Books by Reeves, Richard

Reeves, Richard. A Force of Nature. New York: W. W. Norton, 2008. ISBN 978-0-393-33369-5.

In 1851, the Crystal Palace Exhibition opened in London. It was a showcase of the wonders of industry and culture of the greatest empire the world had ever seen and attracted a multitude of visitors. Unlike present-day “World's Fair” boondoggles, it made money, and the profits were used to fund good works, including endowing scholarships for talented students from the far reaches of the Empire to study in Britain. In 1895, Ernest Rutherford, hailing from a remote area in New Zealand and recent graduate of Canterbury College in Christchurch, won a scholarship to study at Cambridge. Upon learning of the award in a field of his family's farm, he threw his shovel in the air and exclaimed, “That's the last potato I'll ever dig.” It was.

When he arrived at Cambridge, he could hardly have been more out of place. He and another scholarship winner were the first and only graduate students admitted who were not Cambridge graduates. Cambridge, at the end of the Victorian era, was a clubby, upper-class place, where even those pursuing mathematics were steeped in the classics, hailed from tony public schools, and spoke with refined accents. Rutherford, by contrast, was a rough-edged colonial, bursting with energy and ambition. He spoke with a bizarre accent (which he retained all his life) which blended the Scottish brogue of his ancestors with the curious intonations of the antipodes. He was anything but the ascetic intellectual so common at Cambridge—he had been a fierce competitor at rugby, spoke about three times as loud as was necessary (many years later, when the eminent Rutherford was tapped to make a radio broadcast from Cambridge, England to Cambridge, Massachusetts, one of his associates asked, “Why use radio?”), and spoke vehemently on any and all topics (again, long afterward, when a ceremonial portrait was unveiled, his wife said she was surprised the artist had caught him with his mouth shut).

But it quickly became apparent that this burly, loud, New Zealander was extraordinarily talented, and under the leadership of J.J. Thomson, he began original research in radio, but soon abandoned the field to pursue atomic research, which Thomson had pioneered with his discovery of the electron. In 1898, with Thomson's recommendation, Rutherford accepted a professorship at McGill University in Montreal. While North America was considered a scientific backwater in the era, the generous salary would allow him to marry his fiancée, who he had left behind in New Zealand until he could find a position which would support them.

At McGill, he and his collaborator Frederick Soddy, studying the radioactive decay of thorium, discovered that radioactive decay was characterised by a unique half-life, and was composed of two distinct components which he named alpha and beta radiation. He later named the most penetrating product of nuclear reactions gamma rays. Rutherford was the first to suggest, in 1902, that radioactivity resulted from the transformation of one chemical element into another—something previously thought impossible.

In 1907, Rutherford was offered, and accepted a chair of physics at the University of Manchester, where, with greater laboratory resources than he had had in Canada, pursued the nature of the products of radioactive decay. By 1907, by a clever experiment, he had identified alpha radiation (or particles, as we now call them) with the nuclei of helium atoms—nuclear decay was heavy atoms being spontaneously transformed into a lighter element and a helium nucleus.

Based upon this work, Rutherford won the Nobel Prize in Chemistry in 1908. As a person who considered himself first and foremost an experimental physicist and who was famous for remarking, “All science is either physics or stamp collecting”, winning the Chemistry Nobel had to feel rather odd. He quipped that while he had observed the transmutation of elements in his laboratory, no transmutation was as startling as discovering he had become a chemist. Still, physicist or chemist, his greatest work was yet to come.

In 1909, along with Hans Geiger (later to invent the Geiger counter) and Ernest Marsden, he conducted an experiment where high-energy alpha particles were directed against a very thin sheet of gold foil. The expectation was that few would be deflected and those only slightly. To the astonishment of the experimenters, some alpha particles were found to be deflected through large angles, some bouncing directly back toward the source. Geiger exclaimed, “It was almost as incredible as if you fired a 15-inch [battleship] shell at a piece of tissue paper and it came back and hit you.” It took two years before Rutherford fully understood and published what was going on, and it forever changed the concept of the atom. The only way to explain the scattering results was to replace the early model of the atom with one in which a diffuse cloud of negatively charged electrons surrounded a tiny, extraordinarily dense, positively charged nucleus (that word was not used until 1913). This experimental result fed directly into the development of quantum theory and the elucidation of the force which bound the particles in the nucleus together, which was not fully understood until more than six decades later.

In 1919 Rutherford returned to Cambridge to become the head of the Cavendish Laboratory, the most prestigious position in experimental physics in the world. Continuing his research with alpha emitters, he discovered that bombarding nitrogen gas with alpha particles would transmute nitrogen into oxygen, liberating a proton (the nucleus of hydrogen). Rutherford simultaneously was the first to deliberately transmute one element into another, and also to discover the proton. In 1921, he predicted the existence of the neutron, completing the composition of the nucleus. The neutron was eventually discovered by his associate, James Chadwick, in 1932.

Rutherford's discoveries, all made with benchtop apparatus and a small group of researchers, were the foundation of nuclear physics. He not only discovered the nucleus, he also found or predicted its constituents. He was the first to identify natural nuclear transmutation and the first to produce it on demand in the laboratory. As a teacher and laboratory director his legacy was enormous: eleven of his students and research associates went on to win Nobel prizes. His students John Cockcroft and Ernest Walton built the first particle accelerator and ushered in the era of “big science”. Rutherford not only created the science of nuclear physics, he was the last person to make major discoveries in the field by himself, alone or with a few collaborators, and with simple apparatus made in his own laboratory.

In the heady years between the wars, there were, in the public mind, two great men of physics: Einstein the theoretician and Rutherford the experimenter. (This perception may have understated the contributions of the creators of quantum mechanics, but they were many and less known.) Today, we still revere Einstein, but Rutherford is less remembered (except in New Zealand, where everybody knows his name and achievements). And yet there are few experimentalists who have discovered so much in their lifetimes, with so little funding and the simplest apparatus. Rutherford, that boisterous, loud, and restless colonial, figured out much of what we now know about the atom, largely by himself, through a multitude of tedious experiments which often failed, and he should rightly be regarded as a pillar of 20th century physics.

This is the thousandth book to appear since I began to keep the reading list in January 2001.

February 2015