Bacteria

Bacteria are some of the smallest living things on Earth. They are so tiny that you need a microscope to see them. Bacteria live almost everywhere. They are in the soil, in water, and even inside your body.

Good and Bad Bacteria

Not all bacteria are bad. Many are helpful to people and the Earth. Some bacteria in your belly help you digest food. Others are used to make yogurt and cheese. But some bacteria can make you sick, like the ones that cause strep throat.

Tiny purple rod-shaped bacteria seen through a microscope.
Tiny purple rod-shaped bacteria seen through a microscope. (Dr Graham Beards / Wikimedia Commons)

How They Live

Bacteria are made of just one cell. They can split in two very quickly to make more bacteria. Some need air to live, and others do not. They can live in very hot or very cold places. Some even live in hot springs and the deep sea.

Fun Facts

  • There are more bacteria on your skin than people on Earth.
  • Soap and water wash away most bad bacteria.
  • Some bacteria can eat oil spills and clean up the ocean.

Did You Know?

Without bacteria in your gut, you could not digest some of the foods you eat.