John Henry Poynting (9 September 1852 – 30 March 1914) was an English physicist. He was a professor of physics at Mason Science College, from 1880 to 1900, and then the successor institution, the University of Birmingham until his death.
(An unabridged, unaltered edition in seven parts, to inclu...)
An unabridged, unaltered edition in seven parts, to include: Introductory - On Electromagnetic Induction - General Equations of the Electromagnetic Field - Mechanical Actions in the Field - Theory of Condensers - Electromagnetic Theory of Light - Calculation of the Coefficients of Electromagnetic Induction
James Clerk Maxwell was a British physicist, mathematician, and mechanic. He is popularly known as the Father of Modern Physics and was responsible for making great discoveries in electromagnetism and optics. Maxwell’s Equations are still used to study modern physics.
Background
Maxwell was born on 13 June 1831 at 14 India Street, Edinburgh, to John Clerk Maxwell of Middlebie, an advocate, and Frances Cay, daughter of Robert Hodshon Cay and sister of John Cay. Maxwell was just eight years of age when his mother succumbed to death. He was a smart kid right from his early days.
Education
Maxwell's formal education began under the guidance of a hired tutor, but finding this arrangement less than satisfactory, his father sent his son to the Edinburgh Academy.
Maxwell was captivated by geometry at an early age. Much of his talent went unnoticed however, and his academic work remained unremarkable until, in 1845, at the age of 13, he won the school's mathematical medal, and first prizes for English and for English verse.
Maxwell left the Academy in 1847, and enrolled at the University of Edinburgh. He completed his studies at Edinburgh in natural philosophy, moral philosophy, and mental philosophy under Sir William Hamilton, 9th Baronet.
In 1850, Maxwell left for Cambridge University and initially attended Peterhouse, but eventually left for Trinity College where he believed it would be easier to obtain a fellowship. In November 1851, Maxwell studied under the tutor William Hopkins.
Maxwell graduated with a degree as second wrangler in mathematics from Trinity in 1854, and was declared equal with the senior wrangler of his year in the more exacting ordeal of the Smith's prize examination.
Maxwell accepted a position as a professor of physics at Marischal College, Aberdeen, in 1856. While teaching there, he moved his interest in astronomy and studied the planets. He declared that the Saturn rings are composed of particles. For this particular discovery which was later validated in the 20th-century space exploration, gained Maxwell the Adam Prize.
A few years later, in 1860, he became the professor of natural philosophy at King’s College London. Over the next few years, he experimented on color photography and developed his ideas on the viscosity of gases and proposed what came to be known as dimensional analysis. During the late 1850s and 1860s, he made many noteworthy discoveries in the electric and magnetic fields. His paper "On Physical Lines of Force" was published in 1861. He resigned from King’s College in 1865.
Maxwell published the paper "On Reciprocal figures, frames, and diagrams of forces" in 1870, and the textbook "Theory of Heat" in 1871. In the same year, he became the professor of Experimental Physics at Cambridge and directed the newly created Cavendish Laboratory where the next generation physicists carried forward his work over the next several decades.
Maxwell died on November 5, 1879, at the age of 48. He was buried at Parton Kirk, near Castle Douglas, in Galloway close to where he grew up.
From the start of his childhood, religion touched all aspects of Maxwell's life. Both his father and mother were devout churchgoers (Presbyterian and Episcopalian). The occasional reference to the divine in his writings indicates that his faith was a guiding force in his life.
Maxwell himself was an evangelical protestant. He considered his religion to be a personal affair and showed no deviation between religion and science.
Views
Maxwell is best known for his research in electromagnetic radiation, which unites the sciences of electricity, magnetism and optics. Electricity flows through many metals because of the movement of electrons amongst the atoms of the metal. Moving electrons also produce a magnetic field, the strength of which depends on the number of moving electrons. Electromagnets combine electricity and magnetism within one device, and fluctuating electron movements create electromagnetic waves.
Maxwell saw analogies between the speeds of travel of electromagnetic waves and of light and devised four important mathematical equations that formulated these and other relationships between electricity and magnetism.
Some of Maxwell's results prompted Albert Einstein's research in relativity. Einstein is quoted as saying: "One scientific epoch ended and another began with James Clerk Maxwell."
In 1856, aged 25, Maxwell began work on another field of research - the composition of the rings of Saturn. In Maxwell's time, many astronomers believed that the rings were made of fluid, while Maxwell believed they were made up of small orbiting bodies. To show audiences that it was possible for small orbiting bodies to appear to be fluid, Maxwell devised a model. This was a 'dynamical top' with small balls representing the bodies. When the top was spun fast, it was possible to see what looked like the motion of waves.
Maxwell worked with Austrian physicist Ludwig Boltzmann to develop a theory called the "Maxwell-Boltzmann distribution." This made it possible to determine the speeds of molecules in a gas at different temperatures. Maxwell described a hypothetical situation where gases in a container could be separated into two sections. There was a hot side, where molecules moved fast, and a cold side with slow molecular movement. A tiny imaginary "demon" at a trapdoor would control the flow of molecules between them, producing a perpetual energy source. This would only work if the demon was intelligent enough to distinguish the velocities of the gas molecules without requiring energy itself.
