John Strutt, 3rd Baron Rayleigh

Lord Rayleigh
John William Strutt, 3rd Baron Rayleigh
Born	12 November 1842(1842-11-12) Langford Grove, Maldon, Essex, England
Died	30 June 1919(1919-06-30) (aged 76) Terling Place, Witham, Essex, England
Nationality	United Kingdom
Fields	Physics
Institutions	University of Cambridge
Alma mater	University of Cambridge
Doctoral advisor	Edward John Routh
Doctoral students	J. J. Thomson George Paget Thomson Jagdish Chandra Bose
Known for	Discovery of argon Rayleigh waves Rayleigh scattering Rayleigh criterion Duplex Theory Theory of Sound Rayleigh flow
Notable awards	Nobel Prize for Physics (1904) Copley Medal (1899)
Signature

John William Strutt, 3rd Baron Rayleigh, OM (12 November 1842 – 30 June 1919) was an English physicist who, with William Ramsay, discovered the element argon, an achievement for which he earned the Nobel Prize for Physics in 1904. He also discovered the phenomenon now called Rayleigh scattering, explaining why the sky is blue, and predicted the existence of the surface waves now known as Rayleigh waves. Rayleigh's textbook, The Theory of Sound, is still referred to by acoustic engineers today.

Biography

Strutt was born in Langford Grove, Essex, and in his early years suffered from frailty and poor health. He attended Harrow School, before going on to the University of Cambridge in 1861 where he studied mathematics at Trinity College. He obtained a Bachelor of Arts degree (Senior Wrangler and 1st Smith's prize) in 1865, and a Master of Arts in 1868. He was subsequently elected to a Fellowship of Trinity. He held the post until his marriage to Evelyn Balfour, daughter of James Maitland Balfour, in 1871. He had three sons with her. In 1873, on the death of his father, John Strutt, 2nd Baron Rayleigh, he inherited the Barony of Rayleigh.

He was the second Cavendish Professor of Physics at the University of Cambridge (following James Clerk Maxwell), and held this position from 1879 to 1884. He first described dynamic soaring by seabirds in 1883, in the British journal Nature. From 1887 to 1905 he was Professor of Natural Philosophy at Cambridge.

Around the year 1900 Lord Rayleigh developed the Duplex (combination of two) Theory of human sound localization using two binaural cues, interaural time delay (ITD) and interaural level difference (ILD) (assuming a spherical head with no external pinnae). Humans perceive sound sources spatially, using the difference in the phase (time delay) of the sound and the difference in amplitude (level) between the two ears, in a similar way that stereoscopic sight provides depth perception. The theory posits that we use two primary cues for azimuth (horizontal location) as well as for a 3-dimensional bearing, although pinnae reflections are considered a main cue for vertical localisation. For example, when you hear a seagull call, you can determine roughly the location of the sound on mental x, y, and z axes.

Lord Rayleigh was elected Fellow of the Royal Society on 12 June 1873, and served as president of the Royal Society from 1905 to 1908. From time to time Lord Rayleigh participated in the House of Lords; however, he spoke up only if politics attempted to become involved in science. He died on 30 June 1919, in Witham, Essex. He was succeeded, as the 4th Lord Rayleigh, by his son Robert John Strutt, another well known physicist.

Honours and awards

Craters on Mars and the Moon are named in his honor as well as a type of surface wave known as a Rayleigh wave. The asteroid 22740 Rayleigh was named in his honour on 1 June 2007.

• Smith's Prize (1864)
• Royal Medal (1882)
• Matteucci Medal (1894)
• Member of the Royal Swedish Academy of Sciences (1897)
• Copley Medal (1899)
• Order of Merit (1902)
• Nobel Prize for Physics (1904)
• Elliott Cresson Medal (1913)
• Rumford Medal (1914 & 1920)

Bibliography

• The Theory of Sound vol. I (London : Macmillan, 1877, 1894) (alternative link: Bibliothèque Nationale de France OR (Cambridge: University Press, reissued 2011, ISBN 9781108032209)
• The Theory of Sound vol.II (London : Macmillan, 1878, 1896) (alternative link: Bibliothèque Nationale de France) OR (Cambridge: University Press, reissued 2011, ISBN 9781108032216)
• The Becquerel rays and the properties of radium (London, E. Arnold, 1904)
• Scientific papers (Vol. 1: 1869–1881) (Cambridge : University Press, 1899–1920, reissued by the publisher 2011, ISBN 9780511703966)
• Scientific papers (Vol. 2: 1881–1887) (Cambridge : University Press, 1899–1920, reissued by the publisher 2011, ISBN 9780511703973)
• Scientific papers (Vol. 3: 1887–1892) (Cambridge : University Press, 1899–1920, reissued by the publisher 2011, ISBN 9780511703980)
• Scientific papers (Vol. 4: 1892–1901) (Cambridge : University Press, 1899–1920, reissued by the publisher 2011, ISBN 9780511703997)
• Scientific papers (Vol. 5: 1902–1910) (Cambridge : University Press, 1899–1920, reissued by the publisher 2011, ISBN 9780511704000)
• Scientific papers (Vol. 6: 1911–1919) (Cambridge : University Press, 1899–1920, reissued by the publisher 2011, ISBN 9780511704017)

See also

• Rayleigh criterion
• Rayleigh fading
• Rayleigh number
• Rayleigh quotient
• Rayleigh (unit) (named after his son Robert John Strutt)
• Rayleigh–Jeans law
• Rayleigh law
• Rayleigh distribution
• Rayleigh–Taylor instability
• Plateau–Rayleigh instability
• Rayleigh Medal
• Rayleigh–Bénard convection
• Rayleigh's method of dimensional analysis
• Experiments of Rayleigh and Brace

External links

• About John William Strutt
• O'Connor, John J.; Robertson, Edmund F., "John Strutt, 3rd Baron Rayleigh", MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Rayleigh.html .

Honorary titles
Preceded by The Lord Carlingford	Lord Lieutenant of Essex 1892–1901	Succeeded by The Earl of Warwick
Academic offices
Preceded by The Duke of Devonshire	Chancellor of the University of Cambridge 1908–1919	Succeeded by Arthur Balfour
Peerage of the United Kingdom
Preceded by John Strutt	Baron Rayleigh 1873–1919	Succeeded by Robert Strutt