What Is a Variable in a Science Project?

Understanding the different types of variables is critical when designing a scientific experiment. It is important to plan an experiment with a single independent variable with appropriate controls so that the results obtained are reliable and can be interpreted correctly.

What Is a Variable?

• A variable is a quantity that can change during the course of an experiment. Temperature, amount of sunlight, and time are all examples of variables.

Independent and Dependent Variables

• The independent variable is the quantity that is changed by the scientist, and the dependent variable is measured in response to the independent variable. For example, if an experiment is measuring the amount of plant growth in response to different temperatures, the temperature would be the independent variable, and the plant growth would be the dependent variable.

Controls

• A control variable is any quantity that is kept constant during an experiment. For example, in the example above, factors such as sunlight and water should be control variables and remain constant so that the dependent variable relies only on the independent variable.

Significance

• Having only one independent variable means that any change in the dependent variable is due to a response to the independent variable and no other factors.

Considerations

• In many experiments, there will be different trials to test the same set of dependent and independent variables. When the results are consistent between different trials, the results are considered to be more reliable.