John William Strutt, 3rd Baron Rayleigh (12 November 1842 – 30 June 1919) was an English physicist who (with William Ramsay) discovered the element argon, an achievement that earned him the Nobel Prize for Physics in 1904. He also discovered the phenomenon now called Rayleigh scattering and predicted the existence of the surface waves now known as Rayleigh waves.
Strutt was born in Langford Grove, Essex and in his early years suffered frailty and poor health.
Read John William Strutt's Nobel Prize lecture, free from Nobelprize.org.
He went to Harrow School and began studying mathematics at Trinity College, University of Cambridge, in 1861. In 1865, he obtained his BA (Senior Wrangler and 1st Smith's prize) and MA 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 his father, John Strutt, 2nd Baron Rayleigh died, and he inherited the Barony of Rayleigh.
He was the second Cavendish Professor of Physics at the University of Cambridge, following James Clerk Maxwell in this position from 1879 to 1884. He first described dynamic soaring by seabirds in 1883 in the British journal Nature.
Approximately 1900 Lord Rayleigh developed the Duplex (combination of two) Theory (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 objects 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. Also called two primary cues for azimuth (horizontal location) but possibly its two primary cues for a 3 dimensional bearing. For example when you hear a seagull call out you can determine roughly x y and z location of the sound. Although Pinnae reflections are considered a main cue for vertical localisation.
Lord Rayleigh was elected to Fellow of the Royal Society on June 12, 1873 and was elected president of the Royal Society between 1905 and 1908.
Lord Rayleigh died on June 30, 1919 in Witham, Essex.
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.