The Lord Rutherford of Nelson
OM FRS
Lord Rutherford of Nelson
Born
30 August 1871
Brightwater, New Zealand
Died
19 October 1937 (aged 66)
Cambridge, England, UK
Residence
New Zealand, UK, Canada
Citizenship
New Zealand, United Kingdom
Fields
Physics and Chemistry
Institutions
McGill University
University of Manchester
Alma mater
University of Canterbury
University of Cambridge
Academic advisors
Alexander Bickerton
J. J. Thomson
Doctoral students
Nazir Ahmed
Norman Alexander
Edward Victor Appleton
Robert William Boyle
Rafi Muhammad Chaudhry
Alexander MacAulay
Cecil Powell
Henry DeWolf Smyth
Ernest Walton
C. E. Wynn-Williams
Yulii Borisovich Khariton
Other notable students Edward Andrade
Edward Victor Appleton
Patrick Blackett
Niels Bohr
Bertram Boltwood
Harriet Brooks
Teddy Bullard
James Chadwick
John Cockcroft
Charles Galton Darwin
Charles Drummond Ellis
Kazimierz Fajans
Hans Geiger
Otto Hahn
Douglas Hartree
Pyotr Kapitsa
George Laurence
Iven Mackay
Ernest Marsden
Mark Oliphant
Thomas Royds
Frederick Soddy
Known for
Father of nuclear physics
Rutherford model
Rutherford scattering
Rutherford backscattering spectroscopy
Discovery of proton
Rutherford (unit)
Coining the term 'artificial disintegration'
Influenced
Henry Moseley
Hans Geiger
Albert Beaumont Wood
Notable awards
Rumford Medal (1905)
Nobel Prize in Chemistry (1908)
Elliott Cresson Medal (1910)
Matteucci Medal (1913)
Copley Medal (1922)
Franklin Medal (1924)
Signature
Early life and education
Ernest Rutherford was the son of James Rutherford, a farmer, and his wife Martha Thompson, originally
from Hornchurch, Essex, England. James had emigrated to New Zealand from Perth, Scotland, "to raise
a little flax and a lot of children". Ernest was born at Spring Grove (now Brightwater), near Nelson, New
Zealand. His first name was mistakenly spelled 'Earnest' when his birth was registered. [11]
He studied at Havelock School and then Nelson College and won a scholarshipto study at Canterbury
College, University of New Zealand where he participated in the debating society and played rugby. After
gaining his BA, MA and BSc, and doing two years of research during which he invented a new form of
radio receiver, in 1895 Rutherford was awarded an "1851 Exhibition Scholarship" to travel to England for
postgraduate study at the Cavendish Laboratory, University of Cambridge. He was among the first of the
'aliens' (those without a Cambridge degree) allowed to do research at the university, under the inspiring
leadership of J. J. Thomson, and the newcomers aroused jealousies from the more conservative
members of the Cavendish fraternity. With Thomson's encouragement, he managed to detect radio
waves at half a mile and briefly held the world record for the distance over which electromagnetic waves
could be detected, though when he presented his results at the British Associationmeeting in 1896, he
discovered he had been outdone by another lecturer, by the name of Marconi.
In 1898 Thomson offered Rutherford the chance of a post at McGill University in Montreal, Canada. He
was to replace Hugh Longbourne Callendar who held the chair of Macdonald Professor of physics and
was coming to Cambridge Rutherford was accepted, which meant that in 1900 he could marry Mary
Georgina Newton (1876–1945) to whom he had become engaged before leaving New Zealand; they had
one daughter, Eileen Mary (1901–1930), who married Ralph Fowler. In 1900 he gained a DSc from the
University of New Zealand. In 1907 Rutherford returned to Britain to take the chair of physics at
the University of Manchester.
