Because these are redox reactions, one metal is going to be oxidized and the other reduced. The metal which is oxidized will be giving up electrons. If electrons enter the "negative" terminal of a voltmeter the sign on the voltage reading will be positive (+). Since the CBLs were only able to detect positive voltages in the configuration we used, each metal in a pair which had the potential to be oxidized compared to the other metal in the pair would be attached to the negative or BLACK lead from the CBL. This metal is the stronger reducing agent in the pair.

So it is possible to rank the metals from most easily to least easily oxidized (or least easily to most easily reduced).

This, of course, mimics the activity series. If the list were extended by similar experiments, however, we would notice some interesting differences. The activity series was originally designed to indicate what would happen when substances were mixed. What we are beginning to compile based on the data from this experiment indicates what might potentially happen.