Combined Science key terms

A solution of calcium hydroxide in water, used to test for carbon dioxide gas.

A resource with a finite supply that is not replenished as quickly as it is used.

A condition that restricts the rate of a process; improving that condition increases the rate until another condition becomes limiting.

A reactant that is completely used up in a reaction and therefore limits the maximum amount of product that can form.

The point beyond which a spring's extension is no longer directly proportional to the applied force.

A component whose current–potential difference graph is a straight line through the origin, showing constant resistance under the conditions tested.

A relationship represented by a straight line on a graph. A directly proportional relationship has a straight line passing through the origin.

The straight line along which a force acts.

A system developed by Carl Linnaeus that groups organisms into kingdom, phylum, class, order, family, genus and species.

An enzyme that breaks down lipids into glycerol and fatty acids.

Paper containing a coloured indicator that changes colour in acidic or alkaline conditions.

The brown-insulated wire that carries the alternating potential difference from the mains supply; its potential difference relative to earth is about 230 V.

A simplified explanation of enzyme action in which a substrate fits an enzyme's complementary active site, like a key fitting a lock.

A pair of outer-shell electrons that is not shared in a covalent bond.

A wave whose oscillations are parallel to the direction of energy transfer.

An energy source that produces relatively little greenhouse gas emission per unit of energy supplied, taking account of its production and use.

An ore containing a relatively low percentage of the metal or metal compound of interest.

A substance used to reduce friction between moving surfaces.

Applying a lubricant, such as oil, between moving surfaces to reduce friction and unwanted heating.

The internal space of a blood vessel through which blood flows.

A type of white blood cell that produces antibodies; some also produce antitoxins.

An enzyme found in tears that breaks down and kills bacteria on and around the eyes.

A region where a magnet or magnetic material experiences a force.

The direction of the force that would act on a north magnetic pole placed at a particular point.

A line used to represent a magnetic field. Its arrow shows the field direction, and the spacing between lines represents field strength.

A measure of magnetic field strength, represented by $B$ and measured in tesla (T).

An attractive or repulsive non-contact force between magnetic poles.