Popcorn, also known as popping corn, is a type of corn (maize) that expands from the kernel and puffs up when heated. Popcorn is able to pop because its kernels have a hard moisture-sealed hull and a dense starchy interior. When heated, pressure builds within the kernel, and a small explosion (or "pop") is the end result. Some strains of corn are now cultivated specifically for fine popcorn making.

It's important for corn to explode inside out in a proper way! Not every type of corn suits the recipe: the thickness of the outside layer and the amount of starch inside are important. One of the oldest forms of corn was found in Mexico, which is the evidence of popcorn cooking.