Michael Faraday 1791-1867.
In the autumn of 1831
when Michael Faraday performed the initial experiments which resulted in the discovery of the first dynamo, he also described a phenomenon which has yet to be understood in terms of conventional electrical theory. In paragraphs 255, 256, and 257 of his diary , dated December 26, 1831, is described the experiment of cementing a copper disc on top of a cylinder magnet, paper intervening, and supporting the magnet by means of a string so as to rotate axially, with the wires of a galvanometer connected to the edge and axis of the copper plate. When this combination was caused to rotate an electrical potential was found to be created. The polarity and the magnitude of the potential was found to be the same as would occur if the copper plate had moved and the magnet remained still. Faraday spent his latter years pondering the relationship between the situation of magnet and disc rotating together vis-a-vis the situation of fixed magnet and disc rotating independently. He explained the situation by positing the assumption that the magnetic field of a magnet remained stationary in space whilst the metal of the magnet revolved axially. Thus a relative motion would exist between the moving metal of the magnet and the posited stationary flux lines giving rise to the expected potential which results from the motion of a wire through a magnetic field [emphasis added].
Now also known as a "homopolar generator" the profound mystery of the 173 year old "co-rotating Faraday disc-magnet" -- how an electrical current can be created in a conductor which is apparently not moving relative to the source of a magnetic field ! -- is still to this day being hotly debated by physicists and electrical engineers. Or, as Dr. Bruce DePalma elegantly phrased it, " a phenomenon which has yet to be understood in terms of conventional electrical theory." DePalma, an innovative experimental physicist, would go on to invent and build several of his own versions of this remarkable generator.
Michael Faraday's scientific work laid the foundations of all subsequent electro-technology. From his experiments came devices which led directly to the modern electric motor, generator and transformer. Faraday was also the greatest scientific lecturer of his day, who did much to publicise the great advances of nineteenth-century science and technology through his articles, correspondence and the Friday evening discourses which he established at the Royal Institution. The Royal Institution Christmas lectures for children, begun by Faraday, continue to this day.
Michael Faraday was born on 22nd September 1791. At the age of fourteen he was apprenticed to a London bookbinder. Reading many of the books in the shop, Faraday became fascinated by science, and wrote to Sir Humphry Davy at the Royal Institution asking for a job. On 1st March 1813, he was appointed laboratory assistant at the Royal Institution. There Faraday immersed himself in the study of chemistry, becoming a skilled analytical chemist. In 1823 he discovered that chlorine could be liquefied and in 1825 he discovered a new substance known today as benzene. (today an indegredent in petrol)
However, his greatest work was with electricity.
In 1821, the Danish chemist, Orsted, 1777-1851, discovered the phenomenon of Magnetism and Electricity being related.
He had observed that a compass needle had moved after it was nearby a battery that had been turned on to power up a light. He then immediatly thought that there was (correctly) a relationship between magnetism and electricity. In 1802 another person in Italy had observed the same thing but it was concluded to be of no useful value.
Orsted was not the first person to examine the relationship of Electricity and Magnetism. in 1802 Gian Domenico Romagnosi ( his picture is below ), an Italian legal Scholar, Deflected a Magnetic Needle by Electrostatic Charge. An Account of this was published in 1802 in an Italian Newspaper, with no interest, and was overlooked.
No Galvanic Current existed in the set-up and therefore no Electro-Magnetism was present.
There was no relationship placed between Magnetism and Electricity back then - and never understood. Nearly 20 years later Orsted did conclude there was an actual relationship but was unable to take it further. Orsted would be the very first person to correctly conclude a definite relationship between Electricity and Magnetism.
(Hans Christian Orsted's Picture is below - He is definitely a big figure in the overall situation)
Faraday built two devices to produce what he called electromagnetic rotation: that is a continuous circular motion from the circular magnetic force around a wire. Ten years later, in 1831, he began his great series of experiments in which he discovered electromagnetic induction. These experiments form the basis of modern electromagnetic technology. These were 10 years after Orsted had noticed the relationship between electricity and magnetism.
On 29th August 1831, using his "induction ring", Faraday made one of his greatest discoveries - electromagnetic induction: the "induction" or generation of electricity in a wire by means of the electromagnetic effect of a current in another wire. The induction ring was the first electric transformer. In a second series of experiments in September he discovered magneto-electric induction: the production of a steady electric current. To do this, Faraday attached two wires through a sliding contact to a copper disc. By rotating the disc between the poles of a horseshoe magnet he obtained a continuous direct current. This was the first generator.
Although neither of Faraday's devices is of practical use today ( see Tesla Link below) they enhanced immeasurably the theoretical understanding of electricity and magnetism. He described these experiments in two papers presented to the Royal Society on 24th November 1831, and 12th January 1832. These were the first and second parts of his "Experimental researches into electricity" in which he gave his "law which governs the evolution of electricity by magneto-electric induction".
After reading this, a young Frenchman, Hippolyte Pixii, constructed an electric generator that utilised the rotary motion between magnet and coil rather than Faraday's to and fro motion in a straight line.
All the D.C. generators today are direct descendants of the machine developed by Pixii from Faraday's first principles.
His Picture is above. He is another major trailblazer. Very forgotten. Sad.
A.C. Alternators were invented by Nikola Tesla in the later 1800's (see TESLA link)
A.C. Power generation and distribution is the electricity we use in our houses and workplaces today.
Faraday continued his electrical experiments. In 1832 he proved that the electricity induced from a magnet, voltaic electricity produced by a battery, and static electricity were all the same. He also did significant work in electrochemistry, stating the First and Second Laws of Electrolysis. This laid the basis for electrochemistry, another great modern industry.
Faraday's "descriptive theory of lines of force moving between bodies with electrical and magnetic properties" enabled
James Clerk Maxwell
to formulate an exact mathematical theory of the propagation of electromagnetic waves.
In 1865, Maxwell proved mathematically that electromagnetic phenomena are propagated as waves through space with the velocity of light, thereby laying the foundation of radio communication,
confirmed experimentally in 1888 by Hertz,
And developed for practical use by Tesla and Marconi at the turn of the century.
In 1865, Faraday ended his connection with the Royal Institution after over 50 years of service. He died at his house at Hampton Court on 25th August 1867.
His discoveries have had an incalculable effect on subsequent scientific and technical development. He was a true pioneer of scientific discovery.
Updated September 2014
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