Physics key terms

Energy an object gains when it is raised in a gravitational field.

The energy stored because of an object's position in a gravitational field; near Earth's surface it increases as the object is raised.

The energy store associated with an object's position in a gravitational field; it increases as the object is raised.

The attractive force between objects with mass; it pulls the material in a nebula inwards.

The warming caused when gases in the atmosphere absorb infrared radiation emitted by the Earth and re-emit it in different directions, including back towards the surface.

A gas that reduces the rate at which thermal energy escapes from Earth to space; carbon dioxide is an example.

The ability of tyres to exert frictional forces on the road without sliding.

The time taken for the number of undecayed nuclei in a sample to halve, or for its activity or count rate to fall to half its initial level.

Something with the potential to cause harm.

The interval between the lowest and highest sound frequencies that a person can detect.

The transfer of energy to a system because of a temperature difference.

A graph showing how the temperature of a substance changes as it is heated, commonly plotted against time.

The transfer of energy to a component’s thermal energy store when an electric current passes through it.

The transfer of electrical energy to thermal energy when charge flows through a component with electrical resistance.

A component that becomes hot when an electric current transfers energy to it.

A model in which Earth and the other planets orbit the Sun.

The unit of frequency; one hertz means one complete oscillation per second.

The unit of frequency; one hertz means one complete cycle or oscillation per second.

The relationship in which the extension or compression of an elastic object is directly proportional to the applied force, provided the limit of proportionality is not exceeded.

A system that uses pressure transmitted through a liquid to transfer a force from one place to another.

Electricity generated when moving water drives a turbine, commonly using water released from behind a dam.

A stable condition in which the inward effect of gravity is balanced by the outward pressure of hot stellar material.

A proposed, testable explanation for an observation or pattern in evidence.

A transformer model in which all the input power is transferred to the output, so its efficiency is 100%.

The provision of visible light so that objects and surroundings can be seen.

Surrounded by a fluid, either completely or with only part of the object below a liquid's surface.

Radiation that reaches and falls on a surface.