Edexcel GCSE Physics key terms

A temperature scale on which the freezing point of water is approximately 0 °C and the boiling point is approximately 100 °C at standard atmospheric pressure.

The resultant force on an object moving in a circle, directed towards the centre of that circle.

A continuing process in which neutrons released by nuclear fission cause further nuclei to undergo fission.

The difference between the final and initial gravitational potential energy, measured in joules (J).

Momentum gained or lost, calculated as final momentum minus initial momentum.

The difference between the final and initial temperatures: $\Delta\theta=\theta_{\text{final}}-\theta_{\text{initial}}$.

The energy transferred to or from a substance as its temperature changes, measured in joules (J).

The difference between an object's final and initial vertical heights, measured in metres (m).

A physical transition between solid, liquid and gas, such as melting or boiling.

The quantity of electric charge transferred, measured in coulombs (C).

The transfer of electrons between materials when their surfaces are rubbed together.

The energy stored in a battery's chemicals that decreases as the battery powers a device.

A safety device that automatically opens a switch when the current becomes dangerously large.

A drawing that uses standard symbols and lines to show how electrical components are connected.

A conducting path with no break, allowing charge to flow.

A system across whose boundary no energy enters or leaves.

The fluid-filled structure in the inner ear where vibrations are converted into nerve signals.

Detection of two gamma-ray photons from the same annihilation event at almost the same time.

An event in which objects interact for a short time and exert forces on one another, usually changing their velocities.

The number of collisions occurring in a given time.

A material that transmits selected wavelengths of visible light and absorbs others.

A small, icy body that orbits the Sun and can develop a cloud of gas and dust, and a tail, as it approaches the Sun.

A small magnet that can turn freely to align with the magnetic field around it.

A force in one chosen direction, usually horizontal or vertical, which forms part of a resolved force.

The property of a substance that allows its volume to decrease when pressure is applied.

A decrease in the volume occupied by a gas.

The physical change from a gas to a liquid.