Sara Reausaw

1
Sara Reausaw Department of Chemistry and
Chemical Engineering South Dakota School of
Mines and Technology Rapid City, SD 57701
Rutherford The Friendly Physicist who Advanced
in Chemistry


Biography on the life of Ernest Rutherford
Rutherford's Gold Foil Experiment
Rutherford and Geiger together at Manchester
developed a device that was able to count alpha
particles when it detected them. The new detector
consisted of a screen coated with zinc sulfide.
Alpha particles would hit the screen and emit a
tiny flash of light. Geiger had to peer at the
screen through a microscope in order to see the
emission that was termed scintillation. Geiger
felt that the time had come to perform an
experiment. Rutherford noticed alpha particles
were colliding with the atoms in the foil. The
particles were bouncing off at small angles and
this type of interaction is said to be scattered.
By counting the scattered particles, Rutherford
and Geiger hoped to learn something about atoms.
Geiger put a thin foil in front of the narrow
beam of particles. The alpha particles went
through the foil and exited the other side in a
scattered manner. It was calculated that
throughout the entire foil, the average angle of
deflection of an alpha particle was less than one
degree from the center path.
Before Ernest Rutherford was born in 1871 his
family immigrated to New Zealand from England.
Ernest was born on a farm near Nelson that his
family ran successfully. He was the fourth of 12
children and enjoyed the hard work associated
with the life of being on a farm. He was a good
student in school and won a university
scholarship to Canterbury College. Here he no
doubt was exposed to liberal education. For
this was a Christchurch, and in 1892 graduated.
Here at Canterbury he had majored in mathematics
and physics. He decided to stay at Canterbury
College for a further year to continue studying
and and to teach. It was during this year that
he studied the properties of iron in
high-frequency alternating magnetic fields.
Cambridge University in England awarded him
yet another scholarship to further his education.
At twenty-four years old left his fiancee, Mary
Newton, in September 1895, to work in the
Cavendish Laboratory at the university. This
proved to be a turning point in his life. He had
brought an electromagnetic wave detector with
him, and discovered a way to detect radio signals
using magnetized steel needles. In Cambridge he
sent a message three quarters of a mile away. A
man by the name of J.J. Thompson was impressed
with the talents that Rutherford possessed and
invited him to collaborate with him. This was the
start of a promising career in atomic physics.
Early on he found that all known radioactive
elements emit two kinds of radiation positively
and negatively charged. Rutherford was
responsible for the naming of these terms as
alpha and beta. He discovered the half-life by
showing that every radioactive element decreases
in radioactivity over a unique and regular time,
ultimately becoming stable. Frederick Soddy
worked with him in 1901 and 1902, and they proved
that by expelling a piece of the atom at high
velocity, atoms of one radioactive element would
spontaneously turn into another. The idea was
frowned upon as it was thought to be alchemy.
Their beliefs that the atom is indivisible and
unchangeable gained recognition by 1904, along
with Rutherfords achievements and publications.
His achievements and publications intertwined as
he published eighty papers in the span of seven
years. In 1898 McGill University, Montreal
called the twenty-seven year old Rutherford to
head up the Physics Department. McGill
Universitys topic of interest fell in the work
of subatomic physics. This new science was at the
hands of Rutherford and his team. They researched
the phenomenon of natural radiation. Rutherford,
at McGill University, put much investigation in
answering the question about what these rays that
were capable of passing in various degrees
through many substances impervious to light were.
It was at this time that he had planned to
finally marry his fiancée Mary Newton, yet it was
another year and a half before the two became
husband and wife. In 1907 he went to accept a
chair at the University of Manchester and came
in contact with a man by the name of Geiger.
Together they set up a center to study radiation.
In 1909 Rutherford began performing experiments
that would all together change the views upon
physics. He discovered the atomic nucleus and
developed a model of the atom that resembled the
solar system. The nucleus resembled the sun and
the electrons resembled the planets in orbit
around the sun. Niels Bohr modified the theory by
using quantum theory, and this increased the
acceptance of the theory all together. During
World War I, he left his research to help the
British Admiralty with the practical problem of
submarine detection. By underwater acoustics he
managed to dislodge a single particle that
possessed a positive charge. This meant that it
must have come from nucleus Rutherford named
this new particle a proton. This was the first
nuclear reaction, and he was the man
responsible for it.
It was of some interest to see if any of the
alpha particles were in fact deflected more than
ninety degrees this would in turn indicate that
some of the alpha particles were returning
towards the source. To both Grieger and
Rutherfords surprise, measurements indicated
that about one in eight thousand was deflected by
a large angle. Rutherford came up with the
explanation that the alpha particles must be
colliding with something inside the atom that was
small and heavy. This center of the atom that is
small and heavy is called the nucleus.
Nobel Prize Award
Rutherford received the 1908 Nobel Prize in
chemistry for his work in dealing with radiation
and the atomic nucleus. It was somewhat
surprising that a physicist would be awarded the
prize in chemistry. During the time in which
Rutherford lived, nuclear physics and nuclear
were one of the same. Since Rutherford was a
Physicist he was slightly put out by the award in
chemistry.
References

• http//www.xmission.com/dparker/nucleus.html
• http//www.watertown.k12.wi.us/hs/teachers/buesc
  her/atomtime.asp
• http//windows.arc.nasa.gov/cgi-bin/tour.cgi?lin
  k/people/modern_era/rutherford.html
• http//www.chemistry.co.nz/ernest_rutherford.htm
  
• http//www.pbs.org/wgbh/aso/databank/entries/bpr
  uth.html
• http//www.blupete.com/Literature/Biographies/Sc
  ience/Rutherford.htm
• http//www.cbc4kids.ca/general/the-lab/big-bang/
  99-09-10/default.html
• http//dbhs.wvusd.k12.ca.us/Gallery/Gallery11.ht
  ml
• http//www.accessexcellence.org/AE/AEC/CC/histor
  ical_background.html

Chem 292, Chemistry Outreach Spring 2001 Dr.
David A. Boyles and Dr. M. Steven McDowell