That would mean that the atoms were only emitting waves of certain frequencies. Do all atoms
create the same colors?
Kind of like wearing your team colors.
Exactly. If you put light from a common streetlamp through a prism, or look at the
light through a diffraction grating, you will see distinct lines. Two common kinds of
street lights use sodium vapor and mercury vapor bulbs. Each of these lights has a
different spectral "signature", and you can tell what kind of lamp it is by its
Is that why different street lights seem to be different colors?
You got it. This technique is so reliable that scientists can tell what elements they
are looking at just by reading the lines. Spectroscopy
(this page is currently under construction) is the science of using spectral lines
to figure out what something is made of. That's how we know the composition of distant
stars, for instance.
Wait a second. We learned earlier that
radiation is caused by wiggling charges, and the rate of the wiggling determines the
wavelength. If only some wavelengths are coming out of the atom, that would mean that
the electrons are wiggling at only some frequencies. How does that happen?
That was the big puzzle. Fortunately, a Danish physicist named Niels Bohr came up with