Separating water into H2 and O2

 Here we connected two pieces of copper wire to a 9-volt battery.  We filled two test tubes and a beaker with distilled water.  We added baking soda to the water because we needed the ions to transfer the H+ and the OH-.  Hydrogen gas formed readily but the oxygen gas was inhibited by the copper oxidizing at the anode. We are going to try this experiment again with different electrodes.