OCR GCSE Combined Science A key terms

A material through which electric current can flow, such as a metal wire.

The protection and management of species and habitats to maintain biodiversity.

The principle that energy cannot be created or destroyed, only transferred between stores.

The principle that mass is not created or destroyed during a chemical reaction: the total mass of reactants equals the total mass of products.

The principle that the total momentum of a system stays constant when no resultant external force acts on it.

Motion with unchanging speed and direction.

A condition in which the space occupied by a gas does not change.

An organism that obtains food by feeding on other organisms.

A force acting between objects that are physically touching.

Unwanted material mixed with a material being collected or processed.

A numerical variable that can take any value within a range, such as time or temperature.

Variation in which a characteristic can take a range of values, with many intermediate values.

The use of methods to prevent pregnancy.

A factor kept constant so that it does not provide an alternative explanation for the results.

Energy transfer by the movement of a liquid or gas.

The direction in which positive charge would flow: from the positive terminal to the negative terminal through an external circuit.

The number used to multiply or divide a value when changing between units, found from the relationship between those units.

Two values that locate a point on a graph, written as $(x, y)$: the horizontal-axis value first, then the vertical-axis value.

The organisation of the activities of different body parts so that they work together to produce an appropriate response.

A part of the body that receives and processes information from receptors and coordinates a response.

A blood vessel that supplies the heart muscle with blood.

A blood vessel used to create a new route for blood around a narrowed or blocked coronary artery.

Disease in which fatty deposits narrow the coronary arteries, reducing the blood supply to the heart muscle.

The structure formed from the follicle after ovulation, which produces progesterone.

A relationship in which two variables change together; this alone does not establish that one causes the other.

The SI unit of electric charge. One coulomb passes a point when a current of one ampere flows for one second.

A strong bond formed when atoms share a pair of electrons.