What Causes the ‘Pop’ of a Popcorn Kernel?

A popcorn kernel pops because steam inside it turns into hot air and makes it explode like a tiny balloon.

Inside every popcorn kernel is water trapped in a hard shell called the endosperm. When you heat up the kernel, that water starts to boil and becomes steam, think of it like turning a kettle on.

As the steam builds up, it pushes against the shell harder and harder. Eventually, the pressure gets so strong that the shell can't hold in any more steam. Boom! It bursts open, and the kernel expands into fluffy popcorn, just like when you blow up a balloon too much and it pops!

The hot air from the steam keeps the popcorn nice and warm, and that’s why we love eating it straight out of the bag! A popcorn kernel pops because steam inside it turns into hot air and makes it explode like a tiny balloon.

Inside every popcorn kernel is water trapped in a hard shell called the endosperm. When you heat up the kernel, that water starts to boil and becomes steam, think of it like turning a kettle on.

As the steam builds up, it pushes against the shell harder and harder. Eventually, the pressure gets so strong that the shell can't hold in any more steam. Boom! It bursts open, and the kernel expands into fluffy popcorn, just like when you blow up a balloon too much and it pops!

The hot air from the steam keeps the popcorn nice and warm, and that’s why we love eating it straight out of the bag!