What makes a glow stick glow?
A glow stick glows as the result of the chemical reaction between two liquids - the 'oxilate' typically trichloro-6-carbonpentoxyphenyl and phenylethynyl.
The chemical reaction for this kind of heatless light happens when you mix multiple chemical compounds. When you combine two or more compounds, the atoms may rearrange themselves to form new compounds. Depending on the nature of these compounds, this chemical reaction will cause either a release of energy or absorption of energy.
We know that we can activate a glow stick by bending and then shaking it. When you bend it, a very fragile glass vial inside of it breaks and releases the chemical inside (hydrogen peroxide) to mix with the other substance (phenyl oxlate ester).
When the two compounds are allowed to mix, they go through a chemical reaction (oxidation), which makes a different, unstable chemical, called peroxyacid ester. This new unstable substance decomposes into a different compound, (phenol and a cyclic peroxy compound) and then to carbon dioxide. The energy caused by the decomposition makes the particles in the fluorescent dye move faster and this creates light. The color of the fluorescent dye determines what color the light will be. The process by which this happens is called chemiluminescence.
What happens if you take 2 styrofoam cups and fill one with cold water and one with hot water and drop a glow stick in each?
The better question is does a glow stick glow longer in hot or cold environments. Here since its a chemical reaction heat acts as a catalyst and speeds up the process. So in warm weather you'll get brighter glow that lasts significantly shorter then a glow stick in a cold environment. Funny enough if you cool down a glow stick enough (about -60 F) then the process will stop altogether.
You can bring a dead glow stick back to life. Put the dead glow stick in the freezer, leave in there for at least 3 hours, then take the glow stick out and 1) put it in the microwave for 10-15 seconds no more than 25 seconds (may be dangerous) or 2) put them in a glass of hot/warm water until they start glowing again (safe). . You can repeat this process over and over…
No, a glow stick cannot be reused. When the stick is broken, the chemicals, which have been held separate, are released. They will mix and begin the reaction that releases the light. The reaction will continue until the chemicals are "used up" and the stick stops glowing. The light stick cannot then be reused.