Ernest Rutherford & the Gold Foil Experiment
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Transcript of Ernest Rutherford & the Gold Foil Experiment
ERNEST RUTHERFORD& THE GOLD FOIL EXPERIMENTBy Jake Easton & James Lampmann
Birth
He was born on August 30, 1871 in Nelson, New Zealand
His parents were James and Martha Rutherford
He was one of 12 kids
Education
In 1887, he won a scholarship to Nelson College
From 1890 to 1893, he attended Canterbury College at the University of New Zealand
In 1894 he received an 1851 Exhibition Science Scholarship which allowed him to go to the Trinity College, Cambridge.
While he was there he studied as a research student under J.J. Thompson at the Cavendish Laboratory.
Jobs/ Career
In 1897 the MacDonald Chair of Physics at McGill University in Montreal, Canada became open. In 1898 he left New Zealand to take the job.
In 1907 he returned to England to become the Langworthy Professor of Physics at the University of Manchester
In 1919, he took a job as a Cavendish Professor of Physics at Cambridge.
Jobs/ Career Continued
After that he became: Chairman of the Advisory Council Department of Scientific and Industrial
Research Director of the Royal Society Mond Laboratory
at Cambridge A professor of Natural Philosophy at Royal
Institution, London
The Gold Foil Experiment
Rutherford did this experiment in 1910
He did it in order to: Learn more about
the structure of an atom
Confirm J.J. Thomson’s “plum pudding” model of an atom:
What He Accepted
Rutherford accepted that electrons were present in atoms and that they were negatively charged
He also accepted that there was something inside an atom that made it have a neutral charge and accepted the plum pudding model that had positively charged matter throughout
The Experiment
It was set up with a thick lead box with a small opening surrounding a source of heavy, alpha particles
A small beam of the particles was formed pointing at an extremely thin piece of gold foil (approximately 3.4x10-14m thick)
The Experiment Continued
He used a fluorescent rotatable detector which has a microscope and a screen coated with zinc sulphide to detect the alpha particles which he wrapped in a circle around the gold foil
The entire experiment was performed in an evacuated chamber in order to prevent scattering by the air molecules
Rutherford expected that all of the particles would go through the foil without any deflection
Results
When he performed the experiment, he received some interesting results
When the particles hit the foil, most went straight through, but some of the particles were deflected off at angles and even a few bounced right back off of the foil.
Conclusions
Since most of the particles went straight through, he concluded that most of the space in an atom is empty
Since some of the particles deflected or bounced straight back, he concluded that there must be a concentrated area that is positively charged
Also since only a very small amount of the particles were deflected, he concluded that the area of the positively charged particles must be very small
“Nucleus of an atom”
http://www.youtube.com/watch?v=Q8RuO2ekNGw
Rutherford’s Atomic Model
Was also known as the “planetary model”
It had 2 changes compared to the plum pudding model: A high concentrated area of
positively charges particles is central and very small compared to the rest of the atom (later named the nucleus)
The nucleus contains most of the atomic mass of the atom
Rutherford was the first to discover and prove the existence of positive central charge
Rutherford’s Atomic Theory
Most of the space in an atom is empty Almost all the mass of an atom is concentrated
in the center of the atom In the center of the atom there are positively
charged particles The negatively charged particles revolve around
the nucleus in different orbits The center region of the nucleus is extremely
small
Sources http://www.rutherford.org.nz/biography.htm http://www.nobelprize.org/nobel_prizes/chemis
try/laureates/1908/rutherford-bio.html http://physics.tutorvista.com/modern-physics/r
utherford-s-gold-foil-experiment.html