Scientist. He was one of the most influential scientific figures in human history. He used the telescope to vindicate Copernicus and is remembered as the Father of the modern Experimental Science, as well as the Father of the Science of Motion. Born in Pisa, Italy, as a child he showed unusual skill with building block toys. As he grew into a teenager, he learned to play the lute and the organ, and won a reputation for his oil paintings. Galileo's father, a merchant and musician, encouraged his son to become a doctor, and Galileo studied medicine and philosophy at the University of Pisa. At the age of 20, he watched a lamp swing in the Pisa cathedral, and timing the motions with his pulse, realized that each swing took the same amount of time. This simple observation established the Law of Pendulum Motion, the principle behind making clocks accurate. Leaving the university for lack of money in 1585, Galileo abandoned medicine to study mathematics. Shortly afterwards, he invented the hydrostatic balance, an instrument used to find the specific weight of an object by weighing it in water. Returning to the University of Pisa in 1589, this time as a professor of mathematics, Galileo resumed his studies, and soon discovered the Law of Falling Bodies (sometimes called the Law of Gravitational Force), by dropping two identical sized objects of unequal weights from the leaning Tower of Pisa. When both objects hit the ground at the same moment, it demonstrated that gravity acted on both objects equally. Since this contradicted the teachings of Aristotle, who had stated that heavier bodies fall faster than lighter bodies, Aristotle followers forced Galileo to leave the University of Pisa and he soon joined the University of Padua, where he taught math for the next 18 years. Here he made his most important contributions to science, including inventing the sector (a type of navigational compass still used today), and several astronomical discoveries, including that four moons surround Jupiter, the nature of the Milky Way, and the rings around Saturn. Having named the first four moons of Jupiter for the politically powerful Medici family, Galileo was soon offered protection from the followers of Aristotle's thinking by Cosimo Medici, who offered him a position as his personal professor of mathematics in Florence. Galileo accepted and while in Florence, he discovered that both Venus and Mars had phases, and that the sun had sunspots. Showing his discoveries to Pope Paul V and other high church officials did not convince them, and soon the Catholic Church opposed him for supporting the Copernican system that the earth revolved around the sun. (Official church view at that time was that the earth was the center of the universe and the sun, planets, and stars revolved around a stationary earth. What those in the Catholic Church opposing Galileo had forgotten was that St. Thomas Aquinas, Doctor of the Church, taught that all truth related to objective observation, no matter where it was found, was verifiable. And if such truth was not verifiable, then it did not deserve the description of 'truth'.) In 1632, Galileo published his best written work, "A Dialogue on the Two Principal Systems of the World" in which he expressed his support for Copernicius against Aristotle. The Church Inquisition then tried him, and forced him to state that he had changed his mind; had he refused to recant, the penalty was death. The Church sentenced him to an indefinite prison term, but confined him to his villa in Florence. There he spent his last years writing on the laws of force and motion, publishing "Dialogues on the Two New Sciences" in 1638, which summed up his life's work on gravity, motion and acceleration, and furnished the basis for the three Laws of Motion laid down by Sir Isaac Newton in 1687. He was confined to his home until his death in 1642, but his contribution to science and the scientific method has reached through the succeeding years to this present day. Fifty years after his death, the city of Florence erected a monument in Galileo's honor at the church he attended.