Control variables
What Control variables means in Combined Science GCSE, as defined for AQA.
Definitions of Control variables
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Reference: AQA
Key variables such as temperature, carbon dioxide concentration and the distance of the light source, kept constant to make the test valid.
Include starting temperature, volume of water, distance from heater or detector, and time interval, held the same to make the test fair.
Factors such as the volume of water sample used and the time or temperature of heating, kept the same to make comparisons fair.
Tissue type, size, temperature and time are kept the same for every piece to make the test fair.
Include temperature, carbon dioxide concentration and the pondweed itself.
Variables kept constant to make comparisons valid.
Topics that use Control variables
- Energy transfer during exothermic and endothermic reactions (AQA GCSE)
- Osmosis (AQA GCSE)
- Potable water (AQA GCSE)
- Properties of electromagnetic waves 1 (AQA GCSE)
- Rate of photosynthesis (AQA GCSE)
Related terms
- Absorption
- Aquifers
- Cell turgor and plasmolysis
- Change in mass
- Chlorine
- Choosing scales
- Combustion
- Concentration gradient
Using Control variables in the exam
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