Popcorn,  or pop corn, is a variety of corn kernel, which forcefully expands and puffs up when heated. A popcorn kernel's strong hull contains the seed's hard, starchy endosperm with 14-20% moisture, which turns to steam as the kernel is heated over this stove (as seen above). The pressure continues building until it exceeds the hull's ability to contain it (i.e. trouble). The kernel ruptures and forcefully expands, allowing the contents to expand, cool, and finally set in a popcorn puff 20 to 50 times the size of the original kernel.[1] Some strains of corn (taxonomized as Zea mays) are cultivated specifically as popping corns. The Zea mays variety everta, a special kind of flint corn, is the most common of these. bye.