Today, batteries are useful if you can’t plug something into an outlet, but when they were first invented they were the only things capable of generating an electric current.
A Bright Spark. Alessandro Volta was born in 1745, when people used candles to light their homes and no one knew what electricity was. He worked as a physicist and, in 1775, he invented a machine that could produce and store static electricity, which he generated by rubbing cat fur across a metal plate.
Volta’s most famous invention came about because of frogs’ legs rather than cat fur. In 1780 a doctor called Luigi Galvani noticed that dissected frogs’ legs twitched when they were brought into contact with two different metals. Galvani thought that this was due to ‘animal electricity’.
Volta realised that the electricity was due to the metal and had nothing to do with the dead frog. He began experimenting and discovered that some metals could generate an electric current if they were submerged in acid.
In 1800 he invented the ‘voltaic pile’, the first ever battery, made from copper and zinc strips separated by paper soaked in salt water and submerged in diluted sulphuric acid. He had worked out a way of generating an electric current.
Volta’s battery was the first portable source of energy and without it radio, telegraph and electric light, among other things, wouldn’t have been possible.
I HAVE THE POWER! Did you know it’s possible to make your own battery using things you can find around the house?
For experiment one you’ll need 4 LEMONS (the bigger the better), 4 TWO PENCE COINS, 4 TWO-INCH NAILS (most nails are coated in ZINC), COPPER WIRE and an LED (Light Emitting Diode). The copper wire, nails and LED can be found in a hardware shop.
In a normal battery, a chemical reaction occurs in the acidic solution within the battery when a circuit is made. In this case the lemon will act as the solution, the nail will be the negative terminal and the coin will be the positive terminal.
Insert a nail in one end of a lemon and a coin in the other: you now have a very basic battery. Unfortunately there is not enough power in this ‘battery’ to light an LED; you need to repeat the instructions above another three times to make four batteries.
Once you’ve made your four batteries, attach them together with the copper wire as shown in the diagram
below. Connect a negative nail terminal to a positive coin terminal on another lemon, and repeat until you have them all joined together with wire, leaving a wire at each end of your lemon line, yet to be connected.
Take an LED and attach the wires to it as shown and it should light up. The LED also has positive and negative terminals too, so make sure you get it the right way round – the negative terminal on the LED has a flat area on the wire just under the bulb.
This time you are going to connect the negative nail terminal in the lemon to the LED’s negative terminal, and the positive coin terminal in the other lemon to the LED’s positive terminal. Congratulations – you’ve made a battery using fruit!
You can also make a battery from vinegar! The vinegar will act in the same way the lemon did in the experiment above. Take an empty plastic container (a tub for camera film is perfect) and pour in some vinegar_ Insert the nail through the top of the lid, then do the same with the copper wire (as shown).
Now this one actually looks more like a battery than the lemon did. Again, one vinegar battery is not enough to power an LED, so make three or four and attach them together as you did with the lemon battery.
It is possible to power a low current calculator with just a few vinegar batteries. Rather than hooking the batteries to an LED, attach two vinegar batteries together, remove the calculator battery and attach the vinegar batteries with wire to the positive and negative terminals in calculator, where the regular battery would have been connected. You should now be able to continue your maths homework!
Special powers: Napoleon was so impressed with Volta’s invention that, in 1801, he invited him to Paris to lecture the French National Institute. He congratulated Volta and even took part in his experiments during the lecture. Later he made Volta a count.