How to make a battery using Pencil Lead, Screw and Lemon

As Lemon has acidic juice, it can be used to make a small battery along with two other metal electrode. This video demonstrates what happened if you use different anode and cathode material. A pencil lead as anode and a galvanized screw as cathode can provide 1.1V. Many other fruits or vegetable can be used instead of lemon, like potato, tomato, ginger, onion, grapes and orange.

Copper - Anode +
Aluminum - Cathode -
Voltage = 0.55V