What’s with the popcorn kernels that don’t pop?

Question

I have no idea what the right flair for this is, sorry.

In: Physics

Answer 1

Popcorn kernels pop because they absorb heat energy until they reach a critical level and pop. When there are lots of unpopped kernels, most of the heat energy gets absorbed by the kernels. But when most of the kernels have popped, less energy gets taken in by kernels. The heat levels haven’t gone down though, so the excess heat energy goes into the already popped kernels more and more. At a certain point the popped kernels start to burn. Since you don’t want burnt popcorn, you stop the cooking before that happens.