Physics the basic science that underlies all the natural sciences. And it is a search for the basic rules of the behavior of matter and energy on every scale: from the interaction of subatomic particles, to the motion of every day objects, to the evolution of galaxies and the universe itself. Physics consists of many fields, including particle and nuclear physics, atomic and molecular spectroscopy, optics, solid-state physics, biological and medical physics, computational physics, acoustics, astrophysics and cosmology.