Ernest Rutherford
1871 – 1937 · New Zealand
Known for: New Zealand physicist who discovered the atomic nucleus and founded nuclear physics
“He looked into the atom and found its nucleus.”
Biography
Ernest Rutherford was born on 30 August 1871 at Brightwater in the north of New Zealand's South Island, the fourth of twelve children of James Rutherford, a farmer and mechanic from Perth in Scotland, and Martha Thompson, a schoolteacher from Hornchurch in England. The family moved to Foxhill and then to Havelock in the Marlborough Sounds, where his father ran a flax mill. He won a scholarship to Nelson College at his second attempt in 1887, was head boy there in 1889, and went on to Canterbury College, taking degrees in mathematics, physical science, chemistry and geology between 1892 and 1894. He built a new form of radio receiver, and in 1895 an 1851 Exhibition research fellowship carried him to the Cavendish Laboratory at Cambridge, to work under J. J. Thomson.
Rutherford turned to the new phenomenon of radioactivity, distinguishing two kinds of radiation which he named alpha and beta in 1899. At McGill University in Montreal, where he took the Macdonald Chair of Physics in 1898, he and the chemist Frederick Soddy showed that radioactive elements transform themselves into other elements, and found that any sample of a given substance always took the same time for half of it to decay, a quantity Rutherford called the half-life. He identified the radioactive gas later known as radon and, with Thomas Royds, proved that alpha particles are the nuclei of helium atoms; the Nobel Prize in Chemistry followed in 1908. At Manchester, in 1911, he read the strange scattering of alpha particles by a thin gold foil, observed by Hans Geiger and Ernest Marsden, as evidence that almost the whole charge and mass of an atom sits in a minute central nucleus.
He invited Niels Bohr to his laboratory in 1912, and Bohr's model of the atom grew out of that work. In 1917 he bombarded nitrogen with alpha particles and brought about the first artificially induced nuclear reaction, identifying the particle it released and later naming it the proton. As director of the Cavendish Laboratory from 1919 he presided over the discovery of the neutron by James Chadwick in 1932 and, in the same year, over the first splitting of the nucleus by John Cockcroft and Ernest Walton. He was raised to the peerage as Baron Rutherford of Nelson, and when he died on 19 October 1937 he was buried in Westminster Abbey near Newton and Darwin. Element 104 was named rutherfordium in 1997, and his portrait has appeared on the New Zealand hundred dollar note since 1999.