Pop Rocks candy works by creating a rapid expansion of carbon dioxide gas bubbles when it comes into contact with moisture, such as saliva. The popping sensation is caused by the sudden release of pressure as the gas bubbles burst, creating a fizzing sound and a tingling sensation in the mouth.

Pop Rocks candy is made with a mixture of sugar, corn syrup, lactose, and baking soda. The baking soda is what causes the reaction when the candy comes into contact with moisture. When the candy is eaten, the saliva in the mouth dissolves the sugar and corn syrup, creating a liquid solution that contains the baking soda. The baking soda then reacts with the acid in the saliva to produce carbon dioxide gas bubbles, which cause the popping sensation.

The amount of popping that occurs in a piece of Pop Rocks candy depends on the amount of saliva that it comes into contact with. If the candy is chewed or sucked on, it will produce more pops than if it is simply swallowed. Pop Rocks candy is also more likely to pop in warm, humid environments, as the higher temperature and humidity increase the amount of moisture that is available to react with the baking soda.

Pop Rocks candy was first introduced in the United States in the early 1970s and quickly became a popular treat due to its unique popping sensation. It has since been enjoyed by people of all ages and is a common treat for parties and other special occasions.