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Insight and Influences
Ernest Rutherford was one of the first leading scientists of his time in the complex field of nuclear physics. Some might even say that he was one on the most important contributor. Soon after the discovery of radiation by French physicist Antoine Henri Becquerel in 1896, Rutherford identify the three major components of radiation. He named them alpha, beta, and the last gamma rays. He then proved that the alpha rays contained a helium nuclei. Because of his discoveries, scientists were able to come up with another theory of the
Image courtesy of www.odt.co.nz
arrangement of an atomic structure that is still accepted today. It was the first theory that described the nucleus was dense and made up of neutrons and protons and that electrons orbit around it. That was his first major breakthrough.
Then in 1919 was the first to artificially induced a nuclear reaction. In his experiment, he shot alpha particles at nitrogen gas and that unexpectedly resulted in atoms of an oxygen isotope and protons. That transmutation of nitrogen into oxygen jump started the urgent research of radiation.
Insight and Influences
James Rutherford, who was a Scottish wheelwright, moved to New Zealand along with his father in 1842. A couple of years later in 1855, Martha Thompson along with her widowed mother also moved to New Zealand. She was in school as an English teacher prior to moving to New Zealand. They later married and had 12 kids together. It was a large family with seven boys and five girls. Their fourth child, however, turned out to be successful made a significant impact on the lives of many. That child, named Ernest Rutherford, was born on August 30 of 1871 in Nelson. Nelson was located near the center of New Zealand and was the center of art and crafts. His childhood through his adolescent and part of his adult life revolved around his education. He attended Nelson Collegiate School at the young age of 16. He then received a University scholarship to the University of New Zealand in Wellington in 1889. His educational achievements included graduating with a Master of Arts and a Bachelor of Science. Then in 1894, he received a Exhibition Science Scholarship which allowed him to attend Trinity College in Cambridge. There he studied at the Cavendish Laboratory with his professor J.J. Thompson. He graduated with a Bachelor of Arts Research Degree a year later. That same year he was awarded the Courts-Trotter Studentship from Trinity College. After graduating from school he spent more time focusing on Science and Physics. He moved to Montreal, Canada in 1898 to take the MacDonald Chair of Physics at McGill University. Then in 1907 he succeeded Sir Arther Schuster who was a Langworthy Professor Of Physics at the University of Manchester. After that he succeeded Sir Joseph Thompson who was a Cavendish Professor of Physics at Cambridge. Rutherford astounded many including Thomson when he arrived because he invented a device to detect electromagnetic waves. During his stay at New Zealand, he wrote a thesis named
Magnetization of Iron by High-Frequency Discharges
which was his first research. For it experimented with high-frequency AC. Soon after the Transactions of New Zealand Institute published his paper named
which was his second paper. In it he described a device capable of measuring time to a hundred-thousandth of a second.
Perhaps the most crucial experiment of Rutherford was his gold foil experiment he did while he was at McGill University. In his experiment, he shot a beam of alpha particles at a thin sheet of gold. His expectations were that they would all pass through. His results, however, were truly surprising. He once stated that "
if one had fired a large naval shell at a piece of tissue paper and it had bounced back." For his experiment, he had a alpha particle emitter aimed at a sheet of thin gold. Around it he placed a sheet coated with zinc sulfide to detect where the alpha particle traveled after colliding with the sheet of gold. Most alpha particle passed through. However, some were deflected at at a wide angle but the most puzzling was that a few deflected directly in the opposite direction of travel after colliding with the sheet of gold. Based on the results, he concluded that the vast majority of an atom's mass were concentrated in
Image courtesy of www.nobelprize.org
the center, or nucleus. His conclusion derived from his test that showed approximately 1 in 8000 alpha particle was deflected while the rest passed through completely. From that he also stated that most of atom was empty space.
His results disproved Thomson's "plum pudding" theory which stated that the mass of an atom was spread throughout. If Thomson's model is correct then there would be little to nothing to deflect the alpha particle back because all the mass is spread out. The only way the alpha particle could be deflected was that if it struck something very dense and or hard like the nucleus. This lead him to develop his own theory which is still accepted today. He was the first to describe the atom as having a dense nucleus with protons and a relatively loose surrounding where the electrons orbit around the nucleus.
Ernest Rutherford's life is nothing short of extraordinary. He was able to accomplish so much given he only had 66 years to do it all. Fortunately for us today he sacrificed his childhood and adolescent for school. He did not have much time to enjoy his early years. He bought his first car in 1910 when he was 39. His accomplishment in school, which includes graduating with a MA and a BA, although impressive is nothing compare to his accomplishment in life. In 1899 he was the first to discover two major components of radiation. Alpha and beta rays was what he named them. That same year he also proposed that within the nucleus exists a neutral component. However, it wasn't until 1932 that it was proven to exist. He also proved that alpha rays were helium nuclei. In 1911, the year he conducted his famous gold foil experiment, he deduced from his experiment that the majority of the mass of an atom is concentrated in the nucleus. Because of the gold foil experiment, he was able to prove that Thomson's plum pudding model was not correct. If it were correct then there would be very little to deflect the alpha particles back. In 1899 he was able to show the concept the smoke detector. In 1911, he announced his atomic structure theory. He believed that the the nucleus contained much of the mass and positively charged protons while the negatively charged electrons orbit. As of now that theroy has yet to be disproven. In 1915 he was one of the first few to began to develop acoustic means to detect submarines because of the war. In 1917, he became the first to artificially induced a nuclear reaction turning nitrogen into oxygen. He came to rest in 1937 after his father died in 1928 and his mother in 1935. He was buried in Westminister Abbey.
Rutherford Gold Foil Experiment
Insight and Influences
Rutherford Atomic Theory
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