Bragg, Sir William Henry (1862-1942), a British physicist, shared the 1915 Nobel Prize in physics with his son Sir William Lawrence Bragg. The two men pioneered the use of X rays to study the structure of molecules. They arranged the molecules into crystals and bombarded the crystals with X rays. By analyzing how the X rays diffract (spread out) as they pass through the crystal, the two men determined the arrangement of atoms within the molecules. The technique, later called X-ray crystallography, became a fundamental part of chemistry and molecular biology.
William Henry Bragg became an expert in radioactivity soon after its discovery. He believed that the newly discovered X rays were streams of particles. In 1912, he and his son tried to use this theory to interpret X-ray experiments conducted by the German physicist Max von Laue. The theory was discarded, but their work led to the development of X-ray crystallography.
During World War I (1914-1918), Bragg helped organize scientific research for the British Navy. His work on detecting submarines led to the development of sonar, the use of sound waves to locate underwater objects.
Bragg was born at Westward, England, near Carlisle, on July 2, 1862. He studied at Cambridge University. He became a professor at the University of Adelaide in Australia in 1885, the University of Leeds in England in 1909, and University College London in 1915. He was knighted in 1920. From 1923 until his death, he directed the Royal Institution of Great Britain, an organization devoted to science education. There, he became known for his lectures to children and the public. Bragg died on March 12, 1942.
