Sir William Henry Bragg's Birth Anniversary

 

William Henry Bragg, born on 2 July 1904, in Wigton, Cumberland, England, was a British physicist. Educated at Trinity College, Cambridge, Bragg spent 23 years teaching at the University of Adelaide in Australia, before returning to the University of Leeds in 1909.  There, working with his son William Lawrence, he invented the X-ray spectrometer in 1912, which allowed them to measure the wavelengths of X-rays. X-rays had only been discovered in 1895, and scientists were not entirely sure that they were electromagnetic waves like light and radio waves. The Braggs showed that they are, and that if you bounce X-rays off solid crystals at very slight angles, then the waves are reflected at different angles, depending on their wavelength, which one could now measure. 

The pioneer British scientist in solid-state physics was a joint winner (with his son Sir Lawrence Bragg) of the Nobel Prize for Physics in 1915 for his research on the determination of crystal structures. The Braggs remain the only father-son Nobel Laureates.  He was knighted in 1920.