OCR GCSE Combined Science A key terms

Motion at constant speed, so equal distances are travelled in equal time intervals.

Velocity that stays constant: the object moves at a constant speed in a straight line.

A standard amount used to express a measurement, such as a metre for length or a second for time.

Expressing the same quantity in a different unit, changing its numerical value but not the quantity itself.

A mixture of dyes that changes colour across a range of pH values, allowing an approximate pH to be found using a colour chart.

An atomic nucleus that can undergo radioactive decay, emitting particles or electromagnetic radiation.

An energy transfer that does not contribute to the intended purpose of a device or process.

A waste substance produced in the body that must be transported away and excreted.

Energy transferred in a way that fulfils the intended purpose of a device or process.

An energy transfer that contributes to the intended purpose of a device or process.

The energy transferred by a device or system in the way needed for its intended purpose.

Giving a vaccine to stimulate an immune response and memory cells, preparing the body to respond rapidly to a particular pathogen.

A preparation containing harmless forms of a pathogen, or its antigens, that stimulates an immune response and provides protection against a particular disease.

A region containing no matter.

How well an investigation tests the intended relationship, rather than the effects of uncontrolled variables.

A resistor whose resistance can be adjusted to change the current in a circuit.

Differences in characteristics between individuals.

A leaf with differently coloured areas, such as green areas containing chlorophyll and white areas lacking chlorophyll.

An organism that carries a pathogen between hosts.

A blood vessel that carries blood towards the heart.

The speed of an object in a specified direction, measured in metres per second (m/s).

A lower chamber of the heart that pumps blood out into an artery.

The ability of a process to work successfully in practice, producing a suitable product at an acceptable cost.

Workable in practice: technically possible, affordable and able to produce something useful.

Repeated movement backwards and forwards about a rest position.

A measure of a fluid’s resistance to flowing; a more viscous liquid flows less freely.

The range of electromagnetic waves that the human eye can detect.