Many Divisions of Physics

There are no exact differences between physics and other natural sciences because all sciences overlap. In general, however, physics is the scientific study of forces and qualities such as heat, light, sound, pressure, gravity and electricity, and the ways they affect other objects.

One major branch of physics deals with the states of matter—solids, liquids, and gases—and with their motions. The pioneer achievements of Galileo, Kepler, and Newton dealt with solid masses of matter in motion. Such studies deal with forces acting on moving objects. It is the subject of mechanics and belongs to the branch of mechanics called dynamics, the study of matter in motion. This large topic includes not only the motions of stars and ping-pong balls but also the motions of the water pumped by a fire engine and those of the air passing through the jet engine of an airplane.

A branch of mechanics is statics, the study of matter at rest. The design of buildings and bridges are examples of problems in statics. Other branches of physics are based on the different kinds of energy which interact with matter. They deal with electricity and magnetism, heat, light, and sound. From these branches of physics scientists find clues which have revealed the constructions of atoms and how the atoms react to various kinds of energy. This knowledge is often called the basis of modern physics. Among the many subdivisions of modern physics are electronics and nuclear physics. Physics is closely related to engineering. A person who uses knowledge of physics in solving everyday problems is often called an engineer. For example, electricity is one of the branches of physics, and an electrical engineer is a man who uses the "natural laws" of electricity to help in designing an electric generator.