The television itself also displays some luminescence. In this short activity you can investigate the light emitting properties of the TV or computer.
The general definition of a phosphor is a solid material which when provided sufficient energy emits light due to luminescence. Phosphors can be found in phosphorescent materials as well as inside the glass tubes of fluorescent lamps. Phosphors made up of the same materials phosphorescent objects, like glow-in-the-dark toothbrushes, can also be found in electroluminescent materials. The green, faintly glowing night lights that can be plugged into the household electrical outlets and the Timex Indiglo watches utilize the process of electroluminescence to emit this characteristic light.
Before you turn off your computer monitor, make the room as dark as possible and then turn it off.