Did you know that you can use a couple of potatoes to power an LED clock?
It is easier than you think.
I can tell you how to make a potato battery, but Im not sure how good my explanation will be!
You will need:
Two large baking potatoes
Two short pieces of quite thick copper wire
Two galvanized iron nails
Three alligator-clip/wire units
An ordinary low-voltage LED clock (one that works on a 1 to 2-volt button-type battery)
This is what you do:
1 Remove the battery from the clock. Make a note of where the positive (+) and negative (-) points of the battery went.
2 Give the potatoes numbers, 1 and 2.
3 Push one nail into each potato.
4 Push one piece of copper wire into each potato, as far away from the nail as possible. Dont push it right in, leave a bit sticking out.
5 Use one alligator clip to connect the copper wire in potato 1 to the positive(+) terminal in the clock's battery compartment.
6 Use one alligator clip to connect the nail in potato number 2 to the negative(-) terminal in the battery compartment.
7 Use the third alligator clip to complete your wire circuit; connect the nail in potato number 1 to the copper wire in potato number 2 and set the clock!
How does it work?
Actually, it works with other fruit/vegetables; lemons, apples etc.
What you are making is an electrochemical battery, or cell.
This is a cell in which chemical energy is changed into electrical energy.
The zinc in the nail reacts chemically with the copper wire.
The potato between the nail and the wire is a sort of buffer, and the reaction can only produce heat, not electricity.
The electron transfer is therefore frustrated, and takes the easiest path, through the wire circuit you made,which delivers electricity to the clock.
I hope you understand this, and apologise if it is not clear.