Corn

Corn is a tall grass plant that people grow for its seeds, which are also called corn or kernels. In most countries outside the United States, it goes by the name maize. Corn was first grown by farmers in what is now Mexico about 9,000 years ago. Today it is the most-grown grain on Earth, ahead of rice and wheat.

A corn plant can grow taller than a basketball player. The seeds form on a thick part of the plant called an ear or a cob. Each ear is wrapped in green leaves called the husk. Long silky threads called silks hang out the top. Each strand of silk connects to one kernel. For a kernel to grow, a tiny grain of pollen has to land on its silk.

Corn did not always look the way it does now. Its wild ancestor is a grass called teosinte. Teosinte ears are tiny, with only about a dozen hard seeds. Native farmers in Mexico spent thousands of years choosing the biggest and best seeds to plant again. Bit by bit, the ears grew larger. Modern corn is so changed from its ancestor that it can no longer spread its own seeds. Without people to plant it, corn would not survive in the wild.

Corn was sacred to many Native peoples in the Americas. The Maya believed the first humans were made from corn dough. The Aztec, Hopi, Cherokee, and many other nations grew corn alongside beans and squash. The three plants were called the Three Sisters. The corn gave the beans something to climb. The beans put nutrients back into the soil. The squash leaves shaded the ground and kept it moist. Together they fed entire civilizations.

Today corn shows up in places you might not expect. Cornflakes, tortillas, popcorn, and corn on the cob are obvious. But corn syrup sweetens many sodas and candies. Cornstarch thickens soup. Corn feeds most of the cattle, pigs, and chickens that people eat. It is even turned into a fuel called ethanol that powers cars. The United States grows about a third of the world's corn, mostly in a region of the Midwest known as the Corn Belt.

Popcorn is a special kind of corn. Each kernel holds a tiny drop of water inside a hard shell. When the kernel is heated, the water turns to steam and bursts the shell open from inside. People have been popping corn this way for at least 5,000 years.