In the following experiment, there is a device below the Bohr model that works like a
prism or a diffraction grating. It shows the atomic spectrum for a hydrogen atom.
Whenever a photon is emitted, it shows up on the spectrum according to its wavelength.
Huh. Each time the electron jumps down a level it produces a photon, and the
same jumps produce the same colors.
When you have a whole lot of atoms, I'll bet you get all these different lines
appearing at once.
Exactly, and that's what scientists mean by the atomic spectrum. By the way, the
converse is true, too. Those same color photons are the only ones that will bump the
electron up to higher levels. Photons of other frequency will pass right through the
That would mean atoms are kind of "transparent" to all light except their own "team colors."
We keep talking about the "color" of these photons. Does that mean that atoms only
interact with visible light? What about other kinds of electromagnetic radiation?
We've been talking about visible light because it's the easiest to experiment with. But
you're right, we should talk about the "frequency" or "wavelength" of the photons, not
their color. In fact, we're now going to talk about how heavier atoms, which have
lots of electrons, tend to interact with higher energy waves, like x-rays. We
can go ahead and talk about these heavier atoms, or look at some specific examples,
such as how hospital x-ray machines create the x-rays, or how they absorb them to make