To illustrate the decomposition of water, connect the copper strips, H
H, to the poles of the battery by means of wires, as shown in Fig. 3,
and insert them in a tumbler of water acidulated with a few drops of
sulphuric acid. Instantly bubbles will rise from the copper strips,
showing that gas is being disengaged from the water. The strip
connected with the carbon plate will disengage oxygen, while the strip
connected with the zinc plate will disengage hydrogen.
[Illustration: FIG. 3.--DECOMPOSITION OF WATER.]