physics, physical science, natural philosophy

the science of matter and energy and their interactions

• acoustics — the study of the physical properties of sound
• astronomy, uranology — the branch of physics that studies celestial bodies and the universe as a whole
• aeronautics, astronautics — the theory and practice of navigation through air or space
• biophysics — physics as applied to biological problems
• cryogenics, cryogeny — the branch of physics that studies the phenomena that occur at very low temperatures
• crystallography — the branch of science that studies the formation and structure of crystals
• electromagnetism, electromagnetics — the branch of physics concerned with electromagnetic phenomena
• electronics — the branch of physics that deals with the emission and effects of electrons and with the use of electronic devices
• electrostatics — the branch of physics that deals with static electricity
• mechanics — the branch of physics concerned with the motion of bodies in a frame of reference
• nuclear physics, atomic physics, nucleonics — the branch of physics that studies the internal structure of atomic nuclei
• optics — the branch of physics that studies the physical properties of light
• particle physics, high-energy physics, high energy physics — the branch of physics that studies subatomic particles and their interactions
• plasma physics — the branch of physics concerned with matter in its plasma phase
• quantum physics — the branch of physics based on quantum theory
• rheology — the branch of physics that studies the deformation and flow of matter
• solid-state physics — the branch of physics that studies the properties of materials in the solid state: electrical conduction in crystals of semiconductors and metals; superconductivity; photoconductivity
• statistical mechanics — the branch of physics that makes theoretical predictions about the behavior of macroscopic systems on the basis of statistical laws governing its component particles
• thermodynamics — the branch of physics concerned with the conversion of different forms of energy

• natural science — the sciences involved in the study of the physical world and its phenomena

• wave theory, undulatory theory, wave theory of light — the theory that light is transmitted as waves
• corpuscular theory, corpuscular theory of light — the theory that light is transmitted as a stream of particles
• kinetic theory, kinetic theory of gases — a theory that gases consist of small particles in random movement
• relativity, theory of relativity, relativity theory, Einstein's theory of relativity — (physics) the theory that space and time are relative concepts rather than absolute concepts
• quantum theory — a physical theory that certain properties occur only in discrete amounts (quanta)