Glowing When the Lights Are Off
Some materials glow after all the lights are turned off. This type of glow is called phosphorescence. A phosphorescent material absorbs and slowly re-emits energy in the form of light. Remember those little stars you stuck to your roof as a kid? Those stars used a phosphorescent material to glow after you turned out the lights.

Ultraviolet (Black Light) Glowing
Some glowing materials will only work in the presence of ultraviolet light. These materials have a chemical property called fluorescence. Fluorescent materials absorb energy just like phosphorescent materials, but fluorescent materials re-emit their energy as light much quicker. That means the best way to see these materials in action is in a dark room with nothing but a black light.

Glow Sticks
Glow sticks are yet another way that materials can glow in the dark. Glow sticks create their glow through a chemical reaction between different chemicals. The light that this chemical reaction produces is called chemiluminescence. Just like the other two types of materials, you can see chemiluminescent materials the best in the dark.