Place a whole lemon on the table. Push your hand onto it gently and start to roll back and forth to loosen up the juices inside.
Insert a straightened, large paperclip inside the lemon. Only put it in about an inch.
Cut a piece of 18 gauge wire down to six inches using wire cutters. Insert this an inch into the lemon, as well, but be sure it's not touching the paperclip.
Attach the wire in the lemon and the paperclip to the wires on a multi-tester. This device will test the electrical currents being produced by the lemon.
Disconnect the wire and paperclip from the multi-tester and attach them instead to the base of a light bulb. The electric current from the lemon will now be able to light up the light bulb, demonstrating the strength of the current and its ability to produce power.