I made a battery late last night from a plastic 16-oz cola bottle. I stuck a copper wire in one side, and a strip of aluminum foil in the other. Fizz, fizz, ahh. Put the cap on. I get 0.5v and enough current to pop an old television speaker softly. If the battery were designed/built better, you would get much more. So if anyone knows how to make decent batteries, I'd like to know. Might come in handy someday, so I want to get a good working model going. In addition, I noticed that when I applied DC current to the urine, through the aluminum foil and copper wire, a gas was released. The copper wire also got very tarnished in the process. Does anyone know what this gas might be? Or what it's good for? Wouldn't it be a killer if there's lots of good disgusting stuff in urine that we could have used all along for light/power etc.? Who knows!
Offered by Joe.
You were electrolyzing the water into hydrogen and oxygen. The oxygen was tarnishing the copper. The reason your urine battery works is the same reason lemon batteries work. They are both acidic, i.e. ureic acid or citric acid.
Offered by Jeremiah.