The Secret Behind "The Glow"
By Rou Pan
By Rou Pan
Have you ever been fascinated as a child by things that glowed in the dark? To appease your childhood curiosity, the secret behind their luminescence is phosphor!
Two of the most common phosphors found in glow-in-the-dark toys are zinc sulfide and strontium aluminate, which can be energized by normal light. They are mixed with plastic and molded into a desired shape. After being energized and placed in the dark, phosphors emit a glow, which is usually green, as they slowly release their stored energy. However, strontium aluminate is newer and has greater persistence, meaning it glows longer than zinc sulfide.
Other products that contain phosphors include TV screens, computer monitors, and fluorescent lights. Whereas the phosphors in TV screens and computer monitors are energized by an electron beam, the phosphors in fluorescent lights are energized by ultraviolet light.
Glow sticks also glow in the dark, but it is called chemiluminescence and are due to a chemical reaction rather than exposure to light.
Nature also exhibits glow-in-the-dark behavior, called bioluminescence! Naturally found in creatures such as fireflies and jellyfish, it is especially useful for protection, camouflage, or attracting mates.
Two of the most common phosphors found in glow-in-the-dark toys are zinc sulfide and strontium aluminate, which can be energized by normal light. They are mixed with plastic and molded into a desired shape. After being energized and placed in the dark, phosphors emit a glow, which is usually green, as they slowly release their stored energy. However, strontium aluminate is newer and has greater persistence, meaning it glows longer than zinc sulfide.
Other products that contain phosphors include TV screens, computer monitors, and fluorescent lights. Whereas the phosphors in TV screens and computer monitors are energized by an electron beam, the phosphors in fluorescent lights are energized by ultraviolet light.
Glow sticks also glow in the dark, but it is called chemiluminescence and are due to a chemical reaction rather than exposure to light.
Nature also exhibits glow-in-the-dark behavior, called bioluminescence! Naturally found in creatures such as fireflies and jellyfish, it is especially useful for protection, camouflage, or attracting mates.
http://wonderopolis.org/wonder/how-do-things-glow-in-the-dark/
http://science.howstuffworks.com/innovation/science-questions/question388.htm