Build A Coin Battery With Basic Science
Looking for something to tinker with? Here ya go. With only copper coins, vinegar, foil and cardboard you can build your own battery. And according to the original uploader it's strong enough to power an LED and TV remote!
Grab a few pennies from around the house and clean them off by soaking them in vinegar. Add some salt and let them sit until they're shiny. Dry them off and place one of them on a sheet of cardboard. Trace around it so you have 9 circles total. Cut each circle out and soak those in a bowl of vinegar also (no salt). Next, grab a sheet of foil and fold it up into a small square, just big enough to fit the coin on. Trace around the coin and cut it out...do this until there are at least 9 foil circles.
To put the batter together put the coin down, and lay a soaked cardboard disk on top with a foil disk on top of that. Repeat that until you have a stack of all your coins. Make sure the foil doesn't curl over and touch other layers, though. In the video above the stack of coins puts out 4 volts. To use the battery place a wire on a piece of tape, the battery on top of the wire, and the other wire on the top coin. Wrap the tape around the rest of the coins. If you want, you can add clips to the end of the wire for easier use.