AQA Science: Glossary - Fair Test
A fair test is one in which only the independent variable has been allowed to affect the dependent variable.
e.g. A fair test can usually be achieved by keeping all other variables constant.
e.g. Fran and Federico are investigating how the electrical resistance of wires changes with length. Unfortunately both of them let the current get too high for shorter wires, which dramatically increases their temperature. Since temperature affects resistance (in addition to the length), it is not a fair test.
- Identify the independent and dependent variables in their investigation.
- Explain why their experiment is not a fair test.
- What could they do to make it a fair test?