What is an independent variable?

An independent variable is defined as a factor in an experiment that is intentionally manipulated to observe its effect on other variables, particularly the dependent variable. It is considered independent because its value does not change in response to other variables; instead, it is the variable that researchers change or control to assess its influence on the outcome of the experiment.

For example, if a scientist is investigating how different amounts of sunlight affect plant growth, the amount of sunlight is the independent variable because the researcher can vary it without being influenced by other factors in that specific experiment. This distinction allows researchers to establish cause-and-effect relationships.

The other options describe different types of variables that do not align with the definition of an independent variable. Constants, for example, should not change during the experiment, while controlled variables serve to limit the impact of external factors on the results. An understanding of these distinctions is crucial for effectively designing experiments and interpreting their results.