Sir Joseph John Thomson was born on 18December 1856. His father was a merchant selling rare objects. Thomson joined Manchester Victoria University and completed basic technical education at 19. He went to Cambridge and joined Trinity college. He obtained degree from there and became a fellow. He carried out research. He occupied the chair at Cavendish laboratory where Lord Rayleigh was working. Rayleigh nominated Thomson to his seat and resigned. Thomson was there for 34 years and succeeded.

Thomson found that negative rays are electrical particles in the crooke’s tube. The electrical particles were called electrons. Thomson was called the father of the electron. He was awarded Nobel prize in 1906 for the discovery of electron. His discovery opened the field of subatomic particles. In 1985 he began to investigate the mysterious rays coming from Cathode called Cathode rays when electricity was passed through vaccum in a glass tube. By measuring the deflections of Cathode rays when they were passed between charged metal plates he could determine they were negatively charged could determine they were negatively charged particles now called ‘electrons’ He also discovered ISOTOPES 20 NC and 22 NC which enabled the invention of mass spectrograph.

Thomson was instrumental in building up the Cavendish Laboratory as a great experimental research school. When the first world war ended Thomson retired from the duties of the laboratory and became the head of Trinity college. Rutherford, his student chaired Cavendish Laboratory.

Thomson was instrumental in building up the Cavendish Laboratory as a great experimental research school. When the first world war ended Thomson retired from the duties of the laboratory and became the head of Trinity college. Rutherford, his student chaired Cavendish Laboratory.

Thomson had married Rose Peget. They had a son George Peget Thomson who won Nobel prize in 1937 for discovery of diffraction of electrons by crystals. Thomson was happy. He died in 1940.