John Henry Poynting FRS (9 September 185230 March 1914) was an English

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

. He was the first professor of physics at

Mason Science College Mason Science College was a university college in Birmingham, England, and a predecessor college of Birmingham University. Founded in 1875 by industrialist and philanthropist Sir Josiah Mason, the college was incorporated into the University o ...

from 1880 to 1900, and then the successor institution, the

University of Birmingham The University of Birmingham (informally Birmingham University) is a Public university, public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen's College, Birmingha ...

until his death.

Biography

Poynting was the youngest son of Thomas Elford Poynting, a Unitarian minister. He was born at the parsonage of the Monton Unitarian Chapel in Eccles, Lancashire (his father serving as minister there from 1846 to 1878.) In his boyhood he was educated at the nearby school operated by his father. From 1867 to 1872 he attended

Owens College Owens may refer to: Places in the United States * Owens Station, Delaware * Owens Township, St. Louis County, Minnesota * Owens, Missouri * Owens, Ohio * Owens, Virginia People * Owens (surname), including a list of people with the name * Ow ...

, now the

University of Manchester , mottoeng = Knowledge, Wisdom, Humanity , established = 2004 – University of Manchester Predecessor institutions: 1956 – UMIST (as university college; university 1994) 1904 – Victoria University of Manchester 1880 – Victoria Univ ...

, where his physics teachers included

Osborne Reynolds Osborne Reynolds (23 August 1842 – 21 February 1912) was an Irish-born innovator in the understanding of fluid dynamics. Separately, his studies of heat transfer between solids and fluids brought improvements in boiler and condenser design. ...

and

Balfour Stewart Balfour Stewart (1 November 182819 December 1887) was a Scottish physicist and meteorologist. His studies in the field of radiant heat led to him receiving the Rumford Medal of the Royal Society in 1868. In 1859 he was appointed director of K ...

. From 1872 to 1876 he was a student at

Cambridge University The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209 and granted a royal charter by Henry III of England, Henry III in 1231, Cambridge is the world' ...

, where he attained high honours in mathematics after taking grinds with

Edward Routh Edward John Routh (; 20 January 18317 June 1907), was an English mathematician, noted as the outstanding coach of students preparing for the Mathematical Tripos examination of the University of Cambridge in its heyday in the middle of the ninet ...

. In the late 1870s he worked in the Cavendish Laboratory at Cambridge under

James Clerk Maxwell James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and scientist responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and li ...

. In 1880, he became the first professor of physics at the

. He was the developer and

eponym An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''. Usage of the word The term ''epon ...

of the Poynting vector, which describes the direction and magnitude of

electromagnetic In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...

energy flow and is used in the Poynting theorem, a statement about energy conservation for

electric Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

and magnetic fields. This work was first published in 1884. He performed a measurement of Newton's gravitational constant by innovative means during 1893. In 1903 he was the first to realise that the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

's radiation can draw in small particles towards it: this was later named the Poynting–Robertson effect. He discovered the torsion-extension coupling in finite strain elasticity. This is now known as the (positive)

Poynting effect The Poynting effect may refer to two unrelated physical phenomena. Neither should be confused with the Poynting–Robertson effect. All of these effects are named after John Henry Poynting, an English physicist. Solid mechanics In solid mecha ...

in torsion. Poynting and the Nobel prizewinner

J. J. Thomson Sir Joseph John Thomson (18 December 1856 – 30 August 1940) was a British physicist and Nobel Laureate in Physics, credited with the discovery of the electron, the first subatomic particle to be discovered. In 1897, Thomson showed that ...

co-authored a multi-volume undergraduate physics textbook, which was in print for about 50 years and was in widespread use during the first third of the 20th century. Poynting wrote most of it. He was awarded an honorary MSc in Pure Science in 1901 by

Birmingham University , mottoeng = Through efforts to heights , established = 1825 – Birmingham School of Medicine and Surgery1836 – Birmingham Royal School of Medicine and Surgery1843 – Queen's College1875 – Mason Science College1898 – Mason Univers ...

. Poynting lived at 11 St Augustine's Road,

Edgbaston Edgbaston () is an affluent suburban area of central Birmingham, England, historically in Warwickshire, and curved around the southwest of the city centre. In the 19th century, the area was under the control of the Gough-Calthorpe family a ...

with his family and servants for some years. He previously lived at 66 Beaufort Road,

(demolished) and died of a diabetic coma, aged 61, at 10 Ampton Road, Edgbaston in 1914. In 1880 he married Maria Adney Cropper. He was survived by his widow, a son, and two daughters.

Legacy

Alfred J. Lotka was among Poynting's most famous students, being inspired by Poynting to apply the ideas of physical chemistry to biology. Lotka dedicated his classic book on mathematical population biology to Poynting. Poynting predicted the `Poynting-Robertson effect', whereby a particle of dust orbiting a star experiences a drag force which makes it spiral slowly into the star. Howard P. Robertson later restated the prediction using General Relativity. Poynting also founded and is the namesake of the popular student society at the University of Birmingham, 'The Poynting Physical Society' or PPS. University of Birmingham - Poynting Physics Building - Poynting 02

University of Birmingham - Poynting Physics Building - Poynting 02

Unitarian Church, Monton, Blue plaque - geograph

Craters on

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

and the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

are named in his honour, as is the main Physics building at the

and the departmental society there, the Poynting Physical Society. He is credited with coining the expression "

greenhouse effect The greenhouse effect is a process that occurs when energy from a planet's host star goes through the planet's atmosphere and heats the planet's surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly ...

" in 1909 to explain how infrared-absorbing trace gasses such as carbon dioxide in the atmosphere increases the surface temperature of Earth and Mars.

Works by J. H. Poynting

* 1884 ''A Comparison of the Fluctuations in the Price of Wheat and in the Cotton and Silk Imports into Great Britain'', ''Journal of the Royal Statistical Society''; 47, 1884, pp. 34–64 * 189
''The Mean Density of the Earth''
London, C. Griffin * 1899 (with J. J. Thomson) ''A Text-Book of Physics: volume I: Sound'' London, C. Griffin
2nd edition, 1900
* 1902 (with J. J. Thomson
''A Text-Book of Physics: volume II: Properties of Matter''
London, C. Griffin * 1904 (with J. J. Thomson
''A Text-Book of Physics: volume III: Heat''
London, C. Griffin * 191
''The earth; its shape, size, weight and spin''
Cambridge University Press * 1914 (with J. J. Thomson
''A Text-Book of Physics: volume IV: Electricity and Magnetism. Pts. I and II: Static electricity and magnetism''
London, C. Griffin * 192
''Collected Scientific Papers''
Cambridge University Press

References

External links

* * * {{DEFAULTSORT:Poynting, John Henry 1852 births 1914 deaths English physicists Academics of the University of Birmingham Royal Medal winners Fellows of the Royal Society Presidents of the Physical Society