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  • 8/29/2004

Ernest Rutherford

(August 30th 1871_ October 19 1937)

Ernest Rutherford is one of the most illustrious scientists of all time.

He 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.

Ernest Rutherford was born at Spring Grove in rural Nelson onAugust 30th 1871. At age ten at Foxhill School Ernest received his first science book. Amongst the many suggested experiments in it one, on using the speed of sound to determine the distance to firing cannon, gave him the knowledge to surprise his family by estimating the distance to a lighting flash. Perhaps it was also this book which inspired him to make a minature cannon out of a hat peg, a marble and blasting powder. The cannon exploded, luckily without causing injury.

In 1887 Ernest, on his second attempt, won a Scholarship to Nelson College, until that time the only scholarship available to assist a Marlborough boy to attend secondary school.

For the next three years Ernest boarded at Nelson College. In 1889 he was head boy, played in the rugby team and, once again on his second attempt, won one of the ten scholarships available nationally to assist attendance at a college of theUniversity of New Zealand.

From 1890 to 1894 Ern attendedCanterbury College in Christchurch. In 1892 he passed BA in Pure Mathematics and Latin (both compulsory), Applied Mathematics, English, French and Physics.

His mathematical ability won him the one Senior Scholarship in Mathematics available inNew Zealand. This allowed him to return for a further (honours or Masters) year during which he took both mathematics and physics. For the latter Ern was influenced by Alexander Bickerton, a liberal freethinker. The physics course required an original investigation so Ern elected to extend an undergraduate experiment in order to determine if iron was magnetic at very high frequencies of magnetising current. In this he had been inspired byNikola Tesla's use of his high frequency Tesla coil to transmit power without wires. Ern developed two devices; a simple mechanism for switching two electrical circuits with a time interval between them which could be adjusted to be as short as a hundred thousandth of a second, and a magnetic detector of very fast current pulses.

In 1893 Ern obtained a Master of Arts degree with double First Class Honours, in Mathematics and Mathematical Physics and in Physical Science (Electricity and Magnetism).

Having failed for the third time to obtain a permanent job as a school-teacher, and having briefly considered going into medicine, Ern had few other options for a career. He seemed to be limited to tutoring, to help support himself whilst carrying out more research in electrical science. The Royal Commissioners for the Exhibition of 1851 had just initiated scholarships to allow graduates of universities in theBritish Empire to go anywhere in the world and work on research of importance to their home country's industries. Every second year one scholarship was available for a graduate of the University of New Zealand.

Thus it was that in 1894 Ern returned toCanterbury College where he took geology and chemistry for a BSc degree. For the research work required of a candidate, Ern extended his researches of the previous year to even higher frequencies using the damped oscillatory current from discharging a Leyden-jar (an electrical capacitor) or a Hertzian oscillator. He showed that a steel needle surrounded by a wire loop in the discharge circuit was indeed magnetised for frequencies as high as 500 million per second. By slowly dissolving the needle in acid he showed that only a very thin surface layer of the needle was magnetised.

Two candidates submitted work for the scholarship allocated toNew Zealand. The University's examiners inEngland recommended that James Maclaurin ofAuckland University College be nominated. Maclaurin could not accept the terms of the scholarship so the University therefore nominated Ern, the only other candidate, who was duly awarded it.

Ernest Rutherford left New Zealand in 1895 as a highly skilled 23-year-old who held three degrees from the University of New Zealand and had a reputation as an outstanding researcher and innovator working at the forefront of electrical technology. His brilliance at experimental research was already established.

He elected to work with Professor J.J. Thomson ofCambridgeUniversity's Cavendish Laboratory and wasCambridge University's first non-Cambridge-graduate research student. Rutherford adapted his detector of very fast transient currents for use as a frequency meter and used it to measure the dielectric properties of electrical insulators. To compare its sensitivity as a detector of electromagnetic waves against that of the standard detector of the time, the coherer, he mounted his detector in the receiving circuit of a Hertzian oscillator/receiver unit and found, as had others before him, that he could detect electromagnetic waves over a few metres even when there was a brick wall between the two circuits.

