Published On:2014/10/08
Posted by alialsayed
Alessandro Volta
Alessandro Giuseppe Antonio Anastasio Volta (February 18, 1745 – March 5, 1827) was an Italian physicist.
known for the invention of:
• Invented in 1800 the first electrical battery – which people called the “voltaic pile.” With this invention, scientists could produce steady flows of electric current, unleashing a wave of new discoveries and technologies.
• Was the first person to discovered and isolate methane.
• Discovered methane mixed with air could be exploded using an electric spark.
• Discovered “contact electricity” resulting from contact between different metals.
• Recognized two types of electric conduction.
• Wrote the first electromotive series. This showed, from highest to lowest, the voltages that metals produce in a voltaic pile. (We now talk of standard electrode potentials, meaning roughly the same thing.)
• Discovered that electric potential in a capacitor is directly proportional to electric charge.
In recognition of Alessandro Volta’s contributions to electrical science, the unit of electric potential is called the volt.
In recognition of Alessandro Volta’s contributions to electrical science, the unit of electric potential is called the volt.
Early Life and Education
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.
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.
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.
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.
Jumping Frogs’ Legs
Galvani was a professor of anatomy. In the late 1780s he noticed that a spark of static electricity carried by a metal scalpel touching the nerves of a dead frog while the legs lay on metal caused the legs to move.
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| Matteucci's frog battery, 1845 (top left); Aldini's frog battery, 1818 (bottom); apparatus for controlled exposure of gases to frog battery (top right). |
This was an amazing discovery: animal movement was based on electricity in some way.
In 1817, this led to Mary Shelley writing Frankenstein. In this novel, a creature made from 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 animals’ 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 to static electricity, but it was different and was a unique property of living things.
Volta studied Galvani’s phenomenon.
In 1792, Volta said that the “animal” part of Galvani’s animal electricity was not needed. Animals merely responded to normal electricity. There was no difference between animal electricity and electricity.
Volta performed various experiments on frogs’ legs. He found the key to getting them to move was contact with two different metals. Contact with pieces of the same metal did nothing.
Then, moving away from frogs’ legs, in 1794, Volta did experiments to measure the electrical effect of bringing different pairs of metals into contact. He listed the metals in order of what he called their electromotive force.
First battery
In announcing his discovery of his voltaic pile, Volta paid tribute to the influences of William Nicholson, Tiberius Cavallo, and Abraham Bennet.[9]
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.
Thus, there are two terminals, and an electric current will flow if they are connected. The chemical reactions in this voltaic cell are as follows:
zinc
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.
Volta Retirement
In honor of his work, Volta was made a count by Napoleon Bonaparte in 1810. His image was depicted on the Italian 10,000 lira note (no longer in circulation, since the euro has replaced the lira) along with a sketch of his 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 buried in Camnago Volta.
The language of experiment is more authoritative than any reasoning: facts can destroy our ratiocination—not vice versa
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, which exhibits some of the equipment that Volta used to conduct experiments. Nearby 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.
The End
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| Volta explains the principle of the 'Electric Column' to Napoleon |
In 1819, at the age of 74, Volta decided it was time to hang up his capacitors, his voltaic piles, his electrophorus, and his administrative work at the university. He retired to a country house close to his home town of Como, where he could spend more time with his wife, Maria Teresa. They had three sons, Zanino, Faminio and Luigi.
Volta lived in Como until his death, aged 82, on March 5, 1827.
In 1881, scientists decided that the unit of electric potential would be called thevolt to recognize Volta’s great contributions to electrical science.
