Can You Make A Battery Out Of A Potato?

To make a potato battery, you would need the following things:

One large potato
One voltmeter
One steel nail
A small piece of copper wire
Alligator clips

Now, what you need to do is to stick the nail and copper wire into the potato (they should not be touching but should not be very far from each other either. These are our electrodes in this reaction. Connect the electrodes to the voltmeter with alligator clips. Attach the positive end with the copper wire and the negative end with the nail. As soon as this circuit is complete, the voltmeter would give a reading. This reading is usually around half volt for one potato.

If this is for a science project, good luck! :) May be you can even use several potatoes together (connect them together with wires) and use them to light a small bulb! Just replace the voltmeter with the bulb. Remember, you need a very small bulb if you want it to work because the number of volts is not very high.

Yes, you can. You will need: A small flashlight bulb, a bulb holder that will fit your bulb (buy it in hardware store) , 2 electrical lead wires with alligator clips at both ends (also in hardware stores), a knife and an adult's help, a potato, a penny, a galvanized nail.  
Procedure:  1. Screw the flashlight bulb into the bulb holder.
2. Attach one electrical lead wire to each of the terminals on the bulb holder. Make sure you use two different wires!
3. Using the knife, have an adult help you cut two small slits in the potato. Make sure the slits are at least an inch (2.5 cm) apart. Insert the penny into one slit and nail into the other.
4. Attach one of the free alligator clips to the nail.
5. Attach the other free alligator clip to the penny.
6. Watch the lightbulb.
This is a wonder full science project, my daugther did it for her school science fair.

I think so but I don't know how exactly

Uh duh! Look at the top answer

Because of the electrical current that can be found in the potato that charges the wires to make energy.

There is chemical electricity in a potato, when you put the copper wire in the chemical energy is changed to electricity to fuel the clock.