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Q:
What fluoresence have to do with glow in the dark stars?
- Anonymous
A:
'Fluorescence' is another word for a special type of glowing. When
light gets absorbed by a material, it gives energy to the material. In
some special materials, that energy is stored in special ways that let
it come out later as light, again. So the material glows for a while.
Glow-in-the-dark
stars use fluorescent chemicals. The ones I've seen will glow nicely
just after you turn out the lights, but if you wake up in the middle of
the night they don't glow much anymore because the energy has leaked
out.
Most fluorescence only lasts a tiny fraction of a
second
after the material absorbs the light. Some special materials are
'phosphorescent', which means their fluorescence can last for a long
time. Obviously glow-in-the dark stars are phosphorescent.
-Tamara and Mike
(published on 10/22/2007)
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