Physics Words
- Optical Fibre A device that transmits light using the process of total internal reflection.
- Orbit The path an electron follows around the nucleus of an atom or the path a planet follows around the sun.
- Oscilloscope A device that can be used to display signals or waves on a screen, e.g. an Alternating Current (AC) electrical supply
- P wave A type of seismic wave that is longitudinal
- P waves A type of seismic wave that is longitudinal
- P.d. An abbreviation for "potential difference", also called voltage. It is defined as "work done per unit charge" and is measured in volts.
- Parallel An arrangement in an electric circuit where components are placed "in parallel" with each other so that the current has a "choice" of which component to go through
- Parallel circuit An arrangement in an electric circuit where components are placed "in parallel" with each other so that the current has a "choice" of which component to go through
- Particle A general name for a very small thing (e.g. an atom or molecule) that everything is made of
- Pay back time The time it takes something to pay for itself by saving you money
- Period The amount of time it takes for something (e.g. whole wave to pass by) to happen
- Permanent magnet A magnet that will permanently retain its magnetism, e.g. the classic red and blue bar magnets
- Planet A large body of mass that orbits a sun
- Plastic deformation When a spring is stretched and does not return to its orginal shape.
- Plug A British plug contains three wires - earth, live and neutral
- Plum pudding model An old model of atomic structure that stated that atoms were balls of positive charge with negative electrons dotted around inside them, like raisins in a plum pudding.
- Plutonium A fuel used in nuclear power stations
- Positive charge The electrical charge on a proton (+1).
- Potential difference P.d., also called voltage. It is defined as "work done per unit charge" and is measured in volts.
- Potential energy A type of stored energy that a device can have. Potential energy is usually elastic or gravitational potential energy.
- Power Defined as "the rate of doing work" and measured in Watts.
- Power station A building that generates electrical energy
- Proton One of the the sub atomic particles found in the nucleus. Protons have a positive charge.
- Protostar Early stage in star life cycle before the process of fusion begins.
- Radiation A term to describe either electromagnetic radiation (light, infra red etc) or ionising radiation (alpha, beta and gamma)
- Radiation (thermal) A form of heat transfer where heat is transmitted through infra red waves.
- Radiation dose The amount of radiation a person has absorbed.
- Radio waves Long wavelength electromagnetic waves that are used to carry signals.
- Radioactive A substance that is capable of emitting alpha, beta or gamma radiation is called "radioactive".
- Radioactive decay When a radioactive substance gives out a form of radioactivity (e.g. alpha, beta particles) in order to become more stable.
- Radioisotope An isotope that is radioactive, i.e. capable of emitting radiation.
- Reaction time The time it takes someone to react to a stimulus
- Real image An image that can be formed on a screen.
- Red giant Red giants are formed when a smaller main sequence star runs out of fuel, cools and expands.
- Red shift An apparent change in wavelength of light emitted by something that is moving away from us.
- Red supergiant Red supergiants are formed when a massive star runs out of fuel, cools and expands.
- Reflect When a wave bounces back from a surface
- Reflection The process of a wave bouncing back from a surface.
- Refraction When a wave slows down or speeds up due to travelling in a more or less dense medium.
- Renewable Supplies of a renewable substance will not run out for example biofuels
- Repel The action of pushing something away, for example, a north pole repels another north pole.
- Resistance A property of a device that "resists" the flow of electric current through it
- Resistor A device that resists an electric current going through it.
- Resultant force The total effect of all of the forces acting on an object, simplified to one force.
- Rutherford scattering experiment An experiment done in the early 20th Century that provided evidence for atoms being made of electrons orbiting a central, positive nucleus.
- S wave A type of seismic wave that is transverse.
- S waves A type of seismic wave that is transverse.
- Satellite An object that orbits another object, e.g. the moon orbiting the Earth.
- Scalar quantity A quantity that only consists of a size.
- Series An arrangement in an electric circuit where components are placed next to each other
- Series circuit A circuit where components are placed next to each other
- Solar A renewable energy source that involves turning sunlight into electrical energy
- Solar panels Devices that convert light energy into electrical energy.
- Solar system A part of space that contains one or more stars and the planets that orbit those stars.
- Solid One of the three states of matter, along with liquid and gas
- Source of energy Something that can be used to generate energy, e.g. burning wood
- South pole A part of a permanent magnet that will be attracted to the Earth's north pole
- South-seeking pole A magnetic pole that will point towards the south pole
- Specific latent heat of fusion The amount of energy needed to turn1kg of a substance from a solid into a liquid.
- Spectrum A range of frequencies; for example, the electromagnetic spectrum
- Specular reflection A type of reflection where waves are reflected back at the same angle.
- Speed Distance divided by time
- Speed of light 300,000,000m/s - the speed all electromagnetic waves travel at through a vacuum.
- Speed-time graph A graph that represents an object's speed over different periods of time.
- Star A body in space that uses nuclear fusion to emit radiation
- Static electricity When electrical charges "stand still", as opposed to "move around" (which is called an electric current)
- Step down A type of transformer that DECREASES voltage
- Step up A type of transformer that INCREASES voltage
- Stopping distance The distance a car travels in the time it takes the car to stop, including both the thinking distance and the braking distance.
- Sublimation When a solid changes directly into a gas without becoming a liquid first.
- Sulfur dioxide A gas released when coal is burned; it causes acid rain.
- Supernova An explosion of a massive star.
- Telescope A device used to see distant objects such as stars and planets.
- Terminal velocity The final speed a moving object will reach due to its inability to overcome resistive forces.
- Thermal energy Also called heat energy
- Thermal radiation Also called infra red radiation - a form of radiation that is given out by hot objects.
- Thermistor An electrical device whose reistance decreases when it gets hotter.
- Thinking distance The distance a driver covers while reacting to a danger.
- Tidal barrage A power station that uses tidal power. Usually built across an estuary.
- Total internal reflection A process when light is reflected inside a material by striking the boundary at an angle greater than the material's critical angle
- Tracer A general name for any radioisotope that is used to track the movement of a chemical.
- Transformer A device that can be used to increase voltage (step up transformer) or decrease voltage (step down transformer)
- Translucent An object that partally lets light through - you can see light coming through but can't see specific shapes.
- Transmit When a substance allows waves or radiation to pass through it.
- Transparent When an object allows enough light through it so that shapes and objects can be made out
- Transverse wave A wave where the displacement causing the wave is at right angles to the direction of the movement of energy of the wave
- Turbine A device in power stations that is turned by steam or water. It is connected to a generator.
- U value A measure of how effective insulation is in keeping heat energy in.
- Ultra violet radiation Electromagnetic radiation with a wavelength slightly shorter than violet light.
- Unit Also called a "kilowatt hour" - a unit of electricity
- Universe The whole of space, made of billions of galaxies each containing billions of stars
- Uranium An element and a fuel used in nuclear power stations
- V Short for Volts, the unit of potential difference
- Vacuum An area from which particles such as air has been removed.
- Vector quantity A quantity that has both size AND direction.
- Velocity Speed in a given direction.
- Velocity-time graph A graph that represents an object's velocity over different periods of time.
- Virtual image An image from which rays of reflected or refracted light appear to diverge.
- Visible light A section of the electromagnetic spectrum that we can see with the naked eye.
- Visual pollution A term used to describe something being ugly to look at.