Pop Rock Explosion
License: CC BY-NC 3.0
Yum! Rock candy. Actually, it’s pop rock candy. It pops and fizzes as it melts in your mouth. Do you know why?
The Back Story
- The reason pop rocks pop is that they release gas as they melt. The gas is under pressure in tiny bubbles inside the candy.
- The gas is carbon dioxide, the same gas that fizzes out of soda (pop) when you open the can.
- How much pressure is the gas under in pop rocks or soda? There’s a widespread myth that if someone swallowed enough pop rocks and soda, the pressure of all that gas could cause the stomach to explode.
- The Mythbusters TV show investigated this myth, as you can see in this video: http://www.youtube.com/watch?v=93vjY9RY4-k
- Watch this video to see how you can do a similar pop rocks experiment: http://www.youtube.com/embed/WNVnQwvRgyI?autoplay=1&wmode=opaque
Can You Apply It?
At the link below, learn more about pop rocks. Then answer the following questions.
- How are pop rocks made? How does high-pressure gas get inside the candy?
- Gas always moves from an area of higher pressure to an area of lower pressure. How does this apply to the gas in pop rocks?
- Describe the experiment the Mythbusters did to answer the question: Can pop rocks and soda cause the stomach to explode? What was the result of the experiment?
- How does gas pressure explain what you observed in the Mythbusters’ experiment?