Six Core Theories of Modern Physics
- Classical mechanics is the study of how energy and force influence the motion of physical objects, including gases, liquids and solids. It is also known as Newtonian mechanics. It was Newton's book "Principia" that outlined the basic laws of motion. Physicists prefer to use classical mechanics to explain the movement of solids at equilibrium or rest, when force is added to a solid to make it move or without concern for the reason why the solid has moved.
Electricity and Magnetism
- Michael Faraday, a 19th-century English chemist and physicist, is credited with perfecting experiments dealing with electromagnetism. He proved that when metals carry an electrical current, they act as magnets to other nearby metals. This function is important for the electric motors in many apparatuses we use today. Faraday also established that electricity and magnets are sources of light energy because, when combined, magnets and light rays create imperceptible waves, producing what we know as X-rays, gamma rays and radio waves.
- This branch of physics explains the mathematical structure of atoms and molecules and how subatomic particles behave. It also explains how crystals, nuclear energy and chemical bonds work. Niels Bohr, Max Planck, Werner Heisenberg and a number of other prominent 20th-century physicists made significant contributions to this field. As a result of this theoretical work, the laser, the electron microscope and the transistor were invented.
- Statistical physics, also known as thermodynamics, uses probability theory and statistics to explain the behavior of large groups of particles instead of that of individual particles. It has important applications in fields such as mechanics, chemistry, biology and even sociology.
- Developed by Albert Einstein, special relativity states that the speed of light coming from a source is always the same, no matter how fast or slow that source or the observer of the source is moving. Also known as the theory of space and time, it further theorizes that all the laws of physics are equal.
Quantum Field Theory
- Based off of Einstein's theory of relativity, this branch of physics uses the theory of fields to describe why particles operate the way they do, especially when they are created or destroyed. An example of a field is an electromagnetic field. Quantum physics seeks to explain how atoms emit light and how electrons and other particles jump from one condition to another.