Popcorn history is as interesting as the popcorn types and so the question – why does popcorn pop? Popcorn is a convenient short form of a variety of corn, which bursts from the kernel and puffs up when near a source of heat. The popcorn became a popular snack especially when watching movies in theatres, at a time when the United States was in the grip of the Great Depression.  The popping quality of the corn was first discovered thousands of years ago by the Native Americans. Some native tribes believed that when the corn popped, it was noise made by an angry god who escaped the kernel.