Which part of a scientific experiment is manipulated by the experimenter?

In a scientific experiment, the independent variable is the factor that the experimenter manipulates or changes to observe its effects on other variables. This manipulation allows researchers to establish cause-and-effect relationships. By altering the independent variable, scientists can assess how it influences the dependent variable, which is the outcome that they measure.

For instance, if a researcher is studying the effect of different temperatures on plant growth, the temperature would be the independent variable because it is what the experimenter changes. The growth of the plants, which is measured as a result of the temperature changes, would be the dependent variable. Control variables, on the other hand, are the conditions that are kept constant to ensure a fair test. This distinction helps clarify how the independent variable plays a crucial role in scientific investigations.