Transcript A Brief History of Nuclear Chem

Nuclear Chemistry
Aim Nuke1
What is radioactivity?
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
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
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
A Brief History of Nuclear Chem
1932 James Chadwick
Discovers Rutherford’s 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
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!
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
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”
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”
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