Ernest Rutherford

Until Ernest Rutherford was born in Nelson in 1871.

Ernest was, by all accounts, a very clever child. He breezed through school, where he seems to have had the quintessential New Zealand education – he was head boy and in the first XV Rugby team at Nelson College. He won one of only ten scholarships to attend university, and went on to Canterbury University, completing a B.A. in pure mathematics and Latin in 1892, an M.A. with a double first in mathematics and physical science in 1893, and a B.Sc in geology and chemistry in 1894. He published a couple of scientific papers, which got him noticed overseas as an outstanding innovator in the forefront of electricity research.

Ernest was awarded the 1851 Exhibition Scholarship – the only one available in New Zealand to study overseas at the time. He moved to England in 1895 and began as a research student at the distinguished Cavendish College in Cambridge under Professor J.J. Thompson – the first ever non-Cambridge graduate to be honoured in such a way.

Ernest did extremely well in this role, contributing a lot to the work at the laboratory, and gaining an invitation to work at McGill University in Montreal, Canada – a role he took up eagerly. It was at McGill that he made his first major discovery in science – that atoms can spontaneously transmute into other elements through radioactivity. It was this work in explaining radioactive decay that won him the Nobel Prize in 1908.

Ironically, the prize was for chemistry, not physics, yet Ernest described himself as a physicist first and foremost. As a by-product of this research into radioactivity, Ernest invented radiometric dating, suggesting it could be used to finally give an accurate age for the Earth – which it eventually did. He also invented the terms ‘alpha ray’, ‘gamma ray’ and ‘half-life’ to help describe radioactivity.

Returning to England in 1907, he worked first at the University of Manchester, then back at the Cavendish laboratory, where he made his next significant breakthrough. Ernest devised a plan to derive the internal structure of the atom.

The process involved beating gold foil until it was just a few atoms thick, then firing ‘alpha particles’ at it. Alpha particles are relatively large collections of atoms and the scientists at the time expected they should punch through the thin foil easily – which they did… mostly. But every now and then one bounced back. This was completely unexpected for Ernest, who said it was as “if you fired a 15-inch shell at a sheet of tissue paper and it came back to hit you.”

He deduced from this result that the atom, rather than being a single indivisible particle, was mostly just empty space, but with something very small and very dense in the middle – dense enough to send that alpha particle bouncing back. Most of the alpha particles pass right through the empty space, but every now and then one of them smacks into the bit in the middle – the nucleus – and is deflected right back. Ernest had shown that the atom was made up of smaller ‘things’ arranged a bit like a solar system – small electrons orbiting a small nucleus. He had, theoretically at least, split the atom. It is hard to think of any discovery in all of science which was more important in the quest to find out what the universe is.

Not content to finish there, Ernest Rutherford went on to actually split the atom in 1917. He bombarded nitrogen atoms with alpha particles and witnessed them split into oxygen. It was the first time a person had ever performed the alchemy of changing one element into another. This experiment was Ernest Rutherford’s third great achievement, and of course seeded the idea of nuclear fission, which others would go on to develop in a myriad of ways.

Ernest Rutherford’s place as one of the greatest scientists of all time cannot be overestimated. Biographers wrote that he is to the atom what Darwin was to evolution, Newton to mathematics and Einstein to relativity. Ernest Rutherford’s greatest achievement, however, may have been as a teacher and mentor to many of the next generation of eminent scientists – names like Chadwick, Bohr, Oppenheimer and Geiger all learnt their craft from the humble New Zealander with the big voice. Ernest valued the simple explanation of his craft, saying at one point that

“an alleged scientific discovery has no merit unless it can be explained to a barmaid.”

In his lifetime, Ernest Rutherford was awarded the Nobel Prize, 21 honorary degrees, and countless awards. He was knighted in 1914 and made a Baron in 1931. As ‘Baron Rutherford of Nelson’ he chose a coat of arms that included a kiwi and a Māori warrior.

The story goes that as Ernest lay on his deathbed in 1937, at the age of 66, he called for his wife, Mary, to make a donation of 100 pounds to Nelson College, his alma mater. Today Ernest Rutherford’s wish is honoured with his face adorning New Zealand’s $100 note.