Potato Battery

Casia did a unit on electricity back in 4th grade, where the kids connected wires to a battery to make a light go on. So when I was looking for an experiment that would compliment our unit on electricity, I was looking for something a little different. What I found was this great video on making batteries from various household items. Here are pictures from Casia's Potato Battery Experiment:

Casia used a copper penny as the cathode and a
galvanized nail as the anode. 

The big expense in this lab was the voltmeter
which I bought at Home Depot for about $40.

Casia playing around with the voltmeter.

Casia testing the voltage of the batteries in series.

Casia explaining to Garrett the difference between
batteries in series and in parallel.

This lab was mostly easy to execute, but we learned a few things along the way. Even after cleaning the penny, we couldn't get nearly the voltage that we could when we used a piece of copper wire instead. It was even more effective when it was curled around and stuck in the potato to increase the surface area contact. We were never able to get enough voltage or amps to light the LED light bulb that we removed from the flashlight. However, with the voltmeter, it was easy to demonstrate the difference between batteries in parallel and batteries in series and how it affects voltage and amps. 

Casia went on to experiment on a couple of lemons I had as well, but we ran out of time to complete all the experiments on the website above. Up next, creating a simple generator...