Also at the Cavendish, John Cockcroft and Ernest Walton built the first machine – using plasticine to seal its joints the Cavendish did not encourage extravagance – to disintegrate an atomic nucleus with accelerated particles. The year 1932 was a scientific annus mirabilis. Thus, it was an ideal tool for the investigation of atoms. The neutron contained no charge – hence its name – and, if used to bombard elements, it could penetrate atomic nuclei without being deflected. One of his former pupils, James Chadwick, discovered the sub-atomic particle at Cambridge University’s Cavendish Laboratory in 1932. Rutherford already suspected the presence of another particle within the nucleus: the neutron. He became the first person to chip a piece off an atomic nucleus, in the process identifying a sub-atomic particle – the positively charged proton (his mentor JJ Thomson had discovered electrons some years before). (Photo by Ann Ronan Pictures/Print Collector/Getty Images) As well as the 80,000 who died in the blast, 60,000 had succumbed to radiation sickness and related diseases by December 1945. Survivors of the atomic bombing lie in hospital beds in Hiroshima, suffering from the effects of radiation.
