Popped corn was known to the native population of the Americas for thousands of years, in fact popping may be the way the grass ancestral to corn was originally prepared for eating. A hard "flint corn" variety is used, dried to the right moisture content. To pop it, it simply needs to be heated by some means until the internal steam pressure builds up and explodes the hull. The starch within has become gelatinized, but upon expanding it solidifies into a foam. The photo specimens were from Turkey, purchased at one of the local multi-ethnic markets in Los Angeles. The kernels were about 0.33 inches long, and popped very well.
Popcorn is often caramel coated, but this adds a lot of sugar to an otherwise healthy low calorie snack. Popcorn sold by movie theaters is horrifyingly calorie intensive. It's popped in coconut oil, which is not a big problem, but then it's saturated with melted butter, margarine and/or who knows what else. A small movie popcorn is likely to contain as much fat as three Big Mac hamburgers. Popcorn purchased pre-popped in bags is likely to be high in trans fats or, even worse, the interesterified fats increasingly used for "trans fat free" processed foods.
More on Corn.
Buying & Storing: Corn for home popping is sold in most markets in North America. Of course there are "gourmet" varieties available on the Internet, and they come in various colors, but the popped corn will still be the same color as from yellow corn.
Popping corn is sold in two basic varieties:
Popcorn should be stored in a sealed airtight container, away from heat and light, and for less than a year as it will not expand well if it becomes too dry.
Equipment: Many varieties of home popcorn poppers are sold. The Lehman's Stainless Stovetop Popper (US $54.95) is a highly regarded traditional popper, but I've found no special popper at all is needed, and I don't have the storage space for one anyway.
Cooking: Here's how I do popcorn: