A simple experiment for measuring the order of magnitude of the mean thermal velocity of the molecules in the vapor above a shallow dish of fluid is discussed.

1.
A. Friedrich, H. Langeheine, and H. Ulbricht, Experiments in Atomic Physics (Murray, London, 1966), pp. 47–48.
2.
Tamme, Math. Ph. Ch. in der Schule, 1952, p. 328.
3.
D. Halliday and R. Resnick, Physics (Wiley, New York, 1978), Chap. 9.
4.
The mass of the container is subtracted automatically.
5.
Reference 3, Chap. 24.
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