Biological Batteries

Keywords

Biology, battery, citrus fruit, potato, hydrogen ion, cathode, anode, voltage, current.

Introduction

Did you know that as well as using a physical battery in the form of a cell (using lithium ion), you can use certain biological items to make a battery?

Let's find out more.

What Can I Use?

It's true. You can use an everyday item to provide energy to a source. And I don't mean something like a table, or a utensil in your kitchen. So, what can you use?

If you go to the supermarket, you can buy the following shopping list:

• potatoes
• lemons
• limes
• oranges
• grapefruit
• apples

If you get any of those items, you can conduct electricity through them, and even make your own energy source.

How Does This Work?

Well, if you were to place two electrodes into one of the above fruit or vegetables, you would enable it to complete a circuit, and the acids and alkalis inside them create energy.

Still confused? Why not try it? You can get all the items you need from your school, or buy the pieces online, and test the theory yourself.

A boiled potato carries more capacity of energy than a raw potato. At least 10 times the amount.

If you were to connect several fruit or vegetables in a row, it will then create a parallel circuit. This creates more current. If you did the same in a series arrangement, the voltage is then increased.

The Chemistry

Basically, the citrus fruit has acidic juice inside. When you place a copper diode and a zinc anode to it, the juice inside reacts with the terminals. This is on the chemical level of hydrogen ions. If you connect these up using wires, to a lightbulb, it completes a circuit, so then enables power to transfer from the lemon to the bulb.

Applications

While not easy to maintain, or at all economical to use, experimenting with what you could power is interesting. It could power a lightbulb for a sustained amount of time, or get enough fruit, and you could power a simple wristwatch that requires a battery.