What type of variable is manipulated in an experiment?

In an experiment, the manipulated variable is known as the independent variable. This type of variable is intentionally changed or controlled by the researcher to observe its effect on another variable, which is typically the dependent variable. By manipulating the independent variable, researchers can establish causal relationships and determine how changes in this variable influence outcomes.

For example, if a scientist is studying the impact of different amounts of sunlight on plant growth, the amount of sunlight is the independent variable, as it is what the scientist adjusts. The growth of the plants, measured in height or biomass, would be the dependent variable, as it depends on the amount of sunlight received.

This distinction is essential for experimental design, allowing scientists to isolate and identify the effects of specific changes. In contrast, the other types of variables serve different purposes: the dependent variable is measured as a response to the change, control variables are kept constant to provide a fair test, and the term "experimental variable" is less commonly used and can sometimes refer to the independent variable, which might cause confusion in terminology.