OCR GCSE Combined Science A key terms

The route of blood from the left side of the heart to the body tissues and back to the right side of the heart.

A straight line that has the same direction as a curve at a particular point. Its gradient gives the gradient of the curve at that point.

Setting a balance to zero, often with an empty container on it, so that the mass of the container is excluded from the next reading.

The people a communication is intended to reach, whose knowledge and needs influence how information should be presented.

An organ containing cells with the appropriate receptors to respond to a particular hormone.

A measure related to the average kinetic energy of the particles in a substance.

The difference between the final and initial temperatures: $\Delta\theta = \theta_{\text{final}} - \theta_{\text{initial}}$.

The ability of a material to resist breaking when stretched or pulled.

The pulling force in a stretched string or rope.

The constant velocity reached when the forces driving an object's motion balance the resistive forces, so its resultant force and acceleration are zero.

A hormone produced by the testes that stimulates sperm production and the development of male secondary sexual characteristics.

The mass of product calculated from a balanced equation, assuming the specified reactant reacts completely and all of that product is obtained.

Producing an early embryo with the same genes as a patient to obtain stem cells for that patient’s treatment.

The transfer of energy through a substance from a hotter region to a colder region, as particles pass energy to neighbouring particles.

A property of a material describing how readily it transfers energy by conduction. Higher thermal conductivity means faster energy transfer under the same conditions.

The breakdown of a compound into simpler substances when it is heated.

An energy store associated with the particles of an object or substance. Heating water increases its thermal energy store.

Energy transferred by heating, measured in joules (J). When a substance is heated without changing state, this transfer increases its internal energy and raises its temperature.

Producing an image using infrared radiation emitted by objects, allowing temperature differences to be detected.

A material or layer used to reduce the rate of energy transfer by heating.

A material with low thermal conductivity that reduces the rate of energy transfer by conduction.

Energy stored by an object because of the motion and arrangement of its particles.

The distance a vehicle travels between the driver recognising the need to brake and applying the brakes.

Chromatography carried out using a thin layer of silica gel or alumina coated onto a glass, metal or rigid plastic support.

Chromatography using a thin layer of silica or alumina on a supporting plate as the stationary phase, with a liquid solvent as the mobile phase.

Two forces from the same interaction, acting on different objects, equal in magnitude, opposite in direction and of the same type.

A hormone released by the thyroid gland that stimulates basal metabolic rate and helps control growth.