Clay is soft, dense earth that can be shaped when wet and hardens when it dries or gets heated. If you've ever dug in muddy soil and found a patch that felt smooth and sticky, almost like natural Play-Doh, you've probably found clay.

People have used clay for thousands of years to make pottery, bricks, and sculptures. When a potter works at a spinning wheel, they're shaping wet clay into bowls, vases, or mugs. After the clay dries, it's fired in an extremely hot oven called a kiln, which transforms the soft material into hard, permanent ceramic that can hold water and last for centuries.

Clay comes in different colors depending on what minerals it contains: red clay gets its color from iron, while white clay (called kaolin) is prized for making fine porcelain. The ancient Greeks made clay amphoras to store olive oil. The Chinese perfected clay techniques to create delicate porcelain. Today, artists still work with clay, and factories use it to make tiles, bricks, and dishes.

In sports, a clay court is a tennis court covered with crushed brick or stone, giving the surface a distinctive red or green color. And when someone has feet of clay, it means they have a hidden weakness despite appearing strong or flawless.