Popcorn is the oldest of three types of corn - field corn (fed to animals), sweet corn (fed to humans), and popcorn. It was discovered by Indian Americans many thousand years ago. In Bat Cave, a small cave in New Mexico, people 5,600 years ago made popcorn. Archaeologists found some unpopped kernels and they were still able to pop them. Popcorn (the plant) is 4-6 feet tall and very small, at least compared to other types of corn which sometimes grow to twenty feet.
Many methods were tried to find the best way to cook the popcorn. An ear of corn was held over the fire. Most kernels fell into the fire through this way. Another idea was to throw kernels into a fire, by the handful. Popcorn was exploding everywhere, so this was obviously not the best method. In 1612, French explorers observed Indians using clay pots, filled with hot sand, to pop the corn. When the corn popped, it submerged from the sand and was easy to collect.
Today, contrary to popular belief that popcorn is only for the movies, 60%, of the 500,000,000 pounds of popcorn eaten by Americans, is popped in homes. Most popcorn is grown in the Midwestern United States. The popcorn's outer layer is called the endosperm, which contains starch and protein. About 4% of the kernel is oil, though. Underneath that is the embryo, which contains the plumule, a small bud, and the seed leaf, also called the cotyledon. The female popcorn plants receive pollen grains from the male, and this fertilizes their ovaries into kernels.
When the kernels are heated up, the heat changes the moisture inside the kernel to steam. The pressure of the steam becomes immense so the cover breaks and the plant's food (mainly starch) pops out. This soft, white substance is what is so commonly called popcorn. The Indian people, however, developed a legend to explain the popping corn kernels. According to them, the kernel was a little house containing a demon. When the demon got very mad, he exploded.
There are several types of popcorn. White and yellow hull-less are the most common ones. The largest kinds are called "Dynamite and Snow Puff." There are several kinds of black kernels, however they pop white. Another smaller kind of kernel is called "strawberry" because its kernels are red. "Rainbow" corn-on-the-cobs have several different color kernels on them - usually red, white, yellow, and blue. Popcorn is a very interesting topic.