John William Strutt, 3rd Baron Rayleigh

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Lord Rayleigh
John William Strutt.jpg
Born (1842-11-12)12 November 1842
Langford Grove, Maldon, Essex, England
Died 30 June 1919(1919-06-30) (aged 76)
Terling Place, Witham, Essex, England
Nationality British
Fields Physics
Institutions University of Cambridge
Alma mater University of Cambridge
Academic advisors Edward John Routh
Notable students
Known for
Notable awards

John William Strutt, 3rd Baron Rayleigh, OM, PRS (/ˈrli/; 12 November 1842 – 30 June 1919) was an English physicist who, with William Ramsay, discovered 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.


John William Strutt, of Terling Place Essex, suffered from frailty and poor health in his early years.[1] 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.[2] 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.[3] 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), 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 phase difference (IPD) and interaural level difference (ILD) (based on analysis of a spherical head with no external pinnae). The theory posits that we use two primary cues for sound lateralization, using the difference in the phases of sinusoidal components of the sound and the difference in amplitude (level) between the two ears.

The rayl unit of acoustic impedance is named after him.

As an advocate that simplicity and theory be part of the scientific method, Lord Rayleigh argued for the principle of similitude.

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.[3] He was succeeded, as the 4th Lord Rayleigh, by his son Robert John Strutt, another well-known physicist.

Honours and awards[edit]

Craters on Mars and the Moon are named in his honour 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.[4] The rayl, a unit of acoustic impedance, is named for him.


See also[edit]


  1. ^ "Sketch of Lord Rayleigh". The Popular Science Monthly (Bonnier Corporation) 25 (46): 840 ff. October 1884. 
  2. ^ "Strutt, the Hon. John William (STRT861JW)". A Cambridge Alumni Database. University of Cambridge. 
  3. ^ a b "Lord Rayleigh: The Nobel Prize in Physics 1904". The Nobel Foundation. 1904. Retrieved 2010-05-05. 
  4. ^ JPL (2008). "JPL Small-Body Database Browser: 22740 Rayleigh (1998 SX146)". NASA. Retrieved 2008-07-23. 

External links[edit]

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