What causes Pop Rocks to explode?

Pop Rocks hit candy aisles in 1975 and immediately sent kids into a frenzy with their explosive mouth fireworks. General Foods (specifically William A. Mitchell) figured out that by blasting melted sugar with CO2 at extreme forces and then rapidly cooling it, you could trap that gas inside little sugar pockets. Any contact with liquids, like your saliva, causes the sugar to melt and the CO2 to escape in thousands of rapid-fire bursts. There's a myth that mixing Pop Rocks with soda might cause your stomach to explode. But don't worry, that rumor was probably just started by a parent worried about a bunch of kids with a sugar rush.