Rutherford’s path to the Nobel Prize
December 2008 marks 100 years since Canterbury alumnus Ernest Rutherford received his Nobel Prize, a first for a person educated in New Zealand. Dr John Campbell looks back at the early life of one of New Zealand’s most famous sons.
One of the most illustrious scientists of all time, Ernest Rutherford is to the atom what Darwin is to evolution, Newton to mechanics, Faraday to electricity and Einstein to relativity.
His pathway from rural child to immortality is a fascinating one.
Rutherford nearly didn’t make it to secondary school. In the late 19th century, education in New Zealand was compulsory to age 12 and free to the age of 14. Secondary schools were then private schools and expensive to attend.
The Rutherford family of Havelock could not afford to send young Ern to Nelson College. His only chance was the one scholarship available to Marlborough pupils. On his second attempt, he gained the scholarship but only because Edward Pasley, eight months his junior, crashed in English. Pasley, who went on to become a travelling salesman, had beaten Rutherford in geography and history and they had tied in maths. Had Pasley not crashed in English, Rutherford may well have accepted the offer of a cadetship in the civil service having been placed 15th of the 202 candidates for the 1886 Junior Civil Service Examination.
Fifteen-year-old Rutherford entered Nelson College in 1887, at the fifth form level as befitting his age and schooling. He regularly won prizes — and hence more money for fees and boarding — in modern languages and literature.
In 1888 he matriculated to the University of New Zealand, but was not placed high enough in the junior scholarship examination list to be awarded funding. Unable to afford to go without a scholarship, Rutherford stayed on at Nelson College for a further year and was named dux of the school.
In 1889, on his second attempt, he won one of the 10 Junior National Scholarships to the University of New Zealand. At Canterbury College he came under the influence of the professor of chemistry and practical physics, Alexander Bickerton, who taught him to think and inspired him into research.
Rutherford was a good student but only on a par with others. Willie Marris, who beat Rutherford in mathematics, was a classics scholar from Wanganui who left after his BA degree to go to England to cram for the Indian Civil Service exams. He rose to be Sir William Marris, Governor of Assam. Apirana Ngata, the first Mäori to attend Canterbury College, studied law. He later became Sir Apirana Ngata, politician, and the head on the New Zealand $50 banknote. Jack Erskine, an excellent mathematician from Southland, followed Rutherford by a year and was to carry on research started by Rutherford.
Erskine went into electrical engineering before making a fortune on the stock market. Today’s Erskine Fellowships offered by UC in the faculties of science, engineering and commerce, stem from Erskine’s generosity and frugal life.
Rutherford threw himself into the life of an undergraduate. He started in the college’s third rugby team, rising through age and attrition to its first team which was generally thrashed. He joined the science society in its formation year during which the word “evolution” was in the title of a third of the topics discussed. At the Dialectic Society he argued “That the influence of the modern newspaper press is excessive and dangerous” and “That the average value of environment as a factor in the formation of character is greater than that of heredity”. Rutherford helped Erskine pen one of the anonymous songs sung irreverently at the annual capping ceremony, highlighting the clash between arts and sciences.
For the BA degree, students studied equally in six subjects, four being examined after the second year and the other two in the final (third) year. Mathematics and Latin were compulsory. For the other four subjects, Rutherford chose applied mathematics, French, English and physics (BA students were restricted to only two science subjects).
Rutherford won the one senior scholarship in mathematics available nationwide that allowed for another year (1893) at the University of New Zealand, during which he took honours (Master of Arts) in mathematics and experimental science. By then he was boarding with a widow, Mary Newton, whose husband had drunk himself to death. At the time the Woman’s Christian Temperance Union was striving for universal suffrage as it believed the only way women would have control over the demon booze was if they could vote. Newton was the right-hand woman of the movement’s leader, Kate Sheppard, whose image today graces the New Zealand $10 banknote. In 1893, New Zealand became the first country in the world to grant women the vote. It was also the year Rutherford was old enough to be listed on the electoral roll. He had an insider’s view of this momentous occasion.
Rutherford’s honours in physical science was entirely by exam but the regulations required him to go into the exam room with a note from his professor saying that the candidate had carried out original research.
Bickerton had developed a theory of astrophysics (the partial impact theory) which he thought could explain all astronomical observations such as nova and, indeed, life itself. Bickerton suggested Rutherford study the electrical synthesis of the nitro-compounds of hydrogen, carbon and oxygen, but he declined because he didn’t have a chemical background. (In the 1950s Stanley Miller and Harold Urey attained world fame in carrying out such experiments, to produce the building blocks of life.)
Instead Rutherford chose to extend an undergraduate experiment measuring the magnetism of iron to study whether the results also held for rapidly-cycling magnetizing fields. Rutherford was inspired by Nikola Tesla who had come to world notice in August of 1893 when he publicly demonstrated transmitting electrical power without wires. (A discharge tube glowed when held near his high-frequency, high-voltage transformer.) Alternating currents were the high technology of the day.
Rutherford made a mechanical device which could switch on an electric current then, within 100,000th of a second, could switch on a circuit to measure the effect of the current thus far. The brilliance of Rutherford as a scientist was evident from his first year of research, during which he was mostly self-taught, as demonstrated by the skill and thought that went into the construction of his timing device.
