HOW DOES IT WORK?:
Pop rocks candy “pops” because of the CO2 contained inside of them that is released when mixing the candy with water.
The baking soda (sodium bicarbonate) reacts with the contained CO2 as well to rapidly expand and rise. The lemon juice, which contains citric acid, breaks down this process to cause the “fizz.”
For full directions and more experiments and activities to try at home, visit https://www.putnam.org/pop-rocks.
If you try this at home, let us know how it went in the comments.