(WFRV) – Pop-Rocks is common candy that gives many kids joy with the crackling sound they make in your mouth.

But what creates the popping sound?

Each of the tiny rocks contains compressed carbon dioxide. Once the pop-rocks come into contact with moisture, such as the saliva in your mouth, the carbon dioxide is released, giving off the popping sound.

In the Earth’s atmosphere, carbon dioxide is a greenhouse gas that acts to keeps the planet warm. It is also a common molecule when talking about the reasons behind climate change.

Try it Yourself Experiment:

In this experiment a Pop-Rock – soda reaction will cause a balloon to inflate.

Materials: A balloon, one 20 ounce liter of soda, and one bag of Pop-rocks.


  1. Pour one bag of Pop-Rocks into the deflated balloon
  2. Open the liter of soda and gently dumb the Pop-Rocks into the soda with the balloon covering the lid
  3. The Pop-Rocks will dissolve the soda and inflate the balloon

What causes the balloon to inflate?

The soda also contains pressurized carbon dioxide and when the Pop-Rocks are dropped into the soda some gas in the soda collects in the bubbles caused by the Pop-Rocks. Those bubbles move upward and inflate the balloon.

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