Key terms & definitions

The release of gases from volcanoes, which is thought to have helped form the Earth’s early atmosphere.

An area of volcanic activity fed by unusually hot mantle material rising beneath a plate, which can occur away from a plate boundary.

The release of gases from the Earth’s interior through volcanic activity.

An opening in the Earth’s crust through which lava, gases and other volcanic material erupt.

A feature of the Earth’s crust through which magma erupts onto the surface as lava, often building up a mountain from erupted material.

The Nazi ideal of a national community united by loyalty to the regime and defined by racial exclusion.

A Nazi militia formed in 1944 which conscripted males aged 16–60 who were not already serving in the armed forces to defend Germany.

The simultaneous firing of weapons by a group of soldiers.

The US law passed in October 1919 that defined the alcoholic drinks covered by prohibition and provided the mechanism for enforcing the Eighteenth Amendment.

The unit of potential difference, with symbol V; one volt is one joule per coulomb.

The unit of potential difference. One volt means one joule of energy is transferred per coulomb of charge: $1\text{ V} = 1\text{ J/C}$.

A turn in a poem’s thought or argument, often marked by a change of tone or a word such as ‘yet’ or ‘but’.

The potential difference between two points, which can drive an electric current through a circuit; measured in volts (V).

The common name for potential difference.

The potential difference between two points, measured in volts (V). It describes the energy transferred per unit charge passing between those points.

The potential difference between two points in a circuit, measured in volts (V). It describes the energy transferred per unit charge between those points.

A meter connected in parallel across a component to measure potential difference in volts.

A meter that measures potential difference between two points and is connected in parallel across the component being tested.

The amount of three-dimensional space occupied by an object, measured in cubed units such as cm³.

The amount of three-dimensional space occupied by a substance.

The amount of three-dimensional space occupied by a gas, measured in cubic metres (m³).

The space occupied by an object or sample, measured in cubic metres, m³, or smaller units such as cm³.

The amount of three-dimensional space occupied by a solid.

The amount of three-dimensional space occupied by an object, measured in cubed units such as $\text{cm}^3$.

The space occupied by an ingredient, commonly measured in millilitres (ml) or litres (l).

The number of offences in a specified place and period.

The multiplier that changes corresponding volumes or capacities from one similar solid to another.

A piece of apparatus used with a pipette filler to transfer a fixed, accurately measured volume of liquid.

Reliance on voluntary action by businesses, charities and communities rather than compulsory government measures.

An action that is consciously chosen, such as raising a hand.