are there little batteries in there??
In: Chemistry
It uses something called photoluminescence, basically during periods of bright light it absorbs the energy from the light only to release that energy back later when it is dark.
You know fluorescent lights? They work by absorbing electricity and emitting it another way, as visible light. You electrify the gas and it glows.
Glow-in-the-dark works via a mechanism called phosphorescence. It’s a lot like fluorescent bulbs: they absorb UV and high-frequency light, and re-emit it as lower-frequency visible light. The difference is that because of the chemical structure of the substance, an electron that gets absorbed by it gets “trapped” and it takes some time for the electron to escape. This is what gives it the time-delay quality unlike fluorescence: the re-emitted light comes seconds/minutes/hours after being exposed to light.
And this is all different than chemiluminescence: what glow sticks do.
Material absorbs light power, which makes the material all excited. Problem is, material wants to relax, so it “works off” the extra power by letting the extra power back out as light.
More complex: It’s all to do with electron energy states. Phosphorescent materials (like Zinc Sulphide) have multiple energy states that have a lot to do with the electron energy itself. Remember, things want to be in the lowest stable energy. By adding energy of a particular wavelength (For example, most “green” glow in the dark materials need to be charged by blue or higher light) we can push those electrons up higher. When they drop back down, the energy MUST be released somehow, and in this case it’s released as a photon of light. Coincidentally, the requirement for energy is why if you shine a red laser on a “green” glow object it doesn’t stay glowing anywhere near as long.
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