A lemon-powered light bulb is a great science project or even a great green solution for camping or power outages. The acid in a lemon causes a chemical reaction when metals are inserted into the lemon, resulting in an electrical current. With a handful of lemons and some super-bright LEDs, you can create useful lemon-powered light bulbs that will last for a shocking amount of time.
Take two lemons and roll them on a table, applying pressure with the palm of your hand. This will cause the juices to release from the pulp so you can get a good "battery" for your light bulb. Make sure they get good and soft without breaking the peels.
Cut two lengths of stiff copper wire, several inches long. Press one of the wires into each of the lemons.
Unfold the large steel paper clips. Press one into each of the lemons.
Using the thin copper wire, connect the copper post in the first lemon to the steel post in the second lemon. Then connect the remaining two posts to the light bulb.