When you think of fluorescence you think of terrible, garish
paper or clothing. But plenty of fluorescence can be found in
nature, and sometimes it can be used to check what's purely
natural. You can start in your very own kitchen, with olive oil
- make it glow like it's radioactive with this easy experiment.
Fluorescence is a slight quirk on how light generally works.
Most often a photon is absorbed by an atom and emitted again at
the same energy level as before. A fluorescent object will take
in light at one energy level, and spit it out at a slightly
lower level. Often the fluorescent objects that we're sold will
absorb ultraviolet light, which we can't see, and then re-emit
it as visible light, seeming to glow on their own. Ultraviolet
light isn't needed to make things fluoresce. Olive oil, though
it's dull under regular light, is a fluorescent substance. Hit a
clear glass of olive oil with a green or blue-violet laser. If
you choose a laser with a wavelength of 405 nanometers, the oil
should glow red. A