Maxwell wanted to know why mixing different colours of light produces a different result to mixing the same colours of paint. His explanation depended on why we see things being a certain colour. Light from the sun, though appearing white, contains the whole rainbow spectrum of colours. When it hits an object such as grass, all the spectrum is absorbed except green, which is reflected back to the eye. If you mix light, on the other hand, you are adding light beams together - a different process, with different results. Some of Maxwell's experimentation was carried out using a device he made himself - a "colour box" which contained glass prisms and lenses.
Maxwell went on to discover that colour photographs could be formed using red, green, and blue filters. In 1861, Maxwell presented the world's first colour photograph - of a tartan ribbon. Three photos were taken, each time with a different colour filter over the lens. Maxwell developed the images then projected them onto a screen with three different projectors. Each used the same colour filter to take its image. The three images formed a full-colour image. These three photographic plates are now kept in a small museum at 14 India Street, Edinburgh, the house where Maxwell was born.
Quotations:
"In Science, it is when we take some interest in the great discoverers and their lives that it becomes endurable, and only when we begin to trace the development of ideas that it becomes fascinating."
"I have looked into most philosophical systems and I have seen that none will work without God."
"The popularisation of scientific doctrines is producing as great an alteration in the mental state of society as the material applications of science are effecting in its outward life. Such indeed is the respect paid to science, that the most absurd opinions may become current, provided they are expressed in language, the sound of which recals some well-known scientific phrase."
Membership
Maxwell was a Fellow of the Royal Society of Edinburgh (1856); Honorary Fellow of Trinity College, Cambridge University (1871); Member of American Philosophical Society of Philadelphia (1874); Foreign Honorary Member of American Academy of Arts and Sciences in Boston (1874); Member of American Philosophical Society of Philadelphia (1874); Corresponding Member of Royal Society of Sciences of Göttingen (1875); Honorary Member of the New York Academy of Science (1876); Member of Royal Academy of Science of Amsterdam (1877); Foreign Corresponding Member in the Mathematical-Natural-Science Class of the Imperial Academy of Sciences of Vienna (1877).
Royal Society of Edinburgh
,
United Kingdom
1856
American Philosophical Society of Philadelphia
,
United States
1874
American Academy of Arts and Sciences in Boston
,
United States
1874
Royal Society of Sciences of Göttingen
,
Germany
1874
New York Academy of Science
,
United States
1876
Royal Academy of Science of Amsterdam
,
Netherlands
1877
Imperial Academy of Sciences of Vienna
,
Austria
1877
Personality
Maxwell was a smart and bright child from an early age. On the basis of comments stated by his schoolmates, he can be identified as an introvert and not very well-groomed on the outside. Though his intellect was easily visible, he was able to gain respect and admiration from people around in a very less span of time. His interest in physics was one thing but on the personal front he also enjoyed writing poetry which states his creativity.
Maxwell lived a very short span of life of 48 years and in these years he was successful in creating a great identity of his own for which he would be remembered a lifetime influencing upcoming great scientists and physicists.
Quotes from others about the person
"I think a strong claim can be made that the process of scientific discovery may be regarded as a form of art. This is best seen in the theoretical aspects of Physical Science. The mathematical theorist builds upon certain assumptions and according to well understood logical rules, step by step, a stately edifice, while his imaginative power brings out clearly the hidden relations between its parts. A well-constructed theory is in some respects undoubtedly an artistic production. A fine example is the famous Kinetic Theory of Maxwell... The theory of relativity by Einstein, quite apart from any question of its validity, cannot but be regarded as a magnificent work of art.” - Ernest Rutherford.
“One scientific epoch ended and another began with James Clerk Maxwell.” - Albert Einstein.
“From a long view of the history of mankind - seen from, say, ten thousand years from now - there can be little doubt that the most significant event of the 19th century will be judged as Maxwell’s discovery of the laws of electrodynamics.” - Richard Feynman.
“Maxwell is the physicist’s physicist.” - Stephen Hawkins.
“From the outset, Maxwell’s theory excelled all others in elegance and in the abundance of the relations between the various phenomena which it included.” - Heinrich Hertz.
“He achieved greatness unequaled.” - Max Planck.
“The equations were to represent Nature, and Nature is, Maxwell believed, beautiful and elegant… This essentially aesthetic judgment by a nerdish physicist, entirely unknown except to a few other academic scientists, has done more to shape our civilization than any ten recent presidents and prime ministers.” - Carl Sagan.
“The discovery of electrical waves… has had a profound influence on civilization; it has been instrumental in providing the methods which may bring all inhabitants of the world within hearing distance of each other and has potentialities social, educational, and political which we are only beginning to realize.” - J.J. Thomson.
“When he crossed the bridge from Astronomy to Physics he left behind him forever the prospect of becoming a great astronomer – but only to become the greatest mathematical physicist the world has seen since Newton.” - James Jeans.
Interests
poetry
Philosophers & Thinkers
Sir Isaac Newton, Michael Faraday
Politicians
William Hamilton
Writers
Robert Burns
Connections
On June 2, 1858, James Clerk Maxwell married Katherine Mary Dewar. They did not have children.