Alessandro Volta

Alessandro Giuseppe Antonio Anastasio Volta (UK: /ˈvɒltə/, US: /ˈvoʊltə/; Italian: [alesˈsandro dʒuˈzɛppe anˈtɔnjo anasˈtaːzjo ˈvɔlta]; 18 February 1745 – 5 March 1827) was an Italian chemist and physicist who was a pioneer of electricity and power, and is credited as the inventor of the electric battery and the discoverer of methane. He invented the voltaic pile in 1799, and reported the results of his experiments in a two-part letter to the president of the Royal Society, which was published in 1800. With this invention, Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings. Volta's invention sparked a great amount of scientific excitement and led others to conduct similar experiments, which eventually led to the development of the field of electrochemistry.

Volta drew admiration from Napoleon Bonaparte for his invention, and was invited to the Institute of France to demonstrate his invention to the members of the institute. Throughout his life, Volta enjoyed a certain amount of closeness with the emperor who conferred upon him numerous honours. Volta held the chair of experimental physics at the University of Pavia for nearly 40 years and was widely idolised by his students. Despite his professional success, Volta was inclined towards domestic life and this was more apparent in his later years when he tended to live secluded from public life and more for the sake of his family. He died in 1827 from a series of illnesses which began in 1823. The SI unit of electric potential is named the volt in his honour.

Volta was born in Como, a town in northern Italy, on 18 February 1745. His father, Filippo Volta, was of noble lineage. His mother, Donna Maddalena, came from the family of the Inzaghis. In 1794, Volta married an aristocratic lady also from Como, Teresa Peregrini, with whom he raised three sons: Zanino, Flaminio, and Luigi.

In 1774, he became a professor of physics at the Royal School in Como. A year later, he improved and popularised the electrophorus, a device that produced static electricity. His promotion of it was so extensive that he is often credited with its invention, even though a machine operating on the same principle was described in 1762 by the Swedish experimenter Johan Wilcke. In 1777, he travelled through Switzerland, where he befriended the physicist and mountaineer H. B. de Saussure.

In the years between 1776 and 1778, Volta studied the chemistry of gases. He researched and discovered methane after reading a paper by Benjamin Franklin of the United States on "flammable air". In November 1776, he found methane in the marshes of Angera on Lake Maggiore, and by 1778 he managed to isolate it. He devised experiments such as the ignition of methane by an electric spark in a closed vessel.

Volta also studied what we now call electrical capacitance, developing separate means to study both electrical potential difference (V) and charge (Q), and discovering that for a given object, they are proportional. This is called Volta's Law of Capacitance, and for this work, the unit of electrical potential has been named the volt.

In 1779, he became a professor of experimental physics at the University of Pavia, a chair that he occupied for almost 40 years. Volta's lectures were so crowded with students that the subsequent emperor Joseph II ordered the construction (based on a project by Leopold Pollack) of a new "physical theatre", today the "Aula Volta". Furthermore, the emperor granted Volta substantial funding to equip the physics cabinet with instruments, purchased by Volta in England and France. At the University History Museum of the University of Pavia there are 150 of them, used by Alessandro Volta.

Luigi Galvani, an Italian physicist, discovered something he named "animal electricity" when two different metals were connected in series with a frog's leg and to one another. Volta realised that the frog's leg served as both a conductor of electricity (what we would now call an electrolyte) and as a detector of electricity. He also understood that the frog's legs were irrelevant to the electric current, which was caused by the two differing metals. He replaced the frog's leg with brine-soaked paper and detected the flow of electricity by other means familiar to him from his previous studies. In this way, he discovered the electrochemical series, and the law that the electromotive force (emf) of a galvanic cell, consisting of a pair of metal electrodes separated by electrolyte, is the difference between their two electrode potentials (thus, two identical electrodes and a common electrolyte give zero net emf). This may be called Volta's Law of the electrochemical series.