Inventions and discoveries
In 1775, Volta invented the
electrophorus, a device that produced a static electric charge. In 1776-
77 he studied the
chemistry of
gases, discovered
methane, and devised experiments such as the
ignition of gases by an electric
spark in a closed vessel. Volta also studied what we now call capacitance, developing separate means to study both electrical potential V and charge Q, and to discovering that for a given object they are proportional. This may be called Volta's Law of
Capacitance, and likely for this work the unit of electrical potential has been named the
volt.
In 1779 he became professor of experimental physics at the University of
Pavia, a chair he occupied for almost 40 years. In 1794, Volta married the daughter of Count Ludovico Peregrini, Teresa, with whom he raised three sons. Each of his three sons went on to improve on the Voltaic Pile in ways that all ended in strait ends.
Around 1791 he began to study the "animal electricity" noted by
Galvani when two different metals were connected in series with the frog's leg and to one another. He realized that the frog's leg served as both a conductor of electricity (we would now call it an
electrolyte) and as a detector of electricity. He replaced the frog's leg by brine-soaked paper, and detected the flow of electricity by other means familiar to him from his previous studies of electricity. 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 of their two electrode potentials. That is, if the electrodes have emfs <math>\mathcal{E}_{1,2}</math>, then the net emf is <math>\mathcal{E}_{2}-\mathcal{E}_{1}</math>. (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
Luigi 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 electric pile replaced the goblets with cardboard soaked in brine. (The number of cells, and thus the voltage it could produce, was limited by the pressure, exerted by the upper cells, that would squeeze all of the brine out of the cardboard of the bottom cell.)
In announcing his discovery of the pile, Volta paid tribute to the influences of
William Nicholson, Tiberius Cavallo and
Abraham Bennet.
he later discovered the volt