Welcome to The Sound of Science from WNIJ and NIU STEAM. It’s a weekly series explaining important STEM concepts. Today’s hosts are Jeremy Benson and Newt Likier.
On today’s segment, five-year-old Marcus has popped the question: Why doesn’t corn on farms turn into popcorn on really hot days?
If you’ve ever had steaming popcorn fresh from the microwave, you know it takes a lot of heat to turn those hard little kernels of corn into the fluffy popcorn we all know and love. It can get pretty hot under the summer sun, but Marcus has correctly noticed that all the fields of corn around us remain sadly unpopped.
Before we get too far, it should be noted that not every type of corn is the right type for popping. You could do everything else right, but if it’s not the right species, you won’t get the tasty treat you’re expecting.
The corn we grow in and around DeKalb is mostly field corn, which is used for things like ethanol and livestock feed, so it’s not ideal for popping. But somewhere there must be whole fields of popcorn corn, right? Could they ever just spontaneously start to pop?
Let’s think about how popcorn works. Each kernel is a seed, and inside that seed is a tiny bit of water. Popcorn works by heating that water until it turns to steam, which then rapidly expands blowing the kernel inside out. That means the kernels need to reach 100 degrees Celsius, or 212 degrees Fahrenheit before they’ll pop. Even the inside of a sealed car in direct sunlight doesn’t get that hot, and the corn’s husk helps keep the kernels cool even on the hottest days.
Aw shucks, so that’s why they don’t pop. I really wanted to see a field of popping corn.
Shucks? That was pretty corny, Newt.
Speaking of corn, don’t forget to stop by NIU STEAM’s booth at Corn Fest this weekend.
And I’ll be doing a STEAM demo show on the community stage at The Egyptian Theater. We hope to see you there!
If there’s anything you want to learn about the world, we’ve got an ear out for your questions at niusteam@niu.edu.
This has been the Sound of Science on WNIJ. Where you learn something new every day.
