On Food and Cooking

essence of wintergreen and you get
something startling: a candy that seems to
give off sparks when you eat it! When
highly orderly sucrose crystals are
fractured between the teeth, the sudden
split leaves an imbalance of electrical
charge between the two pieces: there are
more electrons on one side than the other.
The electrons then jump the gap to the
more positively charged piece. En route,
they collide with nitrogen molecules in the
air, which then discharge the sudden jolt of
kinetic energy in the form of light energy.
The same kinds of electron jumping and
colliding produce lightning strikes between
electrically charged clouds and the earth.
Of course, sugar crystals give off a much
weaker glow than true lightning. And much
of that glow is in the invisible ultraviolet
part of the light spectrum. Here’s where
the wintergreen plays a role. Its aromatic
essence, methyl salicylate, is fluorescent: