The People Behind The Curtain: Ernest Rutherford

"For Mike's sake, Soddy! Don't call it transmutation. They'll have our heads off as alchemists."

-- Ernest Rutherford

 If there had to be one scientist I could choose to be my grandpa, it would be Ernest Rutherford. He has just the right ratio of quirk to genius, and, with eleven protégés becoming Nobel Prize winners themselves, I'd say he would be the perfect man to teach me about life.

Look at that glorious mustache! 

Ernest Rutherford was born 1871 in New Zealand  and was raised on a flax farm where he didn't get his first taste of academia until, at the age of ten, he received a textbook that he read and reread. He eventually went on to Nelson and Canterbury Colleges, and, in order to work on early radio wave technology, he moved to England to do his postdoctorate at Cambridge. After becoming knighted for developing ways to better detect submarines, he became the director of the University of Manchester's physics lab.

However, Rutherford did not quite fit in with the stuffy scientists in England. He was utterly ridiculous. As a lab director he sported a dense walrus mustache, walked around campus carrying radioactive elements in his coat pockets, and reliably smelled like the cigars and pipe tobacco he smoked. On top of that, he shouted bizarre euphemisms ("For Mikes's sake") instead of swearing, which he would often do at his lab equipment if they wouldn't cooperate, and sang "Onward, Christian Soldiers" loudly, without reason, and usually off pitch. Once, Rutherford even remarked that he "felt like an ass in lion's skin," because, as a boisterous farm boy, he couldn't relate with his reserved colleagues.

Despite (or, perhaps, because of) his abrasive and hilarious personality, Rutherford would end up doing his most influential work with nuclear physics there. I am going to explain three of his most popular experiments: where he discovered that radioactive elements transform as they decay (Radium => Radon), where he proved the existence of radioactive alpha particles released from decay and that they are actually the gas helium (Two Glass Bulbs), and his most famous work, where he proved the existence of a small but dense positively charged nucleus (Gold Foil).

Radium => Radon Experiment

After Marie and Pierre Curie's work with radioactivity in the late 1800's, it was understood that radiation spread outward from a radioactive element. Many people thought that it was spread by a gas of some sort, similar to the idea of an "ether" that most doctors earlier in the century believed spread illness before the germ theory was developed. Rutherford set out to find out what kind of gas was being released and spreading the radiation.

To do this he and his partner, Fredrick Soddy, placed a sample of radium in a container full of water and collected the gas from the bubbles forming on its surface. They were thrilled when they found out that the bubbles were a new element, radon. And not only had the two scientists discovered a new box on the periodic table, but they noticed that as the amount of radon they gathered increased, the original sample of radium decreased. Ergo, radium had actually transformed into radon! Rutherford had discovered radioactive decay, and how unstable substances jump across the periodic table as they change.

Two Glass Bulbs Experiment

Helium gas being excited by electricity. This would
have been the same glow that Rutherford saw when he
ran a current through the alpha particles.

Rutherford noticed that even though elements decay, they don't decay in the obvious way by moving one place to the left on the periodic table, loosing a single atomic mass unit. Elements jump two spaces to the left, loosing two electrons as opposed to one. Rutherford named the packets of two electrons shot out of the decaying element alpha particles. Alpha particles, having two electrons and two protons, were actually single helium atoms breaking out of the large unstable element.

To prove this, Rutherford made two glass bulbs: one small and bubble thin, and one larger and thicker. He pumped radioactive gas into the small bulb which he placed in the larger bulb, and waited. The alpha particles had enough energy and were small enough to tunnel through the first glass but were stopped by the larger glass. To show that the invisible gas trapped between the bulbs was the helium alpha particles, Rutherford excited them with an electrical current and the bulb glowed the customary helium purplish color. (If you've ever seen neon lights, you'll know the glow).

Golden Foil Experiment

Or instead of reading this section, you could just watch
this .gif... 

Though Rutherford is known for this experiment it is important to note that his colleagues, Hans Geiger and Ernest Marsden, are the scientists that carried it out, even though his work made it possible. Rutherford just presented the idea and published it.

Previously, the established idea for the structure of the atom was the "plum pudding model", the thought that the atom was a positively charged mass with free-floating electrons meandering about inside like the raisins in plum pudding. Though Geiger, Marsden, and Rutherford doubted this, because they believed that there was a small positively charged nucleus that the negatively charged electrons were orbiting, much like planets around the sun (or pedophiles around an elementary school... whatever).

The scientists set up an experiment where a decaying element would shoot alpha particles into gold foil. After hitting the foil the alpha particles mostly passed through the atoms unscathed, but some veered off a few degrees as if being deflected. If the plum pudding model was correct then no particles should have been deflected because the atom would have been mostly empty space, but by measuring the angles at which the alpha particles were deflected Geiger and Marsden figured that there was a center, a nucleus, that the particles were bouncing off of.

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Works Cited

"Ernest Rutherford - Biographical." Ernest Rutherford - Biographical. 19 Aug. 2013 <http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1908/rutherford-bio.html>.

"The Gold Foil Experiment." The Gold Foil Experiment. 19 Aug. 2013 <http://myweb.usf.edu/~mhight/goldfoil.html>.

Kean, Sam. The disappearing spoon: And other true tales of madness, love, and the history of the world from the periodic table of the element. New York: Little, Brown and Company, 2010.

"Legacies- Ernest Rutherford." ThinkQuest. Oracle Foundation. 19 Aug. 2013 <http://library.thinkquest.org/07aug/00458/erutheford.html>

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