Fruit-powered clock, 1998.
© Science Museum / Science & Society Picture Library
Using Alesandro Volta's (1745-1827) original design for a battery, this clock is powered by a fruit or vegetable which provides the acid paste, or electrolyte. Volta was an Italian physicist and the nventor of the voltaic pile, the first battery. This consisted of two different metals, separated by chemicals in order to enable a flow of electricity. It had previously been thought by the Italian scientist Luigi Galvani (1737-1798 ) that animal tisue was necesary to generate electricity. Volta has the unit of electromotive force, the 'volt', named after him.