John William Strutt, 3rd Baron Rayleigh

John William Strutt, 3rd Baron Rayleigh (1842 to 1919), known as Lord Rayleigh, was a British physicist and hereditary peer who received the Nobel Prize in Physics in 1904 for his discovery of argon. In 1871 he published the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, now called Rayleigh scattering, which explains why the sky is blue. He also described Rayleigh waves in solids, contributed widely to fluid dynamics and wrote The Theory of Sound (1877). He was Cavendish Professor of Physics at the University of Cambridge from 1879, President of the Royal Society from 1905 to 1908 and Chancellor of the University of Cambridge from 1908 until his death.