Download Thompson`s Cathode Ray Tube Experiment

Drill – 10/12
Who was your scientist from last class?
Was his model of the atom what we accept
today? Was it completely wrong?
To Conclude
• What is our current model of the atom
called?
• Are the previous models completely
wrong?
• Next class is PSATs. Thursday we will
review scientists and go into atomic
conversions.
Drill – 10/13
What is everything that is inside an atom?
Thompson’s Cathode Ray
Tube Experiment
Cathode Ray Tube
Demonstration
Cathode Ray Tubes
• Cathode rays are beams of current.
• They are emitted from a negative terminal,
called a cathode, and travel to the positive
terminal, called the anode.
Magnets
• Magnets have a positive
and a negative side.
• Positive is attracted to
negative
• Negative is attracted to
positive
Cathode Rays
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Cathode Rays
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Cathode Rays
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Cathode
CathodeRays
Rays
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Cathode Ray Tube
Demonstration
Conclusions from the Cathode Ray
Tube
• From these experiments, J.J.
Thompson concluded that cathode
rays are made up of negatively
charged particles.
• It did not matter what element was
put into the cathode ray tube, they all
had negative particles that behaved
the same way.
• These negative particles that all
atoms have are called ELECTRONS!
• Called the plum pudding model
Rutherford’s Gold Foil
Experiment
Rutherford’s Experiment
• An experiment by Ernest Rutherford in
1911.
• He bombarded gold atoms with positively
charged particles called alpha particles.
• Rutherford knew when the positively
charged particles hit something because
instead of passing straight through the
gold foil they would bounce back or be
deflected.
Rutherford’s Conclusions
• In Rutherford’s experiment, it seemed that he
was required to send an incredible number of
missiles to get a “hit.”
• He concluded that the grid of the atom must be
composed of tiny, tiny cells and only one cell
contains all of the positive charge of the atom
• The atom is made up of mostly empty
space with a small positively charged
nucleus in the center.
• We now know that protons and neutrons
make up the nucleus.
Bohr
• Planetary Model of the atom
Heisenberg & Schrödinger
• Their ideas together gave us the
ELECTRON CLOUD model. This is our
current atomic model.
• Quarks – make up protons and neutrons.
6 types of quarks differ in mass and
charge – up, down, strange, charmed,
bottom, top.
• Leptons – make up electrons
• Gluons – hold quarks together (like glue!)
• Mesons – composed of one quark and
one antiquark. Responsible for the forces
in the nucleus.
Antimatter
i. What do you think antimatter is?
ii. Where do you think antimatter came
from?
iii. Where is all the antimatter now?