The other was about his studies of the centers of balances of several different solids. With people respecting his work more, his reputation as a mathematician and physicist got him a teaching job at the University of Pisa in 1589. He soon began arguments, with commonly accepted science, by pointing out mistakes in the science and mathematics of that day. .

             To prove the common theory of gravity , Galileo dropped weights from the Leaning Tower of Pisa to prove his view of falling bodies. The law of falling bodies states, ³In the absence of air the speed of a falling body depends only on the time of the fall. The speed of the body does not depend on the body's weight.² He determined that Aristotle¹s law of falling bodies was false. Aristotle's law said that the weight of the objects directly determined how fast the object fell through the air. .

             Because of growing anger against him and his theories that weren¹t in keeping with commonly accepted sciences, Galileo was driven out of Pisa in 1591. Also in 1591, Galileo¹s father died and he had to support his mother, brothers, and sisters. He got a new job at the University of Padua, part of the Venetian Republic. His 18 years there were his ³happiest of his life.² He visited Venice several times during his years as a professor at the University. In 1604 Galileo gave a lecture in Venice that a new star which appeared earlier that year was major evidence to support the new doctrine of Copernicus. He also argued that the new star went against everything the Aristotelian doctrine of the heavens said. .

             Galileo also wrote a letter that year that contained his findings on the law of free fall. In this letter, he stated that ³the distances covered in equal times are proportional to the squares of the number of time intervals, and therefore, the distances covered in equal times are as the odd numbers beginning from one. ³ By natural motion, Galileo meant the body falling without resistance.