Washington Comprehensive Assessment of Science (WCAS) Practice Test

In an experiment, control variables are the factors that are kept constant to ensure that any changes observed in the dependent variable are solely due to the manipulation of the independent variable. For example, if you are testing the effect of different types of fertilizer on plant growth, control variables might include the amount of water each plant receives, the type of plant used, the amount of sunlight, and the soil type.

Keeping these variables stable is crucial because it eliminates potential confounding factors that could influence the results. If the control variables were to change, it would be difficult to attribute any observed effect directly to the independent variable, leading to ambiguous conclusions about the relationship being studied. Thus, understanding and identifying control variables is essential for the integrity and reliability of experimental results.