system
Given the following post, respond as if you're commenting on Reddit:
human
How do "pop rocks" candies work?
gpt
Tiny bubbles.

The candy is made by making a hot syrup of melted sugar and flavorings, and then mixing it with high-pressure carbon dioxide. As the foamy mixture cools and hardens, lots of tiny gas bubbles become trapped inside, still at high pressure.

When you eat the candy and it starts to dissolve, those bubbles pop. The release of pressurized gas is what makes the rocks fizz in your mouth.