Bob Sciamanda said, "I think the argument is from thermodynamic
principles and asserts that the energy spectrum of a black body in
equilibrium with a definite temperature environment should be
independent of the details of its structure. Thus in calculating the
universal BB spectrum function dE(lamda) one is free to choose any valid
BB construction for the calculational model."
Okay, that agrees with my thinking. The problem is that the textbooks
have just finished following the Rayliegh derivation (standing waves) in
order to show it leads to the "ultraviolet catastrophe." Then when they
switch to the Planck derivation, they continue to use the "cavity with
standing waves model." I think this model is not necessary, but
students get confused and think that standing waves are a necessary
component of the quantum explanation of BBR. That, in fact, was how my
son posed the question to me. He said, "I don't see what standing waves
have to do with it. Can you explain that to me?" And I couldn't.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu