Constant and control are two mathematical concepts. A variable is a value that changes or can change. A control in science is an experiment that makes sure that only one variable is tested. A controlled variable is one which is allowed to change, but it is intentionally kept constant throughout the experiment.
The purpose is to show the relationship between dependent and independent variables. On the other hand, a continual variable does not change. Ideally, it is expected to remain the same throughout the experiment.
It would be necessary for a scientist to know both of these terms. Both controls and constants are variables that are used in experiments. During operation, a constant doesn't change. Examples of constants in experiments include when water freezes or boils, as well as the speed of light.
Control can vary but isn't kept constant to show the dependent and independent variables relationship. Being controlled allows the variables to be recorded and monitored to find their influence. Temperature, pressure, and time are examples of controls. It is common for an experiment to have more than one control.