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 size, and then cool. 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. Traditions differ as to whether popcorn is consumed as a hearty snack food with salt (predominating in the United States) or as a sweet snack food with caramelized sugar.
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