Summary
Highlights
Most science experiments involve three types of variables: independent, dependent, and control variables.
The independent variable, also called the manipulated variable, is what you change or manipulate in an experiment. It can stand alone and is typically found on the x-axis of a graph.
The dependent variable, or responding variable, depends on the independent variable. It's the variable you measure in the experiment and is found on the y-axis.
Control variables are factors that must remain constant to ensure accurate and reliable results in an experiment.
An example is used to illustrate these variables: determining if higher tire pressure increases gas mileage.
In the tire pressure example, the different air pressure (20 psi vs. 35 psi) is the independent variable, the measured miles per gallon is the dependent variable, and driving the same car each time is a control variable.
To summarize, the independent variable is what is changed, the dependent variable is what is measured, and control variables are kept constant to maintain accuracy.