Here's what he did:
* The Question: At the time, people believed in spontaneous generation - the idea that life could arise from non-living matter. For example, some believed flies could spontaneously arise from rotting meat.
* Redi's Experiment: He placed meat in several jars.
* Some jars were left open to the air.
* Others were sealed shut.
* Others were covered with a fine cloth that allowed air in, but kept flies out.
* The Results: Flies appeared only in the jars that were open to the air. The jars that were sealed or covered with cloth remained fly-free, even when the meat rotted.
* The Conclusion: This experiment strongly suggested that flies don't spontaneously appear from rotting meat, but rather come from other flies. This was a significant step in challenging the theory of spontaneous generation.
Let me know if you have other questions!