Use Lemon as your Battery

Making a battery using a lemon is a common project that can be found in most science textbook. Successfully creating one of these devices is not easy. Batteries consist of two different metals suspended in an acidic solution.  Copper and Zinc work well as the metals and the citric acid content of a lemon will provide the acidic solution. Batteries like this will not be able to run a motor or energize most light bulbs.  It is possible to produce a dim glow from an LED.

Lemon battery label

Insert a 1cent coin into a cut on one side of the lemon. Then push a galvanized nail into the other side of the lemon. The nail and penny must not touch.

4 Lemon battery

Usually a single lemon battery will produce voltage of about 0.906volts so when you connect 4 of them into series circuit it produce roughly 3.5volts. This is more than enough to make a LED glow. If you fail in your first attempt try to experiment with different zinc and copper (The 1 cent coin may not be purely copper so try experiment with different coin).

via hilaroad