Nuclear Chemistry Aim Nuke1 What is radioactivity?

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Nuclear ChemistryAim Nuke1What is
radioactivity?
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A Brief History of Nuclear Chem

• 1895 - Wilhelm Roentgen German
• discovered X-rays, a powerful form of
  electromagnetic energy
• 1896 - Henri Becquerel - French
• discovered radioactivity when he left uranium on
  top of photographic film
• also suffered radiation burns from a sample of
  radium in his pocket

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A Brief History of Nuclear Chem

• 1898 - Henri and Marie Curie French
• using radiometry (the measure of electromagnetic
  energy strength and distribution)
• separated uranium ore into different fractions
• Discovered thorium, polonium (named for Poland,
  where Marie was originally from) and
  radium

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A Brief History of Nuclear Chem

• 1899 - Ernst Rutherford - English
• showed that radioactive decay can be described
  by a simple equation
• implying that a given radioactive substance has a
  characteristic "half-life"
• the TIME taken for HALF THE AMOUNT of
  radioactivity present in a source to decay
• He also coined the terms
• alpha particle, beta particle, and gamma rays
• he converted nitrogen into oxygen (first example
  of artificial transmutation)
• Theorized there were particles called neutrons

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A Brief History of Nuclear Chem

• 1932 James Chadwick
• Discovers Rutherfords neutrons
  through experimentation
• He shot alpha particles through a beryllium
  sheet, and through a layer of wax
• Detected protons at the end of the process

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A Brief History of Nuclear Chem

• 1938 Otto Hahn, Lise Meitner, and Fritz
  Strassmann
• became the first to split uranium atoms by
  bombarding them with neutrons
• Measureable amounts of energy released
• Coined the name fission, after binary
  fission in biology
• Small nuclear reaction!

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A Brief History of Nuclear Chem

• 1939 Leo Szilard
• Writes a letter with fellow scientists to
  President Franklin D. Roosevelt
• Warns of the potential of fission as a
  potentially devastating weapon
• Nazis in Germany were working already working on
  developing it
• Albert Einstein signs the letter to add his
  support
• Result
• Roosevelt authorizes a small study into uranium.
• US, UK, and Canada begin work on the atomic bomb

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A Brief History of Nuclear Chem

• 1942 Enrico Fermi
• successfully created the first man-made
  nuclear chain reaction
• Squash court under the stadium at the University
  of Chicago
• Also almost created the first nuclear meltdown
• On that same squash court
• Meltdown
• the nuclear material inside the reactor overheats
• Melts through building
• Heads toward China
• Also called the China Syndrome

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A Brief History of Nuclear Chem

• 1939-1945 The Manhattan Project
• a research and development project that
  produced the first atomic bombs during
  World War II.
• July 16th, 1945
• Trinity Test at Los Alamos
• First nuclear bomb test
• Upon seeing the destructive power of the atomic
  bomb, Robert Oppenheimer, project leader, quotes
  the Bhagavad Gita, a Hindu text, saying
• Now I am become death, the destroyer of worlds

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A Brief History of Nuclear Chem

• August 6th, 1945
• a uranium bomb, Little Boy, dropped on Hiroshima
  Japan
• August 9th, 1945.
• a plutonium bomb, Fat Man, dropped on Nagasaki,
  Japan on
• The cities are devastated, with up to 250,000
  people dead.
• Japan surrenders unconditionally 6 days later,
  on August 15th, 1945.
• Use of the atomic bombs ends World War II
• US does not have to invade Japan, saving millions
  of lives both Japanese and Allied
• Controversy still surrounds the decision to use
  the weapon even till today