How to make a battery using coins, cardboard and aluminum foil
If you need a battery but don't have any at home, you can try this clever trick for making your own with some everyday household items. It's also a great science experiment to try out with your kids if you want to teach them a bit about physics. All you need are some pennies and a few other things you probably already have at home. The principle behind it is over 2000 years old and explains how modern batteries work.
- 10 pennies
- aluminum foil
- a piece of wire
- crocodile clips
First clean the coins by soaking them in a solution of vinegar and salt. Swish them around in the solution for a few minutes and then dry them off with a paper towel.
Use one of the coins as a stencil to draw nine circles on the cardboard. Cut the circles out using the scissors. (In this example an extra circle was drawn as a spare.)
Soak the cardboard discs in vinegar.
Fold a piece of aluminum foil several times and trace out a circle on it. Cut this out and you'll end up with several foil discs. You'll need at least nine discs.
Now it's time to build the battery. Start by putting down a coin and placing a piece of vinegar-soaked cardboard on it. Place an aluminum foil disc on next and continue in this order until you have used all nine cardboard and aluminum discs. Place another coin on the top.
The battery is basically done and you can see here that it's capable of producing 4 volts of electricity.
To put your battery to use, use tape to secure wires to both ends of the "coin tower."
Secure the crocodile clips to the other ends of the wires. Now you can use your coin battery to power a device that doesn't require a large amount of electricity, e.g. a remote control.
Your coin battery basically works the same as a conventional battery. The acidic vinegar acts as the electrolyte that dissolves the aluminum atoms and sets their electrons free. Metals that release electrons are referred to as "non-noble" and serve as the negative pole. Noble metals such as copper absorb electrons and act as the positive pole.
Normal batteries are made up of carbon (illustration: the black part in the middle) instead of copper, battery acid instead of vinegar (illustration: brown), and zinc instead of aluminum foil (illustration: thin light-gray outer area).
When the wires are attached to a device such as a remote control or LED bulb, the circuit is completed and the electrons are able to flow from the aluminum, through the device and into the copper.
You can watch how it's done step-by-step in this video:
It may be hard to believe, but the oldest battery ever discovered is over 2000 years old. It was found near Baghdad, Iraq, and is made up of a clay pot holding a copper cylinder into which an iron rod is inserted. The pot was most likely filled with lemon juice or vinegar. In this regard it would have worked just like a homemade coin battery.
The only question is: what did people do with a battery 2000 years ago? It's assumed that the "Baghdad battery" was used for electrotherapy treatment. One thing's for sure — it wasn't used to power a remote control. Even if they'd had such a thing back then, they would have needed 10 Baghdad batteries to produce the same amount of electricity as a coin battery!