
, L.
Wells
, and R. E.
Scherr
, “Energy theater
,” Phys. Teach.
52
, 196
–199
(May
2014
).16.
17.
S.
Wheaton
, Interacting Einstein Solids And Entropy Worksheet and Model
, http://www.compadre.org/Repository/document/ServeFile.cfm?ID=12959&DocID=3538 (2013
).18.
19.
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