Einstein's Special Theory of Relativity - the connection Einstein discovered between energy and mass is expressed in the equation E=mc²
Welcome to the Physics page. This guide will help you locate information resources in Physics.
Physics (from Ancient Greek: φύσις physis "nature") is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.
Classical physics became a separate science when experimental and quantitative methods were used to discover what are now considered to be the laws of physics. Kepler, Galileo and more specifically Newton discovered and unified the different laws of motion. Classical physics includes the traditional branches and topics that were recognized and well developed before the beginning of the 20th century—classical mechanics, acoustics, optics, thermodynamics, and electromagnetism.
Modern physics is concerned with the behavior of matter and energy under extreme conditions or on the very large or very small scale. Albert Einstein contributed the framework of special relativity, which replaced notions of absolute time and space with spacetime and allowed an accurate description of systems whose components have speeds approaching the speed of light. Max Planck, Erwin Schrödinger, and others introduced quantum mechanics, a probabilistic notion of particles and interactions that allowed an accurate description of atomic and subatomic scales.