Question: What are phosphors?
Answer:
A phosphor is a chemical substance that gives off (radiates) visible light after it has been energized. NOTE: Phosphors may or may not contain the phosphorus element.
Scientists have created thousands of different kinds of phosphors. Phosphors differ in:
1. The type of energy they require to be energized
2. The color of the visible light that they give off.
3. The length of time that they glow after being energized, which is known as the persistence time.
If the phosphor continues to emit light after the source light is removed, the phosphor is referred to as being phosphorescent.
Glow-in-the-dark toys contain phosphors that are phosphorescent. These phosphors can be energized with visible light, such as from sunlight or a lamp.
The common phosphors used for glow-in-the-dark toys are Zinc Sulfide and Strontium Aluminate. Of these two phosphors, strontium aluminate has the longer persistence time.
Some phosphors must be energized by ultraviolet light, and some of the phosphors are phosphorescent. A source of UV is sunlight and a black light.
There are natural phosphors, such as in the phosphors in the exoskeleton of scorpions. These are excited by ultraviolet light from a black light, and are not phosphorescent. This means they glow only while receiving UV light.
Vaseline (petroleum jelly) contains chemicals that exhibit phosphorescence when excited with black light.
Discover for Yourself
Put a thick layer of Vaseline on your lips, and then in a darkened room, look in a mirror as you shine a black light on your lips.
CAUTION: DO NOT SHINE BLACK LIGHT INTO YOUR EYES. IT COULD PERMANENTLY DAMAGE YOUR EYES.
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