Popcorn or popping corn is a type of corn, which explodes from the kernel and puffs up when heated. Corn popping was originally discovered by Native Americans, but became popular as a snack food during the United States Great Depression, especially in movie theatres.

Corn is able to pop because, unlike other grains, its kernels have a hard moisture-sealed hull and a dense starchy filling. This allows pressure to build inside the kernel until an explosive "pop" results. Some strains of corn are now cultivated specifically as popping corns.

There are many techniques for popping corn. Commercial large-scale popping machines were invented by Charles Creators in the late 19th Century. Many types of small-scale home methods for popping corn also exist, with the most popular being prepackaged microwavable popcornFact: date=March 2009.

As a snack food, popcorn has both advocates and detractors. Some consider it to be a health food, while others caution against it for a variety of reasons. Popcorn can also have non-food applications, ranging from holiday decorations to packaging materials.

History

Popcorn was first discovered thousands of years ago by the Native Americans , who believed that the popping noise was that of an angry god who escaped the kernel.

During the Great Depression, popcorn was comparatively cheap at 5-10 cents a bag and became popular. Thus, while other businesses failed the popcorn business thrived and became a source of income for some struggling farmers. During World War II, sugar rations diminished candy production causing Americans to eat three times more popcorn than they had before.

At least six localities (all in the United States) claim to be the "Popcorn Capital of the World": Valparaiso, Indiana; Van Buren, Indiana; Marion, Ohio; Ridgway, Illinois; Schaller, Iowa; and North Loup, Nebraska. According to the USDA, most of the maize used for popcorn production is specifically planted for this purpose; most is grown in Nebraska and Indiana, with increasing area in Texas.

As the result of an elementary school project, popcorn became the official state snack food of Illinois.

How popcorn pops

As the oil and the water are heated past the boiling point, they turn the moisture in the kernel into a superheated pressurized steam, contained within the moisture-proof hull. Under these conditions, the starch inside the kernel gelatinizes, softening and becoming pliable. The pressure continues to increase until the breaking point of the hull is reached: a pressure of about 135 psi (930 kPa) and a temperature of . The hull ruptures rapidly, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into airy foam. As the foam rapidly cools, the starch and protein polymers set into the familiar crispy puff.