Note: Pennies minted prior to 1982 are best as they are solid copper (Cu). Since then, pennies are just copper plated zinc, and often the copper has worn off high spots like Lincoln's beard, nose and the rim. 1943 pennies are steel. 5 Clean and smooth a piece of ordinary aluminum (Al) foil. Cut a roughly 2.0 cm diameter disk from it (use a penny for a pattern). Next, cut a 2.5 cm diameter disk from a paper towel (use a quarter for a pattern). Moisten the towel, sprinkle on some salt and place it between a penny and the foil disk. Similarly, prepare two other cells. .a Connect the cells in series by stacking them: place the foil of one cell in contact with the penny of the next. Take care not to allow the paper towel insulating one battery to droop onto the next cell. What is the output voltage of the 3 battery you have made? .b Try to activate an inexpensive LCD [the copper penny at one end forms the positive terminal and the aluminum foil the negative) with your 3 battery. Because of the limited current capacity of this simple battery, it usually requires a small storage capacitor of about 10 UF across it to provide sufficient current to allow the watch to change states. Caution: Be sure to halt the electrochemcial reactions after you conclude your procedures by throughly rinsing all the metallic non-consumable materials (ie, nails, meter test leads, etc) with water. Be sure to dry the materials with a paper towel to minimize possibility of rusting. Also, remember to always turn off the DMM after use