- Wintergreen mints of all types emit light when the candy is bitten into. The light may be very faint, but it can occasionally be spectacular. The effect, called triboluminescence, is due to the electrical charge that builds up within the crystalline structure of the sugar within the candy. The triboluminescence occurs when the electrical charge is violently released as the structure of the crystals is broken. Of course, it isn't just sugary candies that produce this light; when anything is torn or broken, the same thing can occur. When atoms are forced violently apart, they lose a larger portion of their electrons far more quickly than normal. As the electrons search for balance, they bounce around until they find somewhere to rest.
- When the atoms are crushed, the electrons are forced out of their atomic orbits. These electrons collide with air molecules and the electrons transfer a portion of their energy in the collision. Because there is an excess of energy, a portion of that energy is emitted as visible light. With wintergreen mints, this visible light is bright blue, and while there isn't very much of it, it is extremely bright. The more pieces of candy that are crushed at one time, the greater the amount of atomic damage, and the more spectacular the light show. Wintergreen mints will emit a greater than normal amount of visible light because the wintergreen oil is fluorescent. The oil within the candy emits the light that is of a longer wavelength, and more easily seen by the human eye. The interesting thing about the wintergreen oil is that it absorbs the shorter wavelength light that is typically emitted and emits the longer wavelengths in its place. That's why the wintergreen candies will emit a much stronger "spark" than other candies.
- It's possible to recreate this in any dark room, but the candy must be fresh, and must have absorbed as little moisture as possible. Because it's absolutely necessary that the candy remains very brittle, individually-wrapped pieces of candy are far more likely to produce the tell-tale spark than those that have been packaged en masse.
