| Ernest Rutherford
1871 - 1937
Ernest Rutherford's family emigrated from England to New Zealand before he was born. They ran a successful farm near Nelson, where Ernest was born. One of 12 children, he liked the hard work and open air of farming, but was a good student and won a university scholarship. After college, he won another scholarship to study at Cambridge University in England -- a turning point in his life. There he met J.J. Thomson (who would soon discover the electron), and Thomson encouraged him to study recently-discovered x-rays.
This was the start of a long, productive, and influential career in atomic physics. Rutherford eventually coined the terms for some of the most basic principles in the field: alpha, beta, and gamma rays, the proton, the neutron, half-life, and daughter atoms. Several of the century's giants in physics studied under him, including Niels Bohr, James Chadwick, and Robert Oppenheimer.
Early on he found that all known radioactive elements emit two kinds of radiation: positively and negatively charged, or alpha and beta. He showed that every radioactive element decreases in radioactivity over a unique and regular time, or half-life, ultimately becoming stable. In 1901 and 1902 he worked with Frederick Soddy to prove that atoms of one radioactive element would spontaneously turn into another, by expelling a piece of the atom at high velocity. Many scientists of the day scorned the idea as alchemy. They stuck with the age-old belief that the atom is indivisible and unchangeable. But by 1904 Rutherford's publications and achievements gained recognition. He was an extremely energetic researcher: in the span of seven years, he published 80 papers.
In 1907 he went to the University of Manchester and with Hans Geiger (of the Geiger counter) set up a center to study radiation. In 1909 he began experiments that were to change the face of physics. He discovered the atomic nucleus and developed a model of the atom that was similar to the solar system. Like planets, electrons orbited a central, sun-like nucleus. Acceptance of this model grew after it was modified with quantum theory by Niels Bohr. For his work with radiation and the atomic nucleus, Rutherford received the 1908 Nobel Prize in chemistry. He was slightly put out, since he was a physicist and felt a bit superior to chemistry! In 1914 Rutherford was knighted.
During World War I, he left his research to help the British Admiralty with problems of submarine detection, but was soon back in the lab. He managed to produce the disintegration of a non-radioactive atom, dislodging a single particle. The particle had a positive charge, so it must have come from nucleus: he called this new particle a proton. With this experiment, he was the first human to create a "nuclear reaction," though a weak one. In 1919 he took over as director of the Cavendish Laboratory. His warm, outgoing personality made him an outstanding mentor to researchers attracted there by his scientific achievements.
He took on more supervision and less direct research as years went by. In 1931 he was made the first Baron Rutherford of Nelson, allowing him to join the House of Lords. He was fiercely anti-Nazi, and in 1933 he served as president of the Academic Assistance Council, established to help German refugees. He would not personally help chemist Fritz Haber, however, who had been instrumental in creating chemical weapons in World War I. Rutherford died two years before the discovery of atomic fission.
"All science is either physics or stamp collecting."