How does popcorn pop?

Pop! Pop-pop-pop! There is nothing quite like the sound of popcorn jumping in the pan. But how does a hard little seed turn into a fluffy white snack? The answer is a tiny bit of magic called steam.

A drop of water inside

Each piece of popcorn starts as a hard golden kernel. Hidden right in the middle of every kernel is a little drop of water. The kernel also has a tough, hard shell around the outside, like a strong little jacket.

Heat makes steam push

When you heat the kernels in a hot pan, the drop of water inside gets hotter and hotter. Soon it turns into steam. Steam is water that has become a gas, and it needs lots more room.

The steam pushes and pushes against the hard shell. The shell holds on as long as it can, but the pressure keeps building. At last — pop! — the shell bursts open.

Turning inside-out

When the kernel bursts, the soft, fluffy white inside puffs out and turns nearly inside-out. That fluffy puff is the popcorn you eat. The little pop you hear is the shell breaking and the steam rushing out.

Wonder fact: Popcorn can jump up to about 8 centimetres into the air when it pops — that’s like the kernel doing a tiny leap!