OCR GCSE Combined Science B key terms

The change of water vapour into liquid water.

Apparatus that cools vapour so that it changes into a liquid.

Another variable that could explain an apparent relationship between the two variables being studied.

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 atoms are neither created nor destroyed in a chemical reaction, so the total mass is conserved.

The principle that the total momentum of a system stays constant when the resultant external force is zero.

An organism that obtains food by feeding on other organisms.

A force between objects that are physically touching.

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

The use of a method to prevent pregnancy.

A comparison treatment used to help establish whether the factor being investigated caused an observed difference.

A variable kept constant so that its effect does not interfere with the relationship being investigated.

The direction of current defined as the direction in which positive charge would flow; in a metal, it is opposite to electron movement.

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

An artery that supplies the heart muscle with blood containing oxygen and nutrients.

An operation that creates an alternative route for blood around a blocked coronary artery.

Disease in which the coronary arteries become narrowed or blocked, reducing the blood supply to heart muscle.

The structure formed from the follicle left behind in an ovary after ovulation; it produces progesterone.

A relationship in which two measured quantities tend to change together. It does not, on its own, establish that one causes the other.

A strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

The breakdown of larger hydrocarbon molecules into smaller, more useful molecules using high temperatures, often with a catalyst.

Growing different crops in the same field in successive years.

A covalent connection between polymer chains that restricts their movement relative to one another.

The area of a flat section through an object; for a circular section, $A = \pi r^2$.

A naturally occurring mixture of many hydrocarbons, extracted from rocks in the Earth's crust.

A substance in which aluminium oxide is dissolved during aluminium extraction, allowing electrolysis at a lower temperature than melting pure aluminium oxide.