1791 & 1799 – Italy
‘Galvani: An electric current is produced when an animal tissue comes into contact with two different metals.
Volta: An electric current is not dependent on an animal tissue and can be produced by chemicals’
Galvani was wrong and Volta was right.
Galvani had found that by touching a dead frog’s legs with two different metal implements, the muscles in the frog’s legs would twitch. Galvani wrongly concluded it was the animal tissue that was storing the electricity, releasing it when touched by the metals. He felt he had discovered the very force of life – ‘animal electricity’ – that animated flesh and bone.
Soon dozens of scientists were trying to bring corpses back to life by electrifying them. Volta was not convinced the animal muscle was the important factor in the production of the current.
He repeated Galvani’s experiments and concluded, controversially at the time, the different metals were the important factor.
A bitter dispute arose as to whose interpretation was correct. Volta began putting together different combinations of metals to see if they produced any current; later he produced a wet battery of fluid and metals. Volta’s method of producing electric current involved using discs of silver and zinc dipped in a bowl of salt solution. He reasoned that a much larger charge could be produced by stacking several discs separated by cards soaked in salt water – by attaching copper wires to each end of the ‘pile’ he successfully obtained a steady current.
The ‘voltaic pile’ was the first battery in history (1800). Napoleon Bonaparte, who at the time controlled the territory in which Volta lived, was so impressed he made him a Count and awarded him the Legion d’Honour.
Volt, the SI unit of electric potential, honours Volta.
Although Galvani’s theory on ‘animal electricity’ was not of any major importance, he has also achieved nominal immortality; like ‘volt’, the words ‘galvanic’ (sudden and dramatic), ‘galvanised’ (iron or steel coated with zinc) and ‘galvanometer’ (an instrument for detecting small currents) have become part of everyday language.
A volt is defined as the potential difference between two points on a conductor carrying one ampere current when the power dissipated between the points is one watt.