In chemistry, electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. An ionic compound, in this case salt, is dissolved with an appropriate solvent, such as water, so that its ions are available in the liquid. An electrical current is applied between a pair of inert electrodes immersed in the liquid. The negatively charged electrode is called the cathode, and the positively charged one the anode.
Electrolysis is the process by which an electric current is passed through a substance to affect a chemical change. The chemical change occurs when the substance loses electrons (oxidation) or gains them (reduction). In the two experiments listed below, the first reactive substance is water and the second one is a copper sulfate solution.