Glow-in-the-dark Stars

Most recent answer: 10/22/2007

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)