Alessandro Volta (18 February 1745 – 5 March 1827) was an Italian physicist, chemist and lay Catholic who was a pioneer of electricity and power who is credited as the inventor of the electric battery and the discoverer of methane.

His family was part of the nobility, but not wealthy. Until the age of four, he showed no signs of talking, and his family feared he was not very intelligent or possibly dumb. Fortunately, their fears were misplaced.

His father died leaving unpaid debts when Alessandro was seven. The young Alessandro was educated at home by his uncle until he was twelve years old. He then started studies at a Jesuit boarding school. The Jesuit school charged no fees, but pressurized him to become a priest. His family did not want this, and withdrew him from the school after four years. Volta then studied at the Benzi Seminary until reaching eighteen years of age.

Volta’s family wanted him to become a lawyer. Volta had his own ideas! He was interested in the world around him; he wanted to be a scientist.

Although as a child he had been slow to speak Italian, Volta now seemed to have a special talent for languages. Before he left school, he had learned Latin, French, English, and German. His language talents helped him in later life when he traveled with the aim of discussing his work with scientists in Europe’s centers of science.

Aged 18, Volta was bold enough to begin an exchange of letters about electricity with two leading physicists: Jean-Antoine Nollet in Paris, and Giambatista Beccaria in Turin. Beccaria did not like some of Volta’s ideas and encouraged him to learn more by doing experiments.

He invented the voltaic pile in 1799, and reported the results of his experiments in 1800 in a two-part letter to the president of the Royal Society. 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 also 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. Volta enjoyed a certain amount of closeness with the emperor throughout his life and he was conferred numerous honours by him. 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 tended to be a person inclined towards domestic life and this was more apparent in his later years. At this time he tended to live secluded from public life and more for the sake of his family until his eventual death in 1827 from a series of illnesses which began in 1823. The SI unit of electric potential is named in his honour as the volt.

Early Life

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

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. There he befriended 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 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 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 theater", 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.

Volta and Galvani

Volta did not set out to invent the battery. His experiments in this area were actually performed to show the claims of another scientist were wrong. That scientist was another Italian, Luigi Galvani.

Galvani discovered 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.

In 1817, this inspired Mary Shelley to write Frankenstein. In this novel, a creature made of a monstrous mixture of body parts from dead people is brought to life by Doctor Frankenstein using electricity from a lightning storm.

In 1791, Galvani announced his discovery of animal electricity. He believed that animals generated electricity in their bodies and that a fluid within their nerves carried electricity to muscles, causing movement. He believed that electricity from an outside source released a flow of electrical fluid from the nerves, causing the muscles to jump.

He also believed that animals such as electric eels could build up extra amounts of this fluid and use it to deliver electric shocks.

Galvani concluded that animal electricity was similar but not identical to static electricity, and was a unique property of living things.

In 1800, as the result of a professional disagreement over the galvanic response advocated by Galvani, Volta 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 copper. 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 Early Battery

In announcing his discovery of the voltaic pile, Volta paid tribute to the influences of William Nicholson, Tiberius Cavallo, and Abraham Bennet.

The battery made by Volta is credited as one of the first electrochemical cells. 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 2 H+ and SO2−4. Zinc metal, which is higher in the electrochemical series than both copper and hydrogen, is oxidized to zinc cations (Zn2+) and creates electrons that move to the copper electrode. The positively charged hydrogen ions (protons) capture electrons from the copper electrode, forming bubbles of hydrogen gas, H2. This makes the zinc rod the negative electrode and the copper rod the positive electrode. Thus, there are two terminals, and an electric current will flow if they are connected.

Copper metal does not react, but rather it functions as a catalyst for the hydrogen-gas formation and an electrode for the electric current. The sulfate anion (SO2−4) does not undergo any chemical reaction either, but migrates to the zinc anode to compensate for the charge of the zinc cations formed there. 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 copper electrode and forms a barrier between the metal and the electrolyte solution.

Volta's famous paper of 1800, “On the Electricity Excited by the Mere Contact of Conducting Substances of Different Kinds,” gives instructions for the construction of a voltaic pile or electric battery. It consists of succession of silver and zinc disks in contact with each other. Between each set of metal disks is placed a disk of pasteboard or absorbent material, a bit smaller than the metal disks so as not to overlap them, soaked in salt water. The series is repeated in a vertical column, or pile, for as many times as is convenient. The greater number of series in the pile, the greater is the electrical effect when the top and the bottom of the pile or battery are connected by means of a conductor, or even by a person's moistened extremities, when it delivers a shock.

Because the pasteboard would sometimes dry out, Volta alternatively suggests using a series of cups filled with salt water instead of pasteboard disks. Volta also mentions the use of copper and tin as alternating metals instead of silver and zinc.

Volta revolutionized science and technology by his relatively simple invention of the electric battery. This brainstorm did not occur from thin air, however. Volta had long studied electrical phenomena, and had already won a reputation in the field. He investigated the battery for four years before he made his results public.

Even in his youth, Volta began correspondence with famous scientists, and later in life traveled widely to cement associations and keep abreast of the latest findings. While the battery appears to be a simple innovation, it was developed by one with great knowledge of and interest in the subject of electrical action.

The invention of the battery inspired research in a wide range of scientific fields, from chemistry to physics to medicine, and laid the foundation for the age of electronics.

1777 – Volta invented a much better eudiometer than any that had gone before. A eudiometer tests how much oxygen is present in air to determine how good for breathing it is. Volta’s eudiometer was superior to others because it used hydrogen as the gas reacting with oxygen, giving a clean, reliable reaction. The reaction was also cleanly started using an electric spark. The eudiometer worked on the basis that the volume of hydrogen gas in it decreased after sparking because the hydrogen reacted with oxygen gas to make water. The decrease in volume was proportional to the amount of oxygen present in the air.

1777 – Volta set out on a scientific journey to Switzerland and France. He met other scientists and showed them his innovations in electrical equipment. He also traveled with the purpose of making his name better known outside Italy.

1778 – Volta was appointed to the Chair of Experimental Physics at the University of Pavia, about 55 miles (85 km) from Como, a position he would hold for over 40 years.

1778 – Volta discovered that the electrical potential (we now often call this the voltage) in a capacitor is directly proportional to electrical charge.

1781 to 1782 – Volta traveled around most of Europe’s major scientific centers, including the French Academy in Paris, demonstrating his electrical equipment and inventions to eminent people such as Antoine Lavoisier and Benjamin Franklin. Volta was beginning to become well-known outside Italy.

1782 – Volta wrote about the condenser he had constructed (today we would call it a capacitor) to collect and store electric charge, and how he had used it to study a variety of electrical phenomena.

1788 – Volta built increasingly sensitive electroscopes to detect and measure the effects of electric charge.

1790 – Volta carried out experiments on the behavior of gases. He found an accurate value for air’s increasing volume with rising temperature.

1791 – Recognizing that he had become one of Europe’s foremost electrical scientists, Volta was elected to be a Fellow of the Royal Society of London.

1794 – At the age of 50, Volta was awarded the Royal Society’s top prize – the Copley Medal – for his contributions to scientific understanding of electricity.