 |
AQA Science: Glossary - Control Variables
|
A control variable is one which may, in addition to the independent variable, affect the outcome of the investigation. This means that you should keep these variables constant; otherwise it may not be a fair test. If it is impossible to keep it constant, you should at least monitor it; in this way you will be able to see if it changes and you may be able to decide whether it has affected the outcome of the experiment.
e.g. Valerie and Vernon's experiment with the cylinder of putty's electrical resistance would have been a fair test if they had controlled the cross-sectional area. By cutting part of the putty off, they would have been able to investigate different lengths, with no effect from other variables.
| 