To better understand controlled experiments, let's look at Francesco Redi's famous controlled experiment on maggots and meat as an example. Francesco wanted to find the answer to the question, "Do maggots (flies) come from rotting meat?". This may seem like a really silly question, but in Francesco Redi's day (1600s), people actually believed that flies and maggots were generated spontaneously from meat. Take a look at Redi's experiment below.