Ernest Rutherford

Mark Ibañez
May 14, 2018

Submitted as coursework for PH241, Stanford University, Winter 2018

Background

Fig. 1: Ernest Rutherford- The founder of Nuclear Science. His remarkable discoveries of the concept of radioactive half-life, of the α and β particles, the atomic nucleus, and the proton contribute to his renowned status as a Nobel Laureate. (Source: Wikimedia Commons)

Ernest Rutherford (1871-1937) was a physicist who lead the charge in the study of radioactivity, and ultimately unearthed the continued exploration of nuclear physics. Rutherford was born in Spring Grove, on the South Island of New Zealand on August 30, 1871. [1] At a very young age Rutherford cultivated a deep interested in science and scientific experimentation, and thus he was awarded a scholarship to attend Nelson Collegiate School, a private secondary school, in 1887. Then in 1889 he was awarded yet another University scholarship to attend the University of New Zealand, Wellington, from which he would enter the Canterbury College and graduate M.A. in 1893 with a double first in Physical Science and Mathematics. [1] During his time at Canterbury, Rutherford met the love of his life, Mary Newton, and the couple married in the early 1900's. Shortly after, he was awarded the Nobel Prize in Chemistry in 1908. Ernest Rutherford continued to unearth scientific marvels until his death in 1937. [1] A portrait of Ernest Rutherford is shown in Fig. 1.

Research and Discoveries

At Canterbury Rutherford conducted several independent research studies involving radioactivity; so many, that he was able to receive a Bachelor of Science degree in one year. Shortly thereafter, Rutherford became a full time research Student at the University 0f Cambridge's Cavendish Laboratory in London, where he worked to identify radio waves more efficiently. [2] During his time at the Cavendish Laboratory he worked with Professor J. J. Thomson, studying X-rays. The two were interested in the numerous effects that X-rays would have on the conductivity of gases, ultimately focusing on the division of atoms and molecules into ions.

Rutherford and Thomson separated as partners and Rutherford became more interested in ion-producing radiations. One of Rutherford's most notable achievements and contributions to the nuclear age occurred when he began a new professorship at the University of Manchester. He wanted to experiment with the theory of uranium radiation. Rutherford hypothesized that the rays emitting from uranium would be complex, so he proposed that testing how well the rays permeated different metal foils may help show what the different characteristics of the rays were. [3] To explore this Rutherford covered uranium with a thin sheet of metal foil, and then intended to measure the "rate of leak," which would indicate a specific amount of current. Rutherford experimented with placing multiple sheets of metal and aluminum foil in order to observe how much the rate of leak would increase or decrease, while also observing how much of the radiation would be blocked. In his final test using aluminum foil (0.0005 cm thick), he found that using 12 layers, instead of his original 4, would decrease the leak rate significantly. [3] Rutherford discovered two components of the radiation and described them as α-rays and β-rays, understanding later that the radiation from uranium was composed of both α-rays and β-rays.

Ernest Rutherford then accepted a professorship at McGill University in Montreal in 1902 through which he and his colleague Frederick Soddy presented their disintegration theory of radioactivity. This theory explained how radioactive energy was emitted from within an atom and claimed that the emission of an α- or β- particle was that specific atom's transmuting from one chemical element to the other. Rutherford also conducted a number of experimental studies to prove this theory to be true.

Legacy

Ernest Rutherford's legacy persists today through the continued exploration of nuclear physics. For example, his fascinating experiment can even be recreated today. [3] In addition to this, some of his most notable discoveries became the foundation of the European Organization for Nuclear Research's construction of the Large Hadron Collider, an energy particle accelerator that smashes atomic particles. Rutherford's experiments easily prove him to be the founder of Nuclear Science.

© Mark Ibañez. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] C. L. Boltz, Ernest Rutherford (Heron Books, 1970).

[2] J. L. Heilbron, Ernest Rutherford: And the Explosion of Atoms (Oxford University Press, 2003).

[3] N. Martelaro, "Rutherford's Experiment to Understand β-rays," Physics 241, Stanford University, Winter 2017.