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J.J. Thomson

Sir Joseph John Thomson, more commonly known as J. J. Thomson, was an English physicist

who stormed the world of nuclear physics with his 1897 discovery of the electron, as well as

isotopes. He is also credited with the invention of the mass spectrometer. He received the Nobel

Prize for Physics in 1906 and was knighted two years later in 1908.

Early Life and Education:

Born in 1856 in Cheetham Hill near Manchester, England, J. J. Thomson was the son of a

Scottish bookseller. He won a scholarship to Trinity College, Cambridge in 1876. He received

his BA in 1880 in mathematics, and MA in 1883.

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Contributions and Achievements:

J. J. Thomson was appointed a Fellow of the Royal Society 1865. He was a successor to Lord

Rayleigh as Cavendish Professor of Experimental Physics. His favorite student Ernst Rutherford

later succeeded him in 1919. The early theoretical work of Thomson broadened the

electromagnetic theories of James Clerk Maxwell’s, which revolutionized the study of gaseous

conductors of electricity, as well as the nature of cathode rays.

Inspired by Wilhelm Röntgen’s 1895 discovery of X-rays, Thomson demonstrated that cathode

rays were actually some speedily moving particles. After measuring their speed and specific

charge, he concluded that these “corpuscles” (electrons) were about 2000 times smaller in mass

as compared to the hydrogen ion, the lightest-known atomic particle. The discovery, made public

during Thomson’s 1897 lecture to the Royal Institution, was labeled as the most influential

breakthrough in the history of physics since Sir Isaac Newton.

Thomson also researched on the nature of positive rays in 1911, which significantly helped in the

discovery of Isotopes. He proved that isotopes could be broke by deflecting positive rays in

electric and magnetic fields, which was later named mass spectrometry.

J. J. Thomson was awarded the Nobel Prize for physics in 1906. He was knighted in 1908. He

published his autobiography “Recollections and Reflections” in 1936. Thomson is widely

considered to be one of the greatest scientists ever, and the most influential pioneer of nuclear

physics.

Later Life and Death:

J. J. Thomson was made the Master of Trinity College, Cambridge in 1918, where he remained

until his death. He died on August 30, 1940. He was 83 years old. Thomson was buried close to

Isaac Newton in Westminster Abbey.