Popcorn is a tasty snack to make while having a movie night at home, and its noisy popping sounds make it especially fun for the little ones. By now you’re probably used to the popping noise of popcorn, but have you ever wondered how this happens? What is it that makes popcorn pop, while corn on the cob simply cooks?

On the inside, popcorn kernels are filled with oil, water, and starch, and the outside is covered with a protective shell. Heating popcorn—say, in the microwave—causes the liquids inside to expand into steam. Because the hard outer coating leaves nowhere for the steam to go, it simply gets hotter and hotter inside of the kernel until it eventually reaches 365 degrees, which is hot enough to burst through the shell! The action of the starch and oil expanding so quickly and with so much heat transforms the mixture into the familiar foam-like puff that we eat as popcorn.

The next time you make a bag of popcorn at home, examine the kernels and think of the science behind your favorite movie snack!

What Makes Popcorn Pop? [Popcorn.org]
Why Does Popcorn Pop? [Tell Me Why Facts]
Why Does Popcorn Pop? [Mental Floss]
How Popcorn Pops [About.com]

CC-BY-SA-2.0/Flickr/cyclonebill