Combined Science key terms

Producing an embryo with the same genes as a patient so that its stem cells can be used for treatment without being rejected by the patient’s body.

The transfer of energy from a hotter region to a cooler region through a material, without the material flowing as a whole.

The ability of a material to transfer energy through itself by heating.

A chemical reaction in which a substance breaks down into simpler substances when heated.

The increase or decrease in a material’s thermal energy store as its temperature changes, measured in joules.

Energy associated with the particles within a substance. Heating a substance usually increases this store.

An increase in the volume of a substance as its temperature rises.

Producing an image from infrared radiation emitted by objects, revealing differences in their temperature.

Using insulating materials to reduce the rate of energy transfer by heating.

An electrical component whose resistance changes with temperature. For the thermistors studied here, resistance decreases as temperature increases.

A device that controls heating or cooling to maintain a chosen temperature.

The distance a vehicle travels during the driver's reaction time, before the brakes are applied.

Two equal and opposite forces of the same type, exerted by two interacting objects on each other. Each force acts on a different object.

A cable containing three separately insulated conducting wires: live, neutral and earth.

A hormone released by the thyroid gland that stimulates basal metabolic rate and supports growth and development.

A group of cells with a similar structure and function.

Damage to a group of living cells, which can impair how a tissue works.

A method of finding the volume of one solution needed to react completely with a measured volume of another solution.

The volume of solution delivered from a burette during a titration, calculated as final reading minus initial reading.

Tobacco mosaic virus: a plant pathogen that causes a mosaic pattern of leaf discolouration, reducing photosynthesis and growth.

All the energy supplied to a device or system, including the energy that is subsequently transferred usefully and the energy that is wasted.

The complete reflection of light back into a material at its boundary, under suitable conditions. It keeps light travelling along an optical fibre.

Describes a poisonous substance that can cause serious harm or death.

The extent to which a substance causes harm to cells, tissues or an organism.

A poison produced by a pathogen that can damage host cells or tissues.

A line across a habitat along which organisms are recorded, directly or using quadrats, to investigate changes in distribution.

A device that changes the potential difference of an alternating electrical supply.