Creating a battery from citrus fruit is a popular experiment in schools and a fascinating project to attempt at home. Low-power items such as LCD clocks or LEDs can be powered for a week from nothing more than a piece of fruit. Batteries consist of two electrodes inserted into an electrolyte solution, and the acidic juice of a lime is a natural electrolyte solution, making it a good source of bio-power.
Squeeze the lime to break up the juice-filled cells within the flesh. Do as much damage to the internal structure as possible but take care not to rupture the skin.
Strip an inch of insulation from one end of the copper wire, then straighten out the paperclip. If either is dirty, corroded, or has a rough edge, clean the metal until it is smooth and shines.
Insert the copper wire into one side of the lime and the paperclip into the other side of the lime. Do not allow the two metals to touch each other. The battery is now ready for use. When the two metal inserts are connected to each other, a low voltage will flow between them.
Connect a multimeter between the metal inserts to measure the voltage.
To avoid a painful squirt of lime juice in your eyes, don't lean over the fruit when pushing probes into it.
Do not eat the lime after it has been used as a battery. The acidic juice dissolves metal from the probes and may contaminate the fruit.