Michael Faraday

Encyclopedia : M : MI : MIC : Michael Faraday

---

Michael Faraday, FRS (September 22, 1791 – August 25, 1867) was an English chemist and physicist (he considered himself a natural philosopher) who contributed significantly to the fields of electromagnetism and electrochemistry. He established that magnetism could affect rays of light and that there was an underlying relationship between the two phenomena.

Some historians of science refer to him as the greatest experimentalist in the history of science. It was largely due to his efforts that electricity became viable for use in technology. The SI unit of capacitance, the farad, is named after him, as is the Faraday constant, the charge on a mole of electrons (about 96,485 coulombs). Faraday's law of induction states that a magnetic field changing in time creates a proportional electromotive force.

He held the post of Fullerian Professor of Chemistry at the Royal Institution of Great Britain. Faraday was the first, and most famous, holder of this position to which he was appointed for life.

Career outline

Michael Faraday was born in Newington Butts, near present-day Elephant and Castle in South London, England. His family was poor; his father, James Faraday, was a Yorkshire blacksmith who suffered ill-health throughout his life. As such, Faraday had to educate himself. At fourteen he became apprenticed to bookbinder and seller George Riebau and, during his seven year apprenticeship, read many books, developing an interest in science and specifically electricity. In particular, he enjoyed the book Conversations in Chemistry by Jane Marcet, which inspired him.

At the age of twenty, in 1812, at the end of his apprenticeship, Faraday attended lectures by the eminent English (Cornish) chemist and physicist Humphry Davy of the Royal Institution and Royal Society, and John Tatum, founder of the City Philosophical Society. The tickets were given to Faraday by William Dance (one of founders of the Royal Philharmonic Society). Afterwards, Faraday sent Davy a sample of his notes taken during the lectures. Davy's reply was immediate, kind and favorable. When Davy damaged his eyesight in an accident with nitrogen trichloride, he decided to employ Faraday as a secretary. When John Payne, one of the Royal Institution's assistants, was sacked, the now Sir Humphry Davy was asked to find a replacement, and he appointed Faraday as Chemical Assistant at the Royal Institution on 1 March 1813.

In a class-based society, Faraday was not considered a gentleman. When Davy went on a long tour to the continent in 1813-5, his valet refused to go. Faraday was part of the party as Davy's scientific assistant, and was asked to act as Davy's valet until a replacement could be found in Paris. Davy failed to find a replacement, and Faraday was forced to fill the role of valet as well as assistant throughout the trip. Davy's wife, Jane Apreece, refused to treat Faraday as an equal (making him travel outside the coach, eat with the servants, etc.) and generally made Faraday so miserable he contemplated returning to England alone and giving up science altogether. The trip however did give him access to the European scientific elite and a host of stimulating ideas.

His sponsor and mentor was John 'Mad Jack' Fuller, who created the Fullerian Professorship of Chemistry at the Royal Institution.

Faraday married Sarah Barnard (1800-1879) on 2 June 1821 but they had no children. They met through attending the Sandemanian church.

He was elected membership of the Royal Society in 1824, appointed director of the laboratory in 1825; and in 1833 he was appointed Fullerian professor of chemistry in the institution for life, without the obligation to deliver lectures.

Faraday was also a devout Christian and a member of the small Sandemanian denomination, an offshoot of the Church of Scotland. He served two terms as an elder in the group's church.

Scientific achievements

Chemistry

Faradays earliest chemical work was as an assistant to Davy. He made a special study of chlorine, and discovered two new chlorides of carbon. He also made the first rough experiments on the diffusion of gases, a phenomenon first pointed out by John Dalton, the physical importance of which was more fully brought to light by Thomas Graham and Joseph Loschmidt. He succeeded in liquefying several gases; he investigated the alloys of steel, and produced several new kinds of glass intended for optical purposes. A specimen of one of these heavy glasses afterwards became historically important as the substance in which Faraday detected the rotation of the plane of polarisation of light when the glass was placed in a magnetic field, and also as the substance which was first repelled by the poles of the magnet. He also endeavoured with some success, to make the general methods of chemistry, as distinguished from its results, the subject of special study and of popular exposition.

