Physics, science that deals with the interaction of matter and energy. Physics attempts to explain the nature of the physical world from the movements of planets to the smallest sub-atomic particles. Physics is important because many of the conclusions drawn from scientific study are applied to medicine and technology. Physics is usually divided into 2 large categories-classic physics and modern physics. Classic physics is primarily concerned with matter, motion, and energy. It can be subdivided into other areas of investigation which include mechanics, thermodynamics, acoustics, optics, and electromagnetism. The outstanding contributions to classical physics are found in the works of Archimedes, Copernicus, Galileo, Kepler, Descartes, Huygens, and Newton. Modern physics is primarily concerned with the structure of the physical world and contains a number of different disciplines including, atomic, nuclear, particle, solid state, and fluid physics. The major contributions to modern physics can be found in the works of Max Planck, Niels Bohr, and Albert Einstein, Enrico Ferni, Theodore H. Maiman, Murray Gell-Mann, George Zweig, Burton Richter, Samuel C.C. Ting, and Carl Rubbia.