Encouraged by Sir Robert Ball, who wished to solve the difficult problem that a ship could not detect a lighthouse in fog, and sensing fame and fortune, Rutherford increased the sensitivity of his apparatus until, in February of 1896, he could detect electromagnetic waves over a distance of several hundred metres, a then world record.

J.J. Thomson, who was about to discover the first object smaller than an atom (the electron), quickly realized that Rutherford was a researcher of exceptional ability. Thomson invited him to join in a study of the electrical conduction of gases. Wireless telegraphy was thus left for Guglielmo Marconi to develop and commercialize.

Rutherford developed several ingenious techniques to study the mechanism whereby normally insulating gases become electrical conductors when a high voltage is applied across them. When X-rays were discovered a few months later he used them to initiate electrical conduction in gases. He repeated this with rays from radioactive atoms when they were discovered in 1896. His interest soon switched to understanding radioactivity itself, an interest which became his life's work but his contribution to the earlier fields should not be forgotten.

In 1898Rutherford discovered that two quite separate types of emissions came from radioactive atoms and he named them alpha and beta rays. Beta rays were soon shown to be high speed electrons.

Barred in the near term from advancement at Cambridge, Rutherford in 1898 accepted a professorship atMcGill University in Montreal, Canada. The laboratories at McGill were very well equipped.

Rutherford returned to New Zealand in 1900 to marry Mary Georgina Newton, the daughter of his landlady in Christchurch. They were to have one child, Eileen.

At McGillRutherford promptly discovered radon, a chemically unreactive but radioactive gas. In this he was assisted by his first research student, Harriet Brookes. Rutherford, with the later help of a young chemist,Frederick Soddy, unravelled the mysteries of radioactivity, showing that some heavy atoms spontaneously decay into slightly lighter atoms. This was the work which first brought him to world attention. He was elected a Fellow of the Royal Society of Canada in 1900 and of London in 1903. His first book Radioactivity was published in 1904. In 1908 he was awarded the Nobel Prize in Chemistry 'for his investigations into the disintegration of the elements and the chemistry of radioactive substances.' As a bemused Ern often told friends, the fastest transformation he knew of was his transformation from a physicist to a chemist.

On realizing that lead was the final decay product of uranium,Rutherford proposed that a measure of their relative proportions and the rate of decay of uranium atoms would allow minerals to be dated and, subsequently, this technique placed a lower limit on the age of the formation of the Earth. Radioactive dating of geological samples underpins modern geology. Throughout his time inCanada Rutherford was regularly head-hunted by American universities and institutions, for example Yale and the Smithsonian Institute. The main result of these approaches was that McGill kept upping his salary.Rutherford always had a shift in mind, but only toBritain in order to be nearer the main centers of science, and to have access to more, and better, research students.

Professor Schuster of Manchester University inherited a large fortune so offered to step down from his chair if Rutherford would accept the position. Transferring there in 1907 he showed convincingly what he had long suspected, namely that the alpha particle was a helium atom stripped of its electrons. He and an assistant, Hans Geiger, developed the electrical method of tirelessly detecting single particles emitted by radioactive atoms, the Rutherford-Geiger detector. With this he could determine important physical constants such as Avogadro's number, the number of atoms or molecules in one gramme-mole of material.

In 1911, Rutherford deduced from these results that almost all of the mass of an atom, an object so small that it would take over five million of them side-by-side to cross a full stop on this page, is concentrated in a nucleus a thousand times smaller than the atom itself. (If the orbital electrons in our atoms were compressed into the nucleus we would occupy the space of a small grain of sand.) The nuclear model of the atom had been born. This second great discovery gave him enduring fame.

