Credit for the invention of the battery is usually given to the Italian scientist, Alessandro Volta. In 1799 he invented the ‘Voltaic Pile’ and famously demonstrated it to Emperor Napoleon Bonaparte.
Credit for the invention of the battery is usually given to the Italian scientist, Alessandro Volta. In 1799 he invented the ‘Voltaic Pile’ and famously demonstrated it to Emperor Napoleon Bonaparte.
His primitive battery consisted of a pile of silver and zinc disks separated by a porous, non-conductive substance saturated in sea water, which is an excellent conductor of electricity.
Volta’s invention built on earlier research by another Italian scientist, Luigi Galvani, who noticed that the leg of a dead frog began to twitch when it came in contact with two different metals.
He concluded that there must be a connection between electricity and muscle (chemical) activity, which eventually lead to an understanding of the relationship between electrical energy and chemical reactions.
Understanding how electricity works was vital to the development of the first battery. Galvani and Volta are remembered today in the scientific terms ‘galvanometer’, ‘galvanic cell’, ‘volt’ and ‘photovoltaic cell’. Recent discoveries have suggested, however, that a simple battery may have been invented by Arabic people near Baghdad over 1 000 years before Volta!
In 1936 some 130-centimetre terracotta pots with mouths about four centimetres wide were discovered near Baghdad.
Inside the pots were copper cylinders comprising rolled up copper sheets, each of which housed a single iron rod.
At the top, the iron rod was isolated from the copper by a bitumen plug, all of which fitted snugly into the pot.
As the copper cylinder is not watertight, any liquid in the jar would also surround the iron rod.
The director of the National Museum of Iraq, Dr Wilhelm König, studied the jars and concluded that they might be primitive batteries that were used to electroplate gold onto silver.
König speculated that if the jars were filled with an acidic liquid, such as grape or lemon juice, or vinegar, which was readily available at that time, this liquid could act as an electrolyte that would generate an electric current between the copper and iron electrodes.
The jars have been dated at about 640 CE, i.e. over 1 300 years ago, and more than 1 000 years before Volta.
König had previously found fine silver objects with very thin layers of gold coating their surfaces, and had wondered how this had been achieved by ancient technologists.
Now he appeared to have the answer! After 1945 several scientists tested König’s idea and confirmed that this simple battery design could produce sufficient electric current for electroplating.
In 2005 the Discovery Channel programme Myth Busters made 10 terracotta jars and fitted them out as batteries in the same way as the original jars.
They used lemon juice as the electrolyte to produce the electrochemical reaction.
To their amazement, they found that if they connected all the ‘Baghdad Batteries’ in series, about four volts of electricity could be produced!
Not everyone is convinced that the jars from Baghdad were batteries, but hey, that is the essence of science – a healthy disrespect for the views of experts!
