Why Do Wint-O-Green Life Savers Spark in the Dark?

Roll of Life Savers
A roll of Life Savers is seen in a grocery
Tim Boyle/Getty Images

Actually, all hard sugar-based candies emit some degree of light when you bite them, but most of the time, that light is very faint. This effect is called triboluminescence, which is similar to the electrical charge build-up that produces lightning, only much less grand. Triboluminescence is the emission of light resulting from something being smashed or torn. When you rip a piece of tape off the roll, it will produce a slight glow for the same reason.

Triboluminescence occurs when molecules, in this case crystalline sugars, are crushed, forcing some electrons out of their atomic fields. These free electrons bump into nitrogen molecules in the air. When they collide, the electrons impart energy to the nitrogen molecules, causing them to vibrate. In this excited state, and in order to get rid of the excess energy, these nitrogen molecules emit light -- mostly ultraviolet (nonvisible) light, but they do emit a small amount of visible light as well. This is why all hard, sugary candies will produce a faint glow when cracked.

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But when you bite into a Wint-O-Green Life Saver, a much greater amount of visible light can be seen.

This brighter light is produced by the wintergreen flavoring. Methyl salicylate, or oil of wintergreen, is fluorescent, meaning it absorbs light of a shorter wavelength and then emits it as light of a longer wavelength. Ultraviolet light has a shorter wavelength than visible light. So when a Wint-O-Green Life Saver is crushed between your teeth, the methyl salicylate molecules absorb the ultraviolet, shorter wavelength light produced by the excited nitrogen, and re-emit it as light of the visible spectrum, specifically as blue light -- thus the blue sparks that jump out of your mouth when you crunch on a Wint-O-Green Life Saver.

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Originally Published: Nov 3, 2000

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Life Savers FAQ

What company makes Life Savers?
Mars Wrigley makes Life Savers, which is the same company that makes Snickers, Skittles, M&Ms, and Orbit chewing gum.
What are the flavors of Life Savers?
The flavors that are currently widely available are cherry, raspberry, watermelon, orange, pineapple, Wint-o-Green, pep-o-mint, and buttered rum.
How many different flavors of lifesavers are there?
More than 40 flavors of Life Savers have been created since they were invented in 1912, though many have been discontinued over the years and other new flavors have been introduced.
Do Life Savers spark in your mouth?
All hard sugar-based candies emit some degree of light when you bite them, but most of the time it's faint. This is due to triboluminescence, which is the emission of light resulting from something being smashed or torn. If you do this to a Wint-O-Green Life Saver, you can see a much greater amount of light (blue sparks!) due to the wintergreen flavoring or methyl salicylate. Try it yourself!
Did Creme Savers get discontinued?
Yes, Creme Savers — a spinoff candy of Life Savers — were produced in the late '90s in strawberry and orange flavors. Sadly, the candy was discontinued mid-00s without a clear explanation.