Why is testing only one variable important in an experiment?

Testing only one variable is crucial in an experiment because it simplifies the experiment, making it easier to determine the specific effects of that variable on the outcome being measured. When only a single variable is manipulated, researchers can clearly identify how changes to that variable directly influence the results. This clarity is essential when drawing conclusions from the data collected.

If multiple variables were tested simultaneously, it would become much more challenging to understand which factor was responsible for any observed changes. This complexity could lead to ambiguous results that could be misinterpreted, making it difficult to reproduce the experiment or to apply its findings to real-world situations. Simplification allows for a more controlled study, ensuring that the investigation remains focused and the results remain valid.