Scientific activity of Galileo Galilei is considered the beginning of existence of physics as sciences in today's understanding of this word. Besides the fundamental opening, this great scientist invented and designed a set of applied devices.
Fundamental principles and laws of the movement
Two basic principles of mechanics are considered as the main opening of Galilei, they had considerable impact not only on development of mechanics, but also physics in general. The first of them - the principle of constancy of acceleration of gravity, the second - the principle of relativity for the uniform and rectilinear motion.
Besides these two principles Galileo Galilei opened laws of the constant period of fluctuation and addition of movements, inertia and free fall. He found the major regularities at the motion of bodies thrown at an angle and also at their movement on the inclined plane.
In 1638 the book by Galilei "Conversations and mathematical proofs" in which he stated the thoughts concerning laws of the movement in a matematizirovanny and academic form was published. Range of the problems considered in the book was very wide — from problems of a statics before studying resistance of materials and laws of the movement of the pendulum.
Invention of devices and astronomical opening
In 1609 Galilei created the device which is an analog of the modern telescope, the optical scheme in which convex and concave lenses were involved was its cornerstone. By means of this device the scientist watched the night sky. Subsequently Galilei made the telescope full for those times of this device. Galilei's observations changed the understanding about space existing in those days. He found out that the Moon is covered with mountains and hollows, before it was considered as smooth, opened phases of Venus and solar spots, specified that the Milky Way consists of stars, and Jupiter is surrounded with four satellites. Astronomical opening of Galilei, his conclusions and justifications resolved a dispute between supporters of the doctrine of Copernicus and Aristotle and Tolomeo's followers. It gave the obvious arguments showing that the ptolemeevsky system is wrong. In 1610 the scientist invented the return version of the telescope — a microscope, it just changed distance between lenses in the telescope which is already created by it. In 1592 Galilei designed a thermoscope — an analog of the modern thermometer, and after that invented a set of the major applied devices.
Creation of a method of experimenting
Besides the opening in physics and astronomy, Galileo Galilei became history as the founder of a modern method of experimenting. The scientist considered that for studying a certain phenomenon it is necessary to create a certain ideal world where this phenomenon is free from foreign influences. The ideal world has to be subject of further mathematical descriptions, and conclusions need to be verified with results of experiments in which conditions are as close as possible to ideal.