©iStockphoto.com/Razvan Quantum physics, a term considered interchangeable with "quantum mechanics," deals with matter and energy at the smallest scale available: the atomic and subatomic realms. Up Next Can your hair turn white overnight? Is Chicago the windiest city in the U.S.? Is Seattle the rainiest city in the U.S.? Should you wear light-colored clothes in hot weather to stay cool? Can a penny dropped off a building kill you?