Employment now loomed; but where? There were few jobs for physical scientists in New Zealand, apart from becoming a government analyst in one of the main cities to keep miners and industry honest. Rutherford missed out on permanent employment as a schoolteacher on several occasions but was employed at Christchurch Boys’ High for a short time as a relieving teacher. The only surviving account of this experience, that of a boy in a junior mathematics class, was not flattering. Rutherford couldn’t control a class and was a bit advanced for them.
His only chance to progress in science was to continue research with an Exhibition of 1851 science scholarship in mind. In 1894, Rutherford returned to Canterbury College and enrolled for a BSc. This relatively new degree allowed students to avoid Latin. With two science subjects already under his belt from his BA degree, Rutherford’s choice for the two extra subjects needed for a BSc was chemistry and geology.
Rutherford extended his magnetic research to even higher frequencies, using a damped Hertzian oscillator to reach even higher oscillating current rates. He slowly dissolved the surface of his iron needle to show that at high frequencies only a thin surface skin was magnetised and the magnetism direction reversed lower in this layer. During this work he invented a simple device for detecting the passage of a current pulse of very short duration, down to about one two-hundred-thousandths of a second. This involved placing a steel needle in a small coil in the circuit and using a sensitive magnetometer to detect that the magnetism of the needle had changed.
There were two applicants for the nomination of the Exhibition of 1851 science scholarship, which was awarded to Rutherford after the successful nominee withdrew. This allowed Rutherford to travel anywhere in the world to do research in a field important to the nation’s industrial interests. So in 1895, a 23-year-old Rutherford left New Zealand’s shores holding three degrees from the University of New Zealand. Already he had a reputation as an outstanding researcher and innovator working at the forefront of electrical technology.
Rutherford elected to study with Professor J J Thomson at Cambridge University’s Cavendish Laboratory and became the University’s first non-Cambridge research student. Within five months, Rutherford held the world record for the distance over which a wireless electric-wave had been detected — half a mile. He had been encouraged in this by Sir Robert Ball, the director of the Cambridge Observatory and the scientific adviser to the Irish Light Association, who advised Rutherford that if he could get the distance to a reasonable one he would solve the terrible problem of how a ship could detect a lighthouse during fog.
Rutherford wrote to his girlfriend back in New Zealand that fame and fortune awaited. Thomson sounded out financiers who concluded that an impossibly large investment would be needed to commercialise wireless telegraphy. Fast communication was already in wide use through telegraphy and undersea cables.
Realising how good Rutherford was, Thomson invited him to join in his own research projects.
From early 1896 Rutherford helped Thomson with experiments into why putting an electrical discharge through a gas turned a good electrical insulator into a good electrical conductor.
In 1897 Thomson announced the discovery of the electron, the first object smaller than an atom. Rutherford was an immediate convert to sub-atomic particles and this became his life’s work for which he has achieved enduring fame.
For these experiments, Rutherford initially used ultraviolet light to ionise the gases he was studying. But two accidental discoveries were announced that changed physics, and Rutherford’s research field, forever. Wilhelm Conrad Roentgen in Germany accidentally discovered X-rays and Henri Becquerel in France accidentally discovered radioactivity. X-rays went into immediate service worldwide in medical physics. Radioactivity was a lesser curiosity.
Rutherford used both to ionise his gases but quickly changed to trying to understand the peculiar nature of radioactivity. Very quickly he showed that ionising rays from radioactive materials seemed to be of two sorts. One, which he called alpha rays, was highly ionizing and easily stopped, whereas the other, which he called beta rays, wasn’t as ionizing and had more penetration.
But his time at Cambridge had come to an end. His scholarship had already been extended for a third year and hopes of a fellowship were dashed by stringent rules applying to non-Cambridge graduates.
In 1889 Rutherford was appointed to lead physics research at McGill University in Canada in order, as he was told, “to knock the shine off the Yankees”. And lead he did. He quickly found that radioactive thorium gave off a radioactive emanation. He had discovered radon. This put him on the track to discover that radioactivity was the spontaneous disintegration of some heavy atoms into slightly lighter ones, with the emission of rays/particles of enormous energy. He was the first to produce the growth and decay curves for radioactivity.
Rutherford had had to carry out his own chemical separations until he was joined by a specialist chemist, Frederick Soddy, after April 1901. They worked out several of the radioactive decay chains and, initially using the amount of helium gas in a mineral containing radioactive elements, Rutherford used these decay curves to date the age of minerals and the Earth. Later, when it was realised that the final decay product in the chain that had started with uranium was stable lead, he used the uranium/lead ratios to date minerals.
Rutherford left McGill for Manchester University in 1907 but not before being nominated for a Nobel Prize, which was awarded in 1908 — in chemistry. As Rutherford told his mates it was the quickest transformation (physicist to chemist) that he had met. The citation was “for his investigations into the disintegration of the elements, and the chemistry of radioactive substances”.
Rutherford was on track to the 1937 eulogy awarded to him by the New York Times. “It is given to but few men to achieve immortality, still less to achieve Olympian rank, during their own lifetime. Lord Rutherford achieved both. In a generation that witnessed one of the greatest revolutions in the entire history of science he was universally acknowledged as the leading explorer of the vast infinitely complex universe within the atom, a universe that he was first to penetrate.”
- Dr John Campbell is author of "Rutherford Scientist Supreme" and www.rutherford.org.nz.