What term refers to the variable that is manipulated or changed in an experiment?

The term that refers to the variable that is manipulated or changed in an experiment is the independent variable. This variable is intentionally altered by the researcher to observe its effect on other variables, specifically the dependent variable, which is measured or observed as a response to changes in the independent variable.

For example, if a scientist is testing how different amounts of sunlight affect plant growth, the amount of sunlight given to the plants is the independent variable, as it is what the researcher changes. In this context, other variables such as plant height or growth rate would be dependent variables, as they rely on the changes made to the independent variable.

Understanding the distinction between independent and dependent variables is crucial in designing experiments and interpreting results, as it allows for clear hypotheses and conclusions based on systematic changes.