What do we call the setup in an experiment where the independent variable is not altered?

The setup in an experiment where the independent variable is not altered is referred to as a control. The purpose of a control is to provide a baseline for comparison with the experimental group, where the independent variable is manipulated. By keeping the control unchanged, researchers can better observe the effects of the independent variable on the dependent variable. This helps to establish whether any observed changes in the experiment are indeed a result of the manipulation of the independent variable, rather than other factors.

In this context, "variable" typically refers to any component of the experiment that can change or be changed, and "constant" refers to elements that are kept the same throughout both the control and experimental groups to ensure that the experiment is fair. "Factor" can be a more general term that encompasses various components of an experiment but does not specifically imply the stability of a setup like a control does. Therefore, identifying the control is crucial for framing a reliable scientific investigation.