When you think about it, we take for granted that some things just happen. The sun will rise in the morning, you’ll get hungry at lunchtime, and your dog will do his business on the lawn. But if you look back just a few centuries, people believed that a lot of these things were not only spontaneous—they were created by invisible spirits!
Like lots of other scientists of his day, Francesco Redi was interested in how things work naturally. He had heard a rumor that maggots were spontaneously generated from meat, which is what led him to conduct his famous experiment: he sealed pieces of meat in jars with no openings and left them there for months at a time. When he opened the jars later on, he found that no maggots had grown. This proved without a doubt that maggots are not spontaneously generated from meat—they come from fly eggs!
This discovery was an important step forward in science because it showed us how important it is to conduct experiments when trying to figure out how something works. It also helped us understand how important it is to keep our experiments carefully controlled so we can draw conclusions about what causes what effects on our world—and what doesn’t cause any effects at all!
