Sir James Chadwick

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Sir James Chadwick

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About Chadwick

• Chadwick was born in Cheshire England, on Oct.
  20, 1891.
• He attended Manchester University in 1908
• In 1911 he graduated from Honors School of
  Physics
• He spent the next two years working with
  Professor Rutherford on the problem of radiation.

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Components of Chadwicks Model

• The electron had already been developed in 1894.
• The proton was also already developed in 1911.
• His addition to the model was the neutral
  particle located in the nucleus, known as the the
  neutron.

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Properties of a Neutron

• A Neutron is neutrally charged, meaning it is not
  positive or negative.
• It is the same size as the proton.
• Its mass is 1.6749286x10-27
• Its purpose is to hold the nucleus together by
  standing in between the protons so they dont
  repel each other.

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Chadwicks Theory

• Chadwick didnt have a theory.
• He built off Rutherfords theory that atoms were
  made up of a nucleus of positive particles and
  rings of electrons around it, which are
  negatively charged.

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Chadwicks Discovery

• In 1932 after eight long years of work Chadwick
  made a discovery that would rock the atomic
  world. He discovered the neutron.
• In 1935 he was awarded the Nobel Prize for
  physics for his amazing discovery.

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Effects on the World

• Chadwicks discovery was directly connected to
  the creation of the first atomic bomb in the
  Manhattan Project.
• It lead to the creation because they could break
  down Uranium 235 into a pure form to create a
  bomb.
• The discovery of the neutron was used to isolate
  neutrons, and they used them to split the atoms
  which created the radiation.

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Technology of the 20s and 30s

• In his time Chadwick had it much tougher than we
  have it now.
• Telephones were not widely used and televisions
  were not very developed, so getting information
  and sharing information was very tough.
• Calculators and computers were also non-existent
  so all calculations had to be done by hand.

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Scientific Basis

• To prove Neutrons existed Chadwick launched
  alpha-particles into Beryllium which released
  onto the paraffin wax and had no charge, thus
  they were neutrons.

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THE END