My kids and I did this last year for a science project, sliced up an orange or grapefruit, stuck a copper wire on one side, and a dissimilar metal (steel, zinc, etc) on the other. Then we wired them in series and lit a 3volt LED. Each "cell" produced about 1/2 a volt.gspig said:
I would imagine if you stuck copper & zinc rods in the earth and watered them with a strong acid, you'd get some voltage, but not enough to do anything practical. The cost of the copper & zinc, and the frequency of replacement of the rods makes it pretty impractical & expensive.
Bill
