what is the control variable in an experiment

A control variable is a variable or element that is held constant or limited in an experiment or research study. It is not of primary concern in the experiment, but it is important because it can affect the experiments result. Control variables are used to ensure that the results are solely caused by the experimental manipulation of the independent variable on the dependent variable. In an experiment, the researcher holds the controlled variable constant or controls it. It is also known as a constant or control variable. The controlled variable is not part of an experiment, and it is not an independent or dependent variable. However, it is important to identify and control the variables that could change the outcome of an experiment in a way that makes it invalid. Control variables must be kept constant to prevent them from influencing the effect of the independent variable on the dependent variable.