Then it hit me. If "potential difference" is by and large determined by the number of free electrons in each different metal then perhaps a potential difference could be created between two pieces of the same metal. How? By making sure that one of the pieces had substantially more free electrons than the other. The only way I could figure how to easily do that was by adjusting the size ratio between the two electrodes.
For example; if you start with a piece of metal 1" square and 1/8" thick and, for the purposes of the example, we know that such a piece of that metal would have a billion free electrons. Then we could assume that a piece of the same metal which was twice as large (surface area, maintaining the 1/8" thickness) would have double the amount of free electrons (2 billion), right? And therefore the larger piece should have a greater potential to be able to give up electrons than the smaller piece, as well as having greater conductivity (due to size).
Armed with that theory I decided to devise a couple of simple
experiments to test it's validity. The experiments:
1) I had actually done this experiment previously but the data I obtained
from it is useful to mention at this point. What it involves is using two
electrodes made of aluminum foil in a solution of NaOH/KOH and water. Most
people who paid some small bit of attention in High School chemistry know
that the above solution will react vigorously with aluminum to release
H2. I wanted to see how using two aluminum electrodes, connected to each
other by a wire, would affect the process.
For the experiment I used a clean, wide mouth Mason jar (1-qt)
and filled it 2/3 full of warm tap water (distilled would be better). Then
I added enough NaOH/KOH solution to bring the level of the liquid to within
1 1/2" of the top of the jar.
Next I took two pieces of aluminum foil, 6" square, and folded them over several times until I ended up with two electrodes about 1" wide and 6" long. I did this to give them a bit of rigidity so that I could keep them in position in the cell while the reaction was taking place.
Next I slid the aluminum electrodes down into the jar, on opposite sides. The longer sides being vertical, and secured them in place with alligator clips. Then I connected my multimeter to the electrodes and turned it on. I observed a potential difference between these two identical electrodes of .57 volts. I verified this potential difference by reversing the multimeter leads and the result was a negative reading on the dial. It was still climbing when I hooked a wire between the electrodes to form a complete circuit between them.
After several minutes it appeared that the the electrode which was serving as the cathode (as indicated by current direction) was decomposing at a much slower rate than the electrode which was serving as cathode. To further test this I hooked my power source to the cell and accelerated the process. The cathode piece was indeed decomposing at a much slower rate than the anode.