Microorganisms

microscopic · invisible life · disease and health · science discovery

Discovered by microscope. People suspected tiny invisible life existed for thousands of years, but nobody could prove it until Anton van Leeuwenhoek built one of the first microscopes in the 1670s and finally saw them.

They spoil our food. In the 1850s, scientist Louis Pasteur figured out that microorganisms were causing food to rot and go bad, which solved one of science's biggest mysteries at the time.

They cause diseases. In the 1880s, Robert Koch discovered that microorganisms were responsible for serious illnesses like tuberculosis, cholera, diphtheria, and anthrax, which helped doctors understand how sickness spreads.

Can be single or colonies. Microorganisms can live completely alone as just one cell, or they can team up with billions of other cells to form visible colonies, kind of like choosing between going solo or joining a band.