Alessandro Volta

Science Dateline: February 18

Physicist Alessandro Volta, inventor of the battery

Alessandro (Giuseppe Antonio Anastasio) Volta was an Italian physicist known for the invention of the battery. He was born on February 18, 1745,  in Como, a town in present-day northern Italy near the Swiss border.

In 1774, he became a professor of physics at the Royal School in Como. He improved and popularized the electrophorus, a device that produced static electricity. He is often credited with its invention although a machine operating on the same principle was described in 1762 by Johan Wilcke, a Swedish experimenter.

Volta's Works

Volta studied the chemistry of gases between the years 1776-78. He discovered methane after reading a paper by Benjamin Franklin on "flammable air." In November, 1776, he found methane at Lake Maggiore. After two years he isolated it.


He devised experiments such as the ignition of methane by an electric spark in a closed vessel. He also studied electrical capacitance, developing separate means to study both electrical potential (V) and charge (Q), and discovered that for a given object, they are proportional. This is what we now know as Volta's Law of capacitance. For his work on this, the unit of electrical potential has been named "volt", after Volta's name.


He became a professor of experimental physics at the University of Pavia in 1779, a chair that he occupied for almost 40 years. In 1794, Volta married an aristocratic lady also from Como, Teresa Peregrini. They had three sons: Giovanni, Flaminio and Zanino.

Volta and Galvani

Luigi Galvani, an Italian physicist, physician and philosopher discovered what he called "animal electricity." This happens when two different metals were connected in series with the leg of a frog and to one another.  Upon realizing that that the frog's leg served as both a conductor of electricity (we now know as "electrolyte") and as a detector of electricity, Volta replaced the frog's leg with brine-soaked paper. He detected the flow of electricity, paving the way to his discovery of the electlrochemical series along with the related 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. This means that two identical electrodes and a common electrolyte give zero net emf. This is what we now know as Volta's Law of the electrochemical series.

The Voltaic Pile Invention / The First Battery

In 1800 Galvani and Volta had professional professional disagreement over the galvanic response that Galvani advocated.  As a result, Volta invented the voltaic pile, an early electric battery, which produced a steady electric current. Volta determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver. Initially he experimented with individual cells in series, he used a wine goblet for each cell filled with brine into which the two dissimilar electrodes were dipped.  Then Volta replaced the goblets with cardboard soaked in brine with the voltaic pile.  His discovery of the voltaic cells becomes the first battery, credited as the first electrochemical cell.

Without going into details about the chemical elements and chemical reaction, simply,the battery 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. Between these two electrodes (terminals), an electric current will flow if they are connected due to the chemical reaction in the voltaic cell.

Last Years of Volta

Volta was made a count by Napoleon Bonaparte in 1801. His image along with a sketch of his well-known voltaic pile was also depicted on the Italian 10,000 lira note although it is no longer in circulation since the lira was replaced by the euro. Volta retired in 1819 to his estate in Camnago, Como, Italy, now named "Camnago Volta." He died March 5, 1827. His remains were also buried there.

Volta's legacy is celebrated by the Tempio Voltiano memorial located in the public gardens by the lake. There is also a museum built in his honor, that exhibits some of the original equipment he used to conduct his experiments. Nearby stands the Villa Olmo, which houses the Voltian Foundation, an organization that promote scientific activities.

Resources:

Alessandro Volta.  IEEE Global History Network/Alessandro Volta.  Accessed 18 February 2014.

Alessandro Volta.  www.famousscientists.org/alessandro-volta/.  Accessed 18 February 2014.

Volta.  www.energyquest.ca.gov.  Accessed 18 Feb 2014.

Inventor of the Week:  Alessandro Volta.  MIT / MIT School of Engineering. Accessed 18 February 2014.



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