Classical physics
theories of physics that predate modern, more complete, or more widely applicable theories / From Wikipedia, the free encyclopedia
Classical physics are the physics that were made before the 20th century. This part of physics studies things like movement, light, gravity, and electricity.
Most of physics today uses ideas that are more complicated than the ideas of classical physics, because in the 20th century, physicists discovered two better ways to describe nature: the theory of relativity and quantum mechanics.
Classical physics turned out not to work when the things being studied were very, very small (around the size of atoms or smaller), or were moving very, very fast (around the speed of light). So, around the beginning of the twentieth century, Albert Einstein worked out his Theory of Relativity and people like Neils Bohr, Werner Heisenberg. and Erwin Schrödinger created quantum mechanics.