control variables
What control variables means in Biology GCSE, as defined for AQA.
Definitions of control variables
Exam boards and our study guides word this term in slightly different ways. Learn the version your board uses.
Check what you remember
Read the wording for your board, then hide it and explain control variables in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: AQA
The volume and concentration of each substance, the bacterium, incubation temperature, and disc size, kept the same for a fair comparison.
Variables such as temperature, volumes and concentrations that should be kept constant in the investigation.
Temperature, carbon dioxide concentration, pondweed length and acclimatisation time are kept constant.
Variables such as temperature and pH that are controlled so rate comparisons are valid.
Topics that use control variables
- Culturing microorganisms (biology only) (AQA GCSE)
- Rate of photosynthesis (AQA GCSE)
- The human digestive system (AQA GCSE)
Related terms
- Absorption and transport
- active site
- Active site and substrate binding
- Agar gel plate
- Amylase
- Anabolic and catabolic reactions
- Analysis and interpretation of data
- Antibiotic clear zones
Using control variables in the exam
Check the command word and mark scheme for your exact question. After comparing your explanation with the reference, use the term in an answer on the linked topic. This practice does not predict an exam mark.
Practise Biology questions
Create a free account to answer exam-style questions on this topic and get feedback on your answers.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge