For example, a scientist wants to see if the brightness of light has any effect on a moth being attracted to the light. The brightness of the light is controlled by the scientist. This would be the independent variable. How the moth reacts to the different light levels (distance to light source) would be the dependent variable.
Independent vs Dependent Variable Key Takeaways
The independent and dependent variables are the two key variables in a science experiment.
The independent variable is the one the experimenter controls. The dependent variable is the variable that changes in response to the independent variable.
The two variables may be related by cause and effect. If the independent variable changes, then the dependent variable is affected.