complete cover
Alessandro Giuseppe Antonio Anastasio
Volta (18 February 1745 – 5 March 1827) was
an Italian physicist, chemist, and a pioneer of electricity and power,[2][3][4] who
is credited as the inventor of the electrical battery and the
discoverer of methane. He invented the Voltaic pile in 1799 and the results
of which he reported in 1800 in a two-part letter to the President
of the Royal Society.[5][6] With
this invention Volta proved that electricity could be generated
chemically and debased 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.[6]
Alessandro 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.[1] Alessandro
Volta held the chair of experimental physics at the University of Pavia for nearly
40 years and was widely idolised by his students.[1]
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.[1] The SI unit
of electric potential is named in
his honour as the volt.
Early life and works[edit]
Volta was born in Como, a town in present-day northern Italy (near the Swiss border) 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 own father Filippo Volta was of noble lineage. His
mother Donna Maddalena came from the family of the
Inzaghis.[7]
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.[8][9] 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 United Stateson "flammable air". In
November 1776, he found methane at Lake Maggiore,[10] and
by 1778 he managed to isolate methane.[11] 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 is called Volta's Law of
Capacitance,[12] 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.[1]
Volta and Galvani[edit]
Luigi Galvani, an Italian physicist,
discovered something he named "animal electricity" 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 anelectrolyte) 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, Volta invented
the voltaic pile, an early electric battery, which produced
a steady electric current.[13] 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
withbrine into which the two dissimilar
electrodes were dipped. The voltaic pile replaced the goblets with
cardboard soaked in brine.
First battery[edit]
In announcing his discovery of the voltaic pile, Volta paid tribute
to the influences of William
Nicholson, Tiberius Cavallo, and Abraham Bennet.[14]
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 in the electrochemical
series than both copper and hydrogen, 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.
Last years and
retirement[edit]
Volta explains the principle of the
"electric
column"to
Napoleon in 1801.
In 1809 Volta became associated member of the Royal
Institute of the Netherlands.[15] In
honour of his work, Volta was made a count by Napoleon Bonaparte in
1810.[2] His
image was depicted on the Italian 10,000 lira note 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 honour. He died there on 5 March 1827, just after his 82nd
birthday.[16] Volta's
remains were buried in Camnago Volta.[17]
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 honour, 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.
Religious beliefs[edit]
Volta was raised as a Catholic and for all of his life continued to
maintain his belief.[18] Because
he was not ordained a clergyman as his family expected, he was
sometimes accused of being irreligious and some people have
speculated about his possible unbelief, stressing that "he did not
join the Church",[19] or
that he virtually "ignored the church's call".[20] Nevertheless,
he cast out doubts in a declaration of faith in which he said:
I do not
understand how anyone can doubt the sincerity and constancy of my
attachment to the religion which I profess, the Roman, Catholic and
Apostolic religion in which I was born and brought up, and of which
I have always made confession, externally and internally. I have,
indeed, and only too often, failed in the performance of those good
works which are the mark of a Catholic Christian, and I have been
guilty of many sins: but through the special mercy of God I have
never, as far as I know, wavered in my faith... In this faith I
recognise a pure gift of God, a supernatural grace; but I have not
neglected those human means which confirm belief, and overthrow the
doubts which at times arise. I studied attentively the grounds and
basis of religion, the works of apologists and assailants, the
reasons for and against, and I can say that the result of such
study is to clothe religion with such a degree of probability, even
for the merely natural reason, that every spirit unperverted by sin
and passion, every naturally noble spirit must love and accept it.
May this confession which has been asked from me and which I
willingly give, written and subscribed by my own hand, with
authority to show it to whomsoever you will, for I am not ashamed
of the Gospel, may it produce some good fruit![21][22]
Entdecken Sie den Veranstaltungskalender für Sammler!
Entdecken Sie den Veranstaltungskalender
