23. MICHAEL FARADAY 1791 - 1867.
This is the age of electricity. It is true that
our era is sometimes called the space age and sometimes called the atomic age;
however, space travel and atomic weapons, whatever their potential importance,
have relatively little impact upon our everyday lives. But we use electrical
devices constantly. In fact, it seems safe to say that no technological feature
so completely permeates the modern world as does the use of electricity.
Many men have contributed to our mastery of
electricity:Charles Augustine de Coulomb, Count
Alessandro Volta, Hans Christian Oersted, and Andre Marie Ampere are among the
most important. But towering far above the others are two great British
scientists, Michael Faraday and James Clerk Maxwell. Though the work of the two
men was in part complementary, they were in no sense collaborators, and each
man's individual achievements entitle him to a high place on this list.
Michael Faraday was born in 1791, in
Newing ton, England. He came from a poor family and was largely self educated. Apprenticed to a bookbinder and bookseller at the age of fourteen, he used the
opportunity to read extensively. When he was
twenty, he attended lectures given by the famous British scientist, Sir Humphry Davy, and was fascinated. He wrote to Davy, and eventually got a job as his assistant. Within a few years, Faraday was making important discoveries of his own. Although he lacked a good background in mathematics, as an experimental physicist he was unsurpassed.
twenty, he attended lectures given by the famous British scientist, Sir Humphry Davy, and was fascinated. He wrote to Davy, and eventually got a job as his assistant. Within a few years, Faraday was making important discoveries of his own. Although he lacked a good background in mathematics, as an experimental physicist he was unsurpassed.
Faraday's first important innovation
in electricity was made in 1821. Two years earlier, Oersted had found that the
needle of an ordinary magnetic compass would be deflected if an electric
current flowed in a nearby wire. This suggested to Faraday that if the magnet
were to be held fixed, the wire might move instead. Working on this hunch, he
succeeded in constructing an ingenious device, in which a wire would rotate
continuously in the vicinity of a magnet as
long as an electric current flowed through the wire. In fact, what
Faraday had invented was the first electric motor, the first device to use an
electric current to make a material object move. Primitive as it was, Faraday's
invention was the ancestor of all the electric motors in use in the world
today.
This was a tremendous breakthrough. However, its practical usefulness was limited, as long as there
was no method of generating electric currents other than the primitive chemical batteries of the day. Faraday was convinced that there must be some way of using magnetism to generate electricity, and he kept looking for such a method. Nov, a stationary magnet will not in duce an electric current in a nearby wire. But in 1831, Faraday discovered that if a magnet is passed through a closed loop of wire, a current will flow in the wire while the magnet is moving. This effect is called electromagnetic induction, and the discovery of the law governing it ("Faraday's law") is generally considered to be Faraday's greatest single achievement.
was no method of generating electric currents other than the primitive chemical batteries of the day. Faraday was convinced that there must be some way of using magnetism to generate electricity, and he kept looking for such a method. Nov, a stationary magnet will not in duce an electric current in a nearby wire. But in 1831, Faraday discovered that if a magnet is passed through a closed loop of wire, a current will flow in the wire while the magnet is moving. This effect is called electromagnetic induction, and the discovery of the law governing it ("Faraday's law") is generally considered to be Faraday's greatest single achievement.
This was
a monumental discovery, for two reasons. First, Faraday's law is of fundamental
importance in our theoretical understanding of electromagnetism. Second,
electromagnetic induction can be used to
generate continuous electric currents, as Faraday himself demonstrated
by building the first electric dynamo. Although the modern electric generators
that supply power to our cities and
factories are far more sophisticated than Faraday's device, they are all based on the same principle
of electromagnetic induction.
Faraday
also made contributions to the field of chemistry. He devised methods for
liquefying gases, and he discovered various chemical substances, including
benzene. Of greater importance is his work in electro chemistry (the study of
chemical effects of electric currents). Faraday's careful experiments
established the two laws of electrolysis which are named after him, and which
form the foundations of electro chemistry. He also
popularized much of the important terminology used in that field, such
as anode, cathode, electrode, and ion.
It was
Faraday who introduced into physics the important idea of magnetic lines of
force and electric lines of force. By emphasizing
not the magnets themselves but rather the field between
them, he helped prepare the way for many advances in modern physics, including
Maxwell's equations. Faraday also discovered that if polarized light is passed
through a magnetic field, its polarization
will be altered. This discovery is significant, because it was the first indication that there is a relationship between
light and magnetism.
Faraday
was not only brilliant, but also handsome, and he was a very popular lecturer
on science. Nevertheless, he was modest and singularly indifferent to fame,
money, and honors. He declined. a knighthood, and also
declined an offer to become president of the
British Royal Society. He had a long, happy marriage, but no children.
He died in 1867, near London.
Faraday lectures at the Royal Institution on December 27, 1855.
No comments:
Post a Comment