Edexcel GCSE Physics key terms

Not moving; on a distance–time graph this is represented by a horizontal line with zero gradient.

A historical model in which the Universe expands but maintains the same overall appearance and average density over time.

A device that decreases an alternating potential difference.

A transformer that increases the alternating potential difference across its output coil.

Removal or destruction of microorganisms so that equipment is safe to use.

A detectable event or change, such as a hazard appearing, that can cause a response.

The total distance travelled from detecting a hazard until the vehicle has come to rest.

The duration over which an object's velocity changes from its initial value to its final value.

The amount of energy held in a particular energy store, such as a chemical, kinetic or thermal energy store.

A change of shape in which an object becomes longer because forces pull different parts apart.

A particle smaller than an atom, such as a proton, neutron or electron.

The physical change in which a solid changes directly into a gas without first becoming a liquid.

A unit smaller than the unprefixed unit, formed using a multiplier less than one, such as a millimetre.

Equipment is suitable for a measurement if it can give a useful reading for the wave being investigated, with limitations that can be identified and evaluated.

A powerful explosion produced when a massive star's core collapses, throwing its outer layers into space.

A component that opens or closes a circuit so that current is stopped or allowed to flow.

An object or group of objects chosen for study, with a boundary separating it from its surroundings.

The dividing line between a system and its surroundings; it determines what is included in the energy account.

A straight line drawn at a point on a curve so that it has the same local gradient as the curve there.

The velocity of an object at an instant, directed along the tangent to its circular path.

To set a balance to zero with an empty container on it, so it measures only what is added.

An instrument that collects electromagnetic radiation from a distant object so it can be detected or imaged.

A measure related to the average kinetic energy of the particles in a substance.

A material that becomes magnetised readily but loses most of its magnetism when the magnetising field is removed.

A pulling force transmitted by a taut string, rope or cable, acting along it.

A measure of how readily thermal energy is transferred through a material by conduction. A material with a lower thermal conductivity is a better thermal insulator.

The energy associated with the random motion and arrangement of particles in a substance.