He invented the earliest form of what was to become the Bunsen burner, which is used almost universally in science laboratories as a convenient source of heat. [The Origin of the Bunsen Burner (pdf)] William B. Jensen , Journal of Chemical Education • Vol. 82 No. 4 April 2005 - Accessed June 2006

Faraday worked extensively in the field of chemistry, discovering chemical substances such as benzene (which he called bicarburet of hydrogen), inventing the system of oxidation numbers, and liquefying gases such as chlorine. He prepared the first clathrate hydrate. Faraday also discovered the laws of electrolysis and popularized terminology such as anode, cathode, electrode, and ion, terms largely created by William Whewell. For these accomplishments, many modern chemists regard Faraday as one of the finest experimental scientists in history.

Electricity

His greatest work was with electricity. The first experiment which he recorded was the construction of a voltaic pile with seven halfpence pieces, stacked together with seven disks of sheet zinc, and six pieces of paper moistened with salt water. With this pile he decomposed sulphate of magnesia (first letter to Abbott, July 12, 1812).

In 1821, soon after the Danish physicist and chemist, Hans Christian Ørsted discovered the phenomenon of electromagnetism, Davy and British scientist William Hyde Wollaston tried but failed to design an electric motor. Faraday, having discussed the problem with the two men, went on to build two devices to produce what he called electromagnetic rotation: a continuous circular motion from the circular magnetic force around a wire and a wire extending into a pool of mercury with a magnet placed inside would rotate around the magnet if supplied with current from a chemical battery. The latter device is known as a homopolar motor. These experiments and inventions form the foundation of modern electromagnetic technology. Unwisely, Faraday published his results without acknowledging his debt to Wollaston and Davy, and the resulting controversy caused Faraday to withdraw from electromagnetic research for several years.

At this stage, there is also evidence to suggest that Davy may have been trying to slow Faraday’s rise as a scientist (or natural philosopher as it was known then). In 1825, for instance, Davy set him onto optical glass experiments, which progressed for six years with no great results. It was not until Davy's death, in 1829, that Faraday stopped these fruitless tasks and moved on to endeavors that were more worthwhile.

Two years later, in 1831, he began his great series of experiments in which he discovered electromagnetic induction, though the discovery may have been anticipated by the work of Francesco Zantedeschi. He found that if he moved a magnet through a loop of wire, an electric current flowed in the wire. The current also flowed if the loop was moved over a stationary magnet.

His demonstrations established that a changing magnetic field produces an electric field. This relation was mathematically modelled by Faraday's law, which subsequently became one of the four Maxwell equations. These in turn evolved into the generalization known as field theory.

Faraday then used the principle to construct the electric dynamo, the ancestor of modern power generators.

Faraday proposed that electromagnetic forces extended into the empty space around the conductor, but did not complete his work involving that proposal. Faraday's concept of lines of flux emanating from charged bodies and magnets provided a way to visualize electric and magnetic fields. That mental model was crucial to the successful development of electromechanical devices which dominated engineering and industry for the remainder of the 19th century.

In 1845 he discovered what is now called the Faraday effect and the phenomenon that he named diamagnetism. The plane of polarization of linearly polarized light propagated through a material medium can be rotated by the application of an external magnetic field aligned in the propagation direction. He wrote in his notebook, "I have at last succeeded in illuminating a magnetic curve or line of force and in magnetising a ray of light". This established that magnetic force and light were related.

In his work on static electricity, Faraday demonstrated that the charge only resided on the exterior of a charged conductor, and exterior charge had no influence on anything enclosed within a conductor. This is because the exterior charges redistribute such that the interior fields due to them cancel. This shielding effect is used in what is now known as a Faraday cage.

Despite his excellence as an experimentalist, his mathematical ability did not extend so far as trigonometry or any but the simplest algebra. However his experimental work was consolidated by the able James Clerk Maxwell who developed his equations which lie at the base of all modern theories of electromagnetic phenomena. Faraday however possessed the gift of the ability to present his ideas in clear and simple language.

Later life

More that a half a century after a teenaged Faraday first visited the Royal Institution, he could still be found there, spending hours watching the sky from his window.

In 1848, as a result of representations by the Prince Consort, Michael Faraday was awarded a Grace and favour house in Hampton Court, Surrey free of all expenses or upkeep. This was the Master Mason's House, later called Faraday House, and now No.37 Hampton Court Road. In 1858 he retired to live there. [http://www.twickenham-museum.org.uk/detail.asp?ContentID=197 Twickenham Museum on Faraday and Faraday House , Accessed June 2006

During his lifetime, Faraday rejected a knighthood and twice refused to become President of the Royal Society.

