Galileo (1564-1642)

    Galileo was the first truly modern scientist. He made important advances in both astronomy and mechanics, but his greatest achievement was the creation of the experimental-mathematical method that has lain at the basis of all progress in physical science since his time.

     He was intelligent boy, very skilled at drawing and music. He spent his spare time making mechanical toys.

     Shortly after he began studying medicine at Pisa University he made his first scientific discovery, which is that the swing of a pendulum takes the same time, whether it swings in a large arc or in a small one. when he was 25 he was appointed as a professor of mathematics at Pisa. Galileo was the scientist who said that, apart of the effect of the air resistance, the heavy and the light weights fall at the same speed. He invented a mathematical instrument for simplifying the calculations of gunners, and others. He also invented

an air thermometer. Galileo was able to use the theory of optics to design a telescope. He found new stars and the planet Jupiter had 4 moons.

     In addition, Galileo was threatened of torture, if he didn't stop teaching his theory that said the earth goes round the sun not the opposite.

     In 1638, when he was 74,he published his greatest book, dialogues concerning two sciences; the first explains how the strength of a beam varies with its length, breadth, thickness, and the second with the behavior of moving bodies.

     In the 17th century, Galileo and others discovered that in a void all falling objects have the same constant acceleration, so that their motion may be determined by using the Merton rule. This result, however, did not resolve the question of motion of an object falling in air. The need for mathematical descriptions of such phenomena contributed to the development of the concept of derivative.