Providing students of introductory thermal physics with a plot of the heat capacities of many low density gases as a function of temperature allows them to look for systematic trends. Specifically, large amounts of heat capacity data not only allow students to discover the equipartition theorem but also point to its limited applicability. Computer code to download and plot the temperature-dependent heat capacity data is provided.

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See supplementary material online for the computer code to reproduce Fig. 2.
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Reference 2 gives an early and significant role to the equipartition theorem compared to other textbooks at a similar level; for example, instead of giving the derivation of the formulae for adiabatic, quasistatic compression of an ideal gas in terms of γ : = C P / C V, Schroeder uses f, compared to the more conventional usage of γ; e.g.,
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I follow NIST's usage of the term “data”; the heat capacities and other tabulated quantities in Ref. 10 are based on mixtures of calculations and empirical data; i.e., some heat capacities are computed using spectroscopically determined energy levels.
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21.
When following Ref. 2 quite closely—giving prominence to Fig. 1—I would frequently observe the appearance of C V = f N k B / 2 as a general expression for heat capacity in students' work, including situations where the equipartition theorem was not applicable. This misuse was possibly due to the “theorem” terminology, suggesting a good opportunity to discuss the role of precise mathematical results in physics: their premises are often only approximately satisfied in the physical world.
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The mode frequencies are taken from the fundamental bands listed in Table 56 of Herzberg (Ref. 16) as he recommends on p. 504.
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“Hindered internal rotation” refers to the rotation of groups of atoms within a molecule (e.g., a methyl group), where the rotation encounters potential barriers. See, for example, Ref. 16.
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Supplementary Material

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