Science Fair

For my science fair project I did an experiment about which one would make more electricity, lemons or potatoes. My hypothesis was I think the lemon would make more electricity because lemons have acids. I put copper and zinc in the lemons and potatoes to help conduct the electricity. I used a multi-meter to measure the voltages. I connected leads to the multi-meter and the other side connecting to the lemon or potatoes. The black lead is the negative terminal and so is the zinc. The red lead is the positive terminal and so is the copper.