Microbiology is the study of living things too small to see with your naked eye. Microbiologists use powerful microscopes to examine bacteria, viruses, fungi, and other microscopic organisms that exist all around us and even inside us.

These tiny creatures have enormous effects on our world. Some bacteria help make cheese, yogurt, and bread. Others break down dead leaves in forests or help your body digest food. But microbiologists also study harmful microbes: the bacteria that cause strep throat, the viruses that cause colds and flu, and the fungi that cause infections.

Before microbiology developed as a science in the 1600s, people didn't know that invisible organisms caused diseases. They blamed bad smells or evil spirits instead. When scientists like Antoni van Leeuwenhoek first observed bacteria through early microscopes, they opened up an entirely new world. Later microbiologists like Louis Pasteur and Alexander Fleming discovered how to fight dangerous microbes, saving millions of lives.

Today, microbiologists work in hospitals identifying infections, in laboratories developing new medicines, in food companies ensuring safety, and even in environmental cleanup projects where bacteria can eat oil spills. They've discovered that a teaspoon of soil contains more microorganisms than there are people on Earth.