Subatomic Particles

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Subatomic Particles
Ashley Fagan Ainslie Thompson Alanna Murphy Aja
Lapointe Shanna Fredericks Melanie MacDonald
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(No Transcript)
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The Discovery of Subatomic Particles

• On April 30,1897 J.J. Thomson discovered the
  electron

• Professor Thomson used a simple velocity selector
  device in combination with a
• cathode-ray tube.

• Subatomic particles were accelerated from the
  cathode (-) to the Anode () with
• a known speed

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The definition of a subatomic particle according
to the American Heritage Dictionary is Any of
various units of matter below the size of an
atom, including the elementary particles and
hadrons.
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Subatomic Particles The diameter of a single
atom ranges from 0.1 - 0.5 nm (1 nm 10-9m) As
small as the atom is, it is made of smaller
subatomic particles Electrons, Neutrons, and
Protons
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Quark is a theoretical particle that is
believed to be the constituent of hadrons.
Lepton A class of light, elementary subatomic
particles which have no constituent parts.
Neutrino is an essentially massless, neutral
lepton.
Hadron A class of subatomic particles which do
have constituent parts.
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What is a Quark? Quarks were "invented" by
Murray Gell-Mann and George Zweig of Caltech in
1964. The name "quark" apparently originated in
the phrase "three quarks" used by James Joyce in
his novel Finnegans Wake.
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• The Quark Mass is so small that they could
  probably travel through a mile and a half
  thickness of lead without hitting another
  particle.
• Quark Confinement
• Quarks can not exist by themselves.
• All quarks must be bound to another quark or
  antiquark by the exchange of gluons.

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What is a lepton?
There are six leptons, three of which have
electrical charge and three of which don't. The
best known charged lepton is the electron (e).
The other two charged leptons are the muon (µ)
and the tau, which are electrons with a lot more
mass. The charged leptons are all negative. The
other three leptons are the neutrinos. They have
no electrical charge and little, if any, mass.
There is one type of neutrino for every type of
electrically charged lepton.
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• Half a century ago, a physicist "invented" the
  neutrino to make an equation balance. It was an
  odd particle, to say the least. Tiny, energetic,
  with no mass or electric charge, and it was
  virtually undetectable.

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• Hard to see or not, scientists now believe that
  nature is full of the shadowy neutrino. According
  to rough calculations, a hundred trillion
  neutrinos whistle through your body every second.

• Some varieties of neutrino can even pass right
  through the Earth --and giant clouds of
  interstellar
• gas and dust-without leaving a trace, and without
  being changed in the process.

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Hadrons
Hadrons have no net strong charge (or color
charge) but they do have residual strong
interactions due to their color-charged
substructure. Many types of hadrons were
discovered in the 50's and 60's. The idea of the
quarks was first proposed to explain the many
observed hadrons. There are two classes of
hadrons baryons and mesons.
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The End!