He died at his house at Hampton Court on August 25, 1867. He has a memorial plaque in Westminster Abbey, near Isaac Newton's tomb, but he turned down burial there and is interred in the Sandemanian plot in Highgate Cemetery.

Miscellaneous

He gave a successful series of lectures on the chemistry and physics of flames at the Royal Institution, entitled The Chemical History of a Candle; this was the origin of the Christmas lectures for young people that are still given there every year and bear his name.

His picture was printed on British £20 banknotes from 1991 until 2001[Bank of England, Withdrawn Notes].

In the Video Game Chromehounds there is a ThermoVision Device named the Farady.

Publications

Published Works by Michael Faraday

• Chemical Manipulation, being Instructions to Students in Chemistry (1 vol., John Murray, 1st ed. 1827, 2nd 1830, 3rd 1842);
• Experimental Researches in Electricity, vols. i. and ii., Richard and John Edward Taylor, vols. i. and ii. (1844 and 1847); vol. iii. (1844); vol. iii. Richard Taylor and William Francis (1855);
• Experimental Researches in Chemistry and Physics, Taylor and Francis (1859);
• A Course of Six Lectures on the Chemical History of a Candle (edited by W. Crookes) (Griffin, Bohn & Co., 1861);
• On the Various Forces in Nature (edited by W. Crookes) (Chatto & Windus, 1873).
• A Course of 6 lectures on the various forces of matter and their relations to each other. edited by William Crookes(1861).
• His Diary edited by T. Martin was published in eight volumes (1932 - 36)

Biographies

• Tyndall, John, Faraday as a Discoverer, (Longmans, 1st ed. 1868, 2nd ed. 1870);
• Jones, Bence Dr. , secretary of the Royal Institution, The Life and Letters of Faraday in 2 vols. (Longmans, 1870);
• Gladstone, J. H. , Ph.D., F.R.S., Michael Faraday, (Macmillan, 1872);
• Thompson, S. P., Michael Faraday; his Life and Work, (1898). (J. C. M.)

References

• "FARADAY." at LoveToKnow 1911 Britannica Online Encyclopedia.[link]

• Hamilton, James (2002). Faraday: The Life. Harper Collins, London. ISBN 0007163762.
• Hamilton, James (2004). A Life of Discovery: Michael Faraday, Giant of the Scientific Revolution. Random House, New York. ISBN 1400060168.
• Thomas, John Meurig (1991). Michael Faraday and the Royal Institution: The Genius of Man and Place Hilger, Bristol. ISBN 0750301457
• Thompson, Silvanus (1901, reprinted 2005) “Michael Faraday, His Life and Work”. Cassell and Company, London, 1901; reprint by Kessenger Publishing, Whitefish, MT. ISBN 1417970367

Notes

Quotations

• "Nothing is too wonderful to be true."
• "Work. Finish. Publish." — his well-known advice to the young William Crookes
• "The important thing is to know how to take all things quietly."
• Regarding the hereafter, "Speculations? I have none. I am resting on certainties. I know whom I have believed and am persuaded that he is able to keep that which I have committed unto him against that day."
• "Next Sabbath day (the 22nd) I shall complete my 70th year. I can hardly think of myself so old."

External links and articles

Biographies

• [Detailed biography of Faraday]
• [IEE biography of Michael Faraday]
• [Faraday as a Discoverer by John Tyndall, Project Gutenberg] (downloads)
• [The Christian Character of Michael Faraday]
• [Biography at The Royal Institution of Great Britain]

Others

• [Michael Faraday Directory]
• (downloads)
• ["Experimental Researches in Electricity" by Michael Faraday] Original text with Biographical Introduction by Professor John Tyndall, 1914, Everyman edition.
• [Video Podcast with Sir John Cadogan talking about Benzene since Faraday]

Further reading

• Ames, Joseph Sweetman (Ed.), "The discovery of induced electric currents" Vol. 2. Memoirs, by Michael Faraday. New York, Cincinnati [etc.] American book company [c1900] LCCN 00005889

See also

• UK topics
• Faraday's Diary, ¶ 7718, 30 September 1845 and ¶ 7504, 13 September 1845

 

---

From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.

Search Titles

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

?