In any given experiment, there is a control variable, an independent variable, and a dependent variable.
The independent variable is the variable which can be continuously changed by the experimenter. This is necessary in order to come up with a dependent variable.
The dependent variable is the outcome variable which changes with whichever independent variable is being used/changed. This variable outcome is dependent on whatever the independent variable is.
A control variable also plays a role in every experiment. A control variable is any other variable within the experiment that could potentially affect the outcome.
Hope this was helpful.
