What does it mean to hold a variable constant in an experiment?

Holding a variable constant in an experiment means preventing it from varying among experimental conditions. This is crucial in experimental design because it helps isolate the effects of the independent variable on the dependent variable. By keeping certain variables constant, researchers can ensure that any observed changes in the dependent variable are likely due to the manipulation of the independent variable, rather than other external factors.

For instance, if a study is examining the impact of different amounts of sunlight on plant growth, the type of soil used can be held constant across different treatment groups. This ensures that differences in plant growth can be attributed specifically to the amount of sunlight, rather than variations in soil quality.

This approach enhances the internal validity of the experiment and allows for a clearer interpretation of the results. It underscores the importance of controlled conditions in research, facilitating meaningful comparisons within the controlled framework of the experiment.