A young Dane, Neils Bohr, was attracted to work withRutherford after having seen him in jovial mood whilst being feted at a Cavendish Laboratory dinner. Bohr placed the electrons in stable formation around the atomic nucleus. The Rutherford-Bohr atom features in chemistry and physics books used world-wide and Rutherford scattering is still used today to probe sub-nuclear particles and the structure of micro-electronic devices.

In 1919Rutherford became the Director of Cambridge University's Cavendish Laboratory. His support helped the establishment ofNew Zealand's Department of Scientific and Industrial Research in 1926.

He spoke only twice in the House of Lords, on both occasions in support of industrial research.

1932 was a vintage year for Rutherford and the Cavendish Laboratory.James Chadwick discovered the neutron. A decade earlier Rutherford had predicted it must exist and in the interim had often mentioned to Chadwick what properties it must have.

In that same yearJohn Cockcroft and Ernest Walton finally split the atom by entirely artificial means using protons, the nuclei of hydrogen atoms, which had been accelerated to very high speeds in a high voltage accelerator. The age of big science had begun underRutherford's guidance.

For yearsRutherford had assumed that to penetrate the nucleus of an atom one would need particles accelerated through a few million volts to match the energy with which particles were ejected from radioactive atoms. Hence for years he had cajoled British industry to push development of high voltage sources. The breakthrough though came from George Gamow's application of quantum mechanics to show that lower energies would be more efficient at penetrating the atomic nucleus.

After Cockcroft and Walton's success,Rutherford hadMark Oliphant build a lower voltage accelerator but with a much improved particle flux. Following the gift of heavy hydrogen (dueterium) from Gilbert Lewis of Berkeley, they bombarded dueterium with deuterium and discovered tritium (H3 the third isotope of hydrogen) and the light isotope of helium (He3).

Rutherford served well his science, his laboratory, his university and his adopted country. He campaigned forCambridgeUniversity to grant women the same privileges as men.

Rutherford was one of the first to determine that the energy involved in the radioactive decay of an atom was millions of times that of a chemical bond and he was the first to be convinced that the energy was internal to all atoms. In 1916, during the dark days of World War I, Rutherford stated that there was then no way that the energy of the atom could be extracted efficiently and he personally hoped that methods would not be discovered until man was living at peace with his neighbours.

When Hitler rose to power inGermany in 1933 and commenced his non-Aryan policy, Lord Rutherford helped found, and was President of, the Academic Assistance Council which aided displaced academics. This was to be one of the biggest mass migrations of scientists the world had seen and it began the transference of the centre of science from Europe to America. As the clouds of war once more gathered overEurope, Rutherford presided over a meeting of theCambridge University branch of the Democratic Front in which he made a case for an international ban on the use of aeroplanes in warfare. These aspects of his life's work are nigh forgotten but deserve greater recognition.

Ernest Rutherford died aged 66 onthe 19th of October 1937, the result of delays in operating on his partially stangulated umbilical hernia. His ashes were interred in London's Westminster Abbey, under an inscribed flagstone near the choir screen in the Nave. When JJ Thomson died in 1940 he was interred next toRutherford. Newton presides above them and they are surrounded by other greats of British science.


During his lifetimeRutherford was awarded many scientific prizes and honorary degrees from many countries and Fellowships of many societies and organizations (such as the Royal College of Physicians and the Institution of Electrical Engineers). Among other honors he was elected President of the Royal Society (1926-30), President of the Institute of Physics (1931-3) and was decorated with the Order of Merit (1925).

Death did not stop the public acclamation. Many buildings in many countries have been named in his honour. He has appeared on the stamps of four countries;Sweden (1968), Canada (1971), Russia (1971) and New Zealand (1971 and 2000). Curiously, he has never featured on a British stamp. In 1991 the Rutherford Origin was built on the site of his birth in rural Nelson. It incorporates into a garden setting a permanent outdoor display of information about his life and work and is open all hours. In November of 1992 he featured on the new NZ$100 banknote. Because it is the highest denomination banknote his image regularly appears as background on TV news items, and TV and newspaper advertisements, involved with finance.

His humility should also be a memorial.

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