What is the significance of control variables in an experiment?

• A. They are irrelevant to the experimental outcome
• B. They are measurements taken after an experiment
• C. They help ensure that the experiment is fair and valid
• D. They represent the average of all trials conducted

Answer: (C)

Control variables are critical components of an experiment because they help ensure that it is conducted in a fair and valid manner. By controlling certain variables, researchers can isolate the effects of the independent variable on the dependent variable. This means that any changes observed in the outcome can be attributed directly to the independent variable, rather than to other factors that might influence the results.

For example, if an experiment is designed to test how different amounts of light affect plant growth, factors such as soil type, water amount, and plant species should be kept constant. These factors are the control variables. By maintaining these constants, the experiment can yield reliable and consistent data, allowing for a clear interpretation of how the independent variable (light amount) affects the dependent variable (plant growth).

This controlled approach increases the experiment's validity and enhances the credibility of its findings, making it easier for others to replicate the study and confirm the results.