||This article's lead section may not adequately summarize key points of its contents. (August 2012)|
Alessandro Giuseppe Antonio Anastasio Volta
|Born||18 February 1745
Como, Duchy of Milan
|Died||5 March 1827
|Fields||Physics and chemistry|
|Known for||Invention of the electric cell
Discovery of methane
Early life and works
Volta was born in Como, a town in present-day northern Italy (near the Swiss border) on February 18, 1745. In 1774, he became a professor of physics at the Royal School in Como. A year later, he improved and popularized 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 the years between 1776–78, Volta studied the chemistry of gases. He discovered methane after reading a paper by Benjamin Franklin of America on "flammable air", and Volta searched for it carefully in Italy. In November, 1776, he found methane at Lake Maggiore, and by 1778 he managed to isolate methane. 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 (V ) and charge (Q ), and discovering that for a given object, they are proportional. This may be called Volta's Law of capacitance, and it was 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. In 1794, Volta married an aristocratic lady also from Como, Teresa Peregrini, with whom he raised three sons: Giovanni, Flaminio and Zanino.
Volta and Galvani
Luigi Galvani discovered something he named "animal electricity" when two different metals were connected in series with the frog's leg and to one another. Volta realized 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 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.
In 1800 as the result of a professional disagreement over the galvanic response advocated by Galvani, he invented the voltaic pile, an early electric battery, which produced a steady electric current. Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver. Initially he experimented with individual cells in series, each cell being a wine goblet filled with brine into which the two dissimilar electrodes were dipped. The voltaic pile replaced the goblets with cardboard soaked in brine.
The battery made by Volta is credited as the first electrochemical cell. It consists of two electrodes: one made of zinc, the other of copper. The electrolyte is either sulfuric acid mixed with water or a form of saltwater brine. The electrolyte exists in the form 2H+ and SO42−. The zinc, which is higher than both copper and hydrogen in the electrochemical series, reacts with the negatively charged sulfate (SO42−). The positively charged hydrogen ions (protons) capture electrons from the copper, forming bubbles of hydrogen gas, H2. This makes the zinc rod the negative electrode and the copper rod the positive electrode.
- Zn → Zn2+ + 2e−
- sulfuric acid
- 2H+ + 2e− → H2
The copper does not react, but rather it functions as an electrode for the electric current.
However, this cell also has some disadvantages. It is unsafe to handle, since sulfuric acid, even if diluted, can be hazardous. Also, the power of the cell diminishes over time because the hydrogen gas is not released. Instead, it accumulates on the surface of the zinc electrode and forms a barrier between the metal and the electrolyte solution.
Last years and retirement
In honor of his work, Volta was made a count by Napoleon Bonaparte in 1801. Furthermore, his image was depicted upon the Italian 10,000 lira note (no longer in circulation, since the lira has been replaced by the euro) along with a sketch of his well-known voltaic pile.
Volta retired in 1819 to his estate in Camnago,a frazione of Como, Italy, now named "Camnago Volta" in his honor. He died there on March 5, 1827. Volta's remains were also buried in Camnago Volta.
Volta's legacy is celebrated by the Tempio Voltiano memorial located in the public gardens by the lake. There is also a museum which has been built in his honor, and it exhibits some of the original equipment that Volta used to conduct experiments. Not far away stands the Villa Olmo, which houses the Voltian Foundation, an organization promoting scientific activities. Volta carried out his experimental studies and produced his first inventions near Como.
Volta was raised as a Catholic and for all of his life continued to maintain a strong faith and to attend church.
De vi attractiva ignis electrici (1769) (On the attractive force of electric fire)
- Volta Prize
- Luigi Galvani
- History of the battery
- Volta (lunar crater)
- History of the internal combustion engine
- Lemon battery
- Giuliano Pancaldi, "Volta: Science and culture in the age of enlightenment", Princeton University Press, 2003.
- Alberto Gigli Berzolari, "Volta's Teaching in Como and Pavia"- Nuova voltiana
- Pancaldi, Giuliano (2003). Volta, Science and Culture in the Age of Enlightenment. Princeton Univ. Press. ISBN 978-0-691-12226-7., p.73
- Joh. Carl Wilcke (1762) "Ytterligare rön och försök om contraira electriciteterne vid laddningen och därtil hörande delar" (Additional findings and experiments on the opposing electric charges [that are created] during charging, and parts related thereto) Kongliga Svenska Vetenskaps Academiens Handlingar (Proceedings of the Royal Swedish Science Academy), vol. 23, pages 206-229, 245-266.
- Alessandro Volta, Lettere del Signor Don Alessandro Volta … Sull' Aria Inflammabile Nativa delle Paludi [Letters of Signor Don Alessandro Volta … on the flammable native air of the marshes] (Milan, (Italy): Guiseppe Marelli, 1777).
- "Methane". BookRags. Retrieved 26 January 2012.
- Munro, John (1902). Pioneers of Electricity; Or, Short Lives of the Great Electricians. London: The Religious Tract Society. pp. 89–102.
- Robert Routledge (1881). A popular history of science (2nd ed.). G. Routledge and Sons. p. 553. ISBN 0-415-38381-1.
- Elliott, P. (1999). "Abraham Bennet F.R.S. (1749-1799): a provincial electrician in eighteenth-century England" (PDF). Notes and Records of the Royal Society of London 53 (1): 59–78. doi:10.1098/rsnr.1999.0063.
- "Alessandro Volta". IEEE Global History Network. IEEE. Retrieved 21 July 2011.
- "Volta". Institute of Chemistry - Jerusalem. Archived from the original on 8 April 2009. Retrieved 2009-05-01.
- For a photograph of his gravesite, and other Volta locales, see "Volta's localities". Retrieved 2009-06-20.[dead link]
- "Gli scienziati cattolici che hanno fatto lItalia (Catholic scientists who made Italy)". Zenit.
|Wikimedia Commons has media related to Alessandro Volta.|
- "Alessandro Volta". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.
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- Chisholm, Hugh, ed. (1911). "Volta, Alessandro". Encyclopædia Britannica (11th ed.). Cambridge University Press