You can make a simple battery from a citrus fruit such as a lemon, orange or grapefruit. The natural acids in the fruit’s juices act like the chemicals inside store-bought batteries. When the juices react with metals, the electron imbalance generates electricity.
A Simple Process
Citrus acid is the substance that imparts a tart flavor to fruits like oranges and lemons. When combined with water, the citrus acid ionizes. Since the juice in fruits is largely water, a piece of fresh fruit is packed with ions. Combining those ions with strips of metal triggers a chemical reaction that can produce electricity.
Citrus Battery Experiment
To make a battery, obtain a lemon and two small, clean strips of metal, one of copper and another of zinc, roughly 1/2 inch wide and 1 to 3 inches long. Cut the fruit in half, discard or set aside one piece and use the remaining half. Insert the strips in the meat of the fruit so they are at least an inch apart. Connect a voltmeter’s red probe to the copper strip and the black probe to the zinc strip; the meter should read between 1/2 and 1 volt. Note that fruit batteries are weak; a single piece of fruit cannot produce enough electricity to power a light bulb, though it has enough voltage to be read on a meter.