|Popcorn or popping corn is a type of corn which puffs up
when it is heated in oil or by dry heat. Some natural types will pop, but
the cultivated strain is Zea mays L. subsp. mays (Everta Group), which is
a special kind of flint corn. It is a popular snack in the United States
and other countries, and is particularly common in movie theaters. It is
often served with butter and salt. It is also sometimes flavored with sugar
or spices. Special varieties of corn are grown to give improved popping
Popcorn balls (popped kernels stuck together with a sugary "glue") are a traditional Halloween treat. Cracker Jack is a popular, commercially produced candy that consists of peanuts mixed in with caramel-covered popcorn.
How Popcorn Pops
The folklore of some Native American tribes told of spirits who lived inside each kernel of popcorn. The spirits were quiet and content to live on their own -- but grew angry if their houses were heated. The hotter their homes became, the angrier they'd get -- shaking the kernels until the heat was too much. Finally they would burst out of their homes and into the air as a disgruntled puff of steam.
Each kernel of popcorn does contain a small drop of water stored inside a circle of soft starch. (That's why popcorn needs to contain 13.5 percent to 14 percent moisture The soft starch is surrounded by the kernel's hard outer surface.
As the kernel heats up, the water begins to expand, and pressure builds against the hard starch. Eventually, this hard surface gives way, causing the popcorn to explode.
As it explodes, the soft starch inside the popcorn becomes inflated and bursts, turning the kernel inside out. The steam inside the kernel is released, and the popcorn is popped.