What Are "Old Maids"?: 8 Fun Popcorn Facts (Slideshow)

Each kernel of popcorn contains a small amount of water which, when heated, turns to steam. This steam builds pressure. When the pressure reaches about 135 pounds per square inch, the kernel will explode.

Popcorn Comes in Two Basic Shapes

Most popcorn comes in two basic shapes. The larger snowflake shape is used in ballparks and theaters, and the smaller mushroom shape is used for confections like caramel corn.

Only One Type of Corn Will Pop

There are six types of maize (pod, sweet, flour, dent, flint, and popcorn) but only popcorn, a.k.a. Zea mays everta, will pop when heated.

Popcorn Probably Wasn’t Served at the First Thanksgiving

Americans Eat Enough Popcorn to Fill the Empire State Building

Americans eat so much popcorn — more than fifty popped quarts per person per year — that it could fill the Empire State Building 18 times!

Popcorn is a Whole Grain

Though popcorn is often thought of as a snack food, it's also a whole grain. Without added butter, salt, or sugar, it can be a low-calorie, low-fat food.

Aztecs Offered Popcorn to Their Water god

Un-popped Kernels are Called “Old Maids” or “Spinsters”

Kernels that are too dry won't be able to create steam (or pressure) and won't pop. They're playfully called "old maids" or "spinsters."