Later years and honours[edit]
He was knighted in 1914. During World War I, he worked on the practical problems of submarine
detection. In 1916 he was awarded the Hector Memorial Medal. In 1919 he returned to the Cavendish
succeeding J. J. Thomson as the Cavendish professor and Director. Under him, Nobel Prizes were
awarded to James Chadwick for discovering the neutron (in 1932), John Cockcroft and Ernest Walton for
an experiment which was to be known as splitting the atom using a particle accelerator, and Edward
Appleton for demonstrating the existence of the ionosphere. Between 1925 and 1930 he served
as President of the Royal Society, and later as president of the Academic Assistance Council which
helped almost 1,000 university refugees from Germany. He was admitted to the Order of Meritin 1925
and raised to the peerage as Baron Rutherford of Nelson, in 1931, a title that became extinct upon his
unexpected death in 1937.
For some time beforehand, Rutherford had a small hernia, which he had neglected to have fixed, and it
became strangulated, causing him to be violently ill. Despite an emergency operation in London, he died
four days afterwards of what physicians termed "intestinal paralysis", at Cambridge. After cremation
at Golders Green Crematorium, he was given the high honour of burial in Westminster Abbey, near Isaac
Newton and other illustrious British scientists
Rutherford and the Gold Foil Experiment
Top: Expected results: alpha particles passing through the plum pudding model of the atom undisturbed.
Bottom: Observed results: a small portion of the particles were deflected, indicating a small, concentrated charge. Note that
the image is not to scale; in reality the nucleus is vastly smaller than the electron shell.
Rutherford remains the only science Nobel Prize winner to have performed his most famous
workafter receiving the prize. Along with Hans Geiger and Ernest Marsden in 1909, he carried out
the Geiger–Marsden experiment, which demonstrated the nuclear nature of atoms. Rutherford was
inspired to ask Geiger and Marsden in this experiment to look for alpha particles with very high deflection
angles, of a type not expected from any theory of matter at that time. Such deflections, though rare, were
found, and proved to be a smooth but high-order function of the deflection angle. It was Rutherford's
interpretation of this data that led him to formulate the Rutherford model of the atom in 1911 – that a very
small charged nucleus, containing much of the atom's mass, was orbited by low-mass electrons.
Before leaving Manchester in 1919 to take over the Cavendish laboratory in Cambridge, Rutherford
became, in 1919, the first person to deliberately transmute one element into another In this experiment,
he had discovered peculiar radiations when alphas were projected into air, and narrowed the effect down
to the nitrogen, not the oxygen in the air. Using pure nitrogen, Rutherford used alpha radiation to
convert nitrogen into oxygen through the nuclear reaction 14N + α → 17O + proton. The proton was not
then known. In the products of this reaction Rutherford simply identified hydrogen nuclei, by their
similarity to the particle radiation from earlier experiments in which he had bombarded hydrogen gas with
alpha particles to knock hydrogen nuclei out of hydrogen atoms. This result showed Rutherford that
hydrogen nuclei were a part of nitrogen nuclei (and by inference, probably other nuclei as well). Such a
construction had been suspected for many years on the basis of atomic weights which were whole
numbers of that of hydrogen; see Prout's hypothesis. Hydrogen was known to be the lightest element,
and its nuclei presumably the lightest nuclei. Now, because of all these considerations, Rutherford
decided that a hydrogen nucleus was possibly a fundamental building block of all nuclei, and also
possibly a new fundamental particle as well, since nothing was known from the nucleus that was lighter.
Thus, Rutherford postulated hydrogen nuclei to be a new particle in 1920, which he dubbed the proton.
In 1921, while working with Niels Bohr (who postulated that electrons moved in specific orbits), Rutherford
theorized about the existence of neutrons, (which he had christened in his 1920 Bakerian Lecture), which
could somehow compensate for the repelling effect of the positive charges of protons by causing an
attractive nuclear force and thus keep the nuclei from flying apart from the repulsion between protons.
The only alternative to neutrons was the existence of "nuclear electrons" which would counteract some of
the proton charges in the nucleus, since by then it was known that nuclei had about twice the mass that
could be accounted for if they were simply assembled from hydrogen nuclei (protons). But how these
nuclear electrons could be trapped in the nucleus, was a mystery.
Rutherford's theory of neutrons was proved in 1932 by his associate James Chadwick, who recognized
neutrons immediately when they were produced by other scientists and later himself, in bombarding
beryllium with alpha particles. In 1935, Chadwick was awarded the Nobel Prize in Physics for this
discovery.