Hot Atoms

Narrator: ``Faraday has elucidated the nature of electrical phenomena, Maxwell has formulated the physical laws, and Joseph John Thomson has found the ELECTRON. It seems to be a fundamental particle, tied up in the atom. Electrons are discrete pointlike things with negative electric charge, and moving them around creates esoteric phenomena like magnetism, so the atoms that make up everyday stuff must look something like this (holds up a RAISIN BUN) with the mushy brown part embodying most of the mass and the positive charge required to make the overall atom electrically neutral. We just need to nail down the details of how jiggling raisin buns explain everything.''

Balmer and Rydberg [conducting experiments with a Bunsen burner and a nichrome wire]

Balmer scratches head, mumbles: ``This darn high school teaching is driving me crazy,'' and writes on board near H atom spectrum:

$$\lambda = { h m^2 \over m^2 - 4 } \quad \hbox{\rm for integer } m > 2.$$

Rydberg: ``Dr. Balmer, I decided to visit you in Basel because I am so very excited with your equation for the H atom lines. If I turn it upside down I can write it:

$${1 \over \lambda} = R_H \left( {1 \over m_2^2} - {1 \over m_1^2} \right) \quad \hbox{\rm with } m1 > m2 .$$

``It then fits additional hydrogen lines.'' [pointing to spectrum from sun] ``But more importantly, with a slight modification I can fit lines from other atoms as well. This seems to be a universal equation to fit all spectral lines. I cannot understand why they won't grant me tenure back in Lund. Just to get at them, I'm naming the new fundamental constant R_H the Rydberg constant - after me!''

Narrator: ``These empirical formulas are certainly useful. But what do they mean?''

Planck: Enters, takes chalk from Balmer's hand, walks to blackbody spectrum on next blackboard panel and fills in corrected theoretical spectrum.

``I was able to get rid of the so-called ultraviolet catastrophe and make the theoretical BLACKBODY SPECTRUM agree with the experimental data by assuming that the energy of electromagnetic waves was not a continuous property, but came quantized in fixed multiples of . . . '' [writes on board]

$$E = h \nu$$

`` . . . where $\nu$ is the frequency of the light. I have no idea what this means either, but it seems to work.''

[Leaves chalk under PHOTOELECTRIC EFFECT.]