Answer
When Galileo was young, one of his contemporaries used these words to describe Aristotle's idea of how objects fall:
There is a natural place for everything to seek, as:
Heavy things go downward, Fire upward,
And rivers to the sea.It was in the nature of falling, said Aristotle, that heavy objects seek their natural place faster than light ones -- that heavy objects fall faster.
Galileo took an interest in rates of fall when he was about 26 years old and a math teacher at the University of Pisa. It seemed to him that -- with no air resistance -- a body should fall at a speed proportional to its density. He decided to test this modified Aristotelian view by making an experiment.
There was no tradition of describing experimental research in Galileo's day. Controlled experiments were almost unknown. So Galileo's report was pretty skimpy. He seems to have dropped different balls from a tower. But what weights? What tower? We can be pretty sure it was the Leaning Tower of Pisa. But we end up doubting whether or not he really did the experiment. Maybe he just reported what he thought should have happened.
Explanation
