The greatest thing about science, to me, is learning how the world works. And chemistry is the ideal discipline to strike that perfect balance between being broadly applicable and fundamental enough to be able to predict how things will work…and why. I think when you know the language of chemistry, a whole new world opens up to you that you wouldn’t have been able to see at all before. Suddenly, once you understand chemistry, you want to know how everything around you works.
I always loved Pop Rocks as a kid, and never really understood how they work. After making a lot of baking soda and vinegar volcanos (which work by the neutralization of the acetic acid in the vinegar with the bicarbonate in the baking soda and forming
carbon dioxide gas), I just sort of assumed there was some reaction like that happening in Pop Rocks, even though they didn’t taste sour or tart, like an acid would.
Instead, Pop Rocks are actually a lot more unique than a simple acid-base neutralization reaction, like I’d initially thought.
Pop Rocks literally have carbon dioxide gas incorporated into them as they’re being made. In fact, the process has several patents on the technology, from the original patent, which was granted in 1961 to more recent ones that allowed for the process to be refined, to control the candy shape and the gas bubble size.
Pop Rocks are made by melting sugar and then pressurizing the container with the sugar melt with 600 pounds per square inch of carbon dioxide (about 40 times atmospheric pressure!). The carbon dioxide actually dissolves into the sugar. The sugar melt is allowed to cool to a temperature where it solidifies, and after it’s cooled, the pressure is vented. As your saliva (or any liquid) causes the sugar to dissolve, the gas bubbles are released, causing the popping sensation.
Pretty cool, huh?