In school, Jarrett learned that salt lowers the freezing point of water. He wants to test this in a home experiment. He adds an equal amount of salt and room-temperature water into three identical containers. What is a control of his experiment?
There is no control in this experiment.........
One or two of the containers should NOT have contained salt. Given a salt solution and a solution of pure solvent, a differential freezing point may have been observed.
Of course, to make the solutions in the beakers freeze, he would need an ice-salt or ice-ethanol bath, in which to immerse his containers.