Galileo was a little different than the normal scientist of his time. Galileo was a rebel. He preferred to experiment and observe how things worked. He was always playing with pendulums, with balls rolling down inclined planes, with light and mirrors, and with falling bodies to see how things actually worked, not how they were thought to work. He was particularly interested in the motion of celestial bodies, and the natural laws relating to them.
Because of his propensity for experimentation and observation, Galileo is considered the father of modern experimental physics.