1-151-884 - Ann Ronan Picture Library/Heritage-Images

JJ Thomson, British physicist, at work in the Cavendish Laboratory, Cambridge. Joseph John Thomson (1856-1940) discovered the electron and was a pioneer of nuclear physics. In 1896 at Cambridge he began experiments on cathode rays, demonstrating that they were in fact particles with a negative charge and were much smaller than an atom. These particles were later renamed electrons. He was awarded the Nobel Prize for Physics in 1906 and was knighted in 1908.