Thanks to the WonderLab Museum of Science, Health and Technology in Bloomington for helping us with our science experiments!

Visit their web site to find out more about the WonderPage, hands-on science programs and exhibits at the museum, and birthday parties that rock.

If you’re in Bloomington you can visit WonderLab in person at 308 West Fourth Street.

Popcorn Science

Discover what makes a popcorn kernel unique from other kinds of corn kernels, and what makes a kernel pop!

What do we need?

• Popcorn kernels
• Sweet corn kernels
• Bowl of water
• Air popcorn popper

What do we do?

1. Soak one cup of popcorn kernels in water over night. Then drain the water and place them in the popcorn popper. Pop them for five minutes. What happens?
2. Next, place one cup of sweet corn kernels in one popper and one cup of popcorn kernels in another popper.
3. Turn on the poppers for five minutes. Observe.

What’s going on?

Popcorn comes from a popcorn plant, which is different than other kinds of corn plants. If you were to try to pop other kinds of corn kernels, like sweet corn for instance, they would not pop up like popcorn does.

The science behind popcorn is in the kernel. Kernels have three parts: the germ, which contains the corn oil, the endosperm, which contains the water and starch (and is the part of popcorn kernels that fluffs up when popped), and the hull, which is the hard outer covering that protects the kernel.

So how does a kernel become popcorn? Well, the water in the endosperm turns into steam when it is heated up. The hull traps this steam inside the kernel until the pressure is so great that it explodes and the kernel turns itself inside-out!

Sweet corn has a very thin hull, while popcorn has a very thick hull. When you try to pop sweet corn, the steam does not become pressurized enough to pop the kernels because the moisture seeps out of the hull. It just dries up in the popper!