Popcorn (also called popped corn, popcorns or pop-corn) is a variety of corn kernel which expands and puffs up when heated; the same names also refer to the foodstuff produced by the expansion.

A popcorn kernel's strong hull contains the seed's hard, starchy shell endosperm with 14–20% moisture, which turns to steam as the kernel is heated. Pressure from the steam continues to build until the hull ruptures, allowing the kernel to forcefully expand, to 20 to 50 times its original volume, and then cool.

Corn was domesticated about 10,000 years ago in what is now Mexico. Archaeologists discovered that people have known about popcorn for thousands of years. Fossil evidence from Peru suggests that corn was popped as early as 4,700 BC.

Popcorn is a popular snack food at sporting events and in movie theaters, where it has been served since the 1930s.

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