| Change in the velocity of an object | Acceleration |
| Study of sound | Acoustics |
| Branch of dynamics dealing with the forces exerted by air or other gases on objects in motion | Aerodynamics |
| Branch of aeromechanics dealing with the forces exerted by air or other gases in motion | Aeronautics |
| Matter made of antiparticles, whose absence in the universe is explained by the grand unified theory | Antimatter |
| Colloquial term for a particle accelerator, a machine that increases the speed and energy of atomic particles and sends them in a steady stream at a target | Atom smasher |
| Tendency of the surface of a liquid to rise or fall when in contact with very small diameter tubes | Capillarity |
| Imaginary, reversible heat engine that operates at maximum efficiency | Carnot engine |
| Self-sustaining series of chemical or nuclear reactions | Chain reaction |
| Chamber in which a gas is cooled to a temperature slightly below its usual condensation point | Cloud chamber |
| Attraction between molecules of the same kind | Cohesion |
| Law stating that the angular momentum of an object is unchanged unless a net external torque acts on it | Conservation of Angular Momentum |
| Pair of forces that act in opposite directions but not on the same point on the same object | Couple |
| Amount of fissionable material needed to sustain a chain reaction in nuclear fission | Critical mass |
| Highest temperature at which a gas can be liquefied by pressure alone | Critical temperature |
| Speed that a rocket must achieve to escape the gravitational pull of the planet and fly off into infinity | Critical velocity |
| Unit used for measuring the intensity of radioactivity | Curie |
| Device developed by O.E. Lawrence that accelerates charged atomic particles | Cyclotron |
| Theory of magnetism which states that atoms are grouped in microscopic magnetic regions, which when aligned, produce a magnetic field | Domain Theory |
| Actual mechanical advantage divided by theoretical mechanical advantage | Efficiency |
| 2-word term describing the energy change that occurs when an atom gains an electron | Electron affinity |
| Type of nuclear reaction that occurs when a nucleus of uranium or other heavy element is split into two nearly equal parts, especially when bombarded by a neutron | Fission |
| Distance along the principal axis of a mirror from the focal point to the mirror | Focal length |
| Any push or pull that causes a body to move | Force |
| Force that slows down a moving object when it comes in contact with another surface | Friction |
| Process by which light nuclei are joined together—this type of nuclear reaction produces the sun’s energy | Fusion |
| Apparatus which detects radiation by permitting a gas to ionize when charged particles enter the instrument | Geiger-Mueller tube |
| Force of attraction that pulls objects toward each other | Gravity |
| Full name for GUT, the acronym for the theory stating that the 4 fundamental forces in the universe are actually part of a single process | Grand unified theory |
| Standard unit of frequency, abbreviated Hz | Hertz |
| Measure of apparent resistance to current flow in an alternating-current circuit | Impedance |
| Tendency of all objects to keep moving in the same path or to stay still if not moving | Inertia |
| nvisible radiation in the electromagnetic spectrum consisting of rays longer than those of the red end of the visible spectrum and shorter than radio waves | Infrared radiation |
| Form of radiant energy with frequencies lower than visible light but higher than radio waves | Infrared waves |
| Disturbance that results when 2 waves meet at a single point in space | Interference |
| Electrically charged atom | Ion |
| Piece of curved glass that focuses light rays passing through it to make an image | Lens |
| Instrument used to detect electrostatic charges | Leyden jar |
| Form of energy that can pass through space in a vacuum | Light |
| Object with properties of attracting certain substances, especially iron or steel | Magnet |
| Study of the behavior of objects and systems in response to various forces | Mechanics |
| Science and technology of separating metals from their ores and of compounding alloys | Metallurgy |
| Light waves longer than infrared waves and shorter than radio waves | Microwaves |
| Experiment in which the charge of a single electron was determined | Millikan’s Oil Drop Experiment |
| Elusive subatomic particle with no electric charge more fully defined in 1998 when physicists were able to determine that it has mass, or weight | Neutrino |
| Process of splitting an atomic nucleus into 2 parts to produce energy (the principle of the atomic bomb) | Nuclear fission |
| Process of combining 2 atomic nuclei to produce energy (the principle of the hydrogen bomb) | Nuclear fusion |
| Study of the structure and properties of the atomic nucleus | Nuclear physics |
| Study of light | Optics |
| Study of matter and energy and the way they interact | Physics |
| Transformation of mechanical energy into electric energy when certain crystals are subjected to a mechanical stress and the opposite surfaces become electrically charged | Piezoelectric effect |
| Highly ionized gas that is electrically neutral | Plasma |
| Study of highly ionized gases | Plasma physics |
| Wedge-shaped glass that breaks white light into the colors of the spectrum | Prism |
| Discrete bundles in which radiation and other forms of energy occur—it is the plural of quantum | Quanta |
| Branch of physics that deals with the behavior of matter at the level of the atom, the nucleus, and the elementary particle | Quantum mechanics |
| Energy sent out in the form of particles or waves, especially electromagnetic waves | Radiation |
| Release of radiation in the form of alpha and beta particles and gamma rays when their unstable nuclei decay | Radioactivity |
| Condition of turning back a ray of light when it strikes a surface | Reflection |
| Principle involved when an object standing in water looks broken at the water line because light travels slower in water than in air | Refraction |
| Atom whose mass is found in its nucleus, with electrons revolving about the nucleus just as planets revolve about the sun | Rutherford atom |
| Series of colors formed when a beam of white light is broken up passing through a prism | Spectrum |
| Distance travelled per unit time without reference to direction | Speed |
| Theory proposing that the universe has always been in appreciably the same state it is now, and that even though matter is continually being lost or dispersed, other matter is created to take its place | Steady-state theory |
| 2-word term for the maximum stress that a material can withstand before it breaks | Tensile strength |
| Stress on a material caused by the action of a pulling force | Tension |
| Study of the effects of energy changes including heat and work on physical and chemical systems | Thermodynamics |
| Scattering and polarization of a light beam passing through a system of particles, such as a solution of colloidal particles | Tyndall effect |
| Electromagnetic radiation with wavelengths that are shorter than those of visible violet light | Ultraviolet radiation |
| Completely empty space or void | Vacuum |