How Small Is It - 04 - Elementary Particles (1080p)
Δημοσιεύτηκε στις 2 Δεκ 2014
Text at http://howfarawayisit.com/documents/
In this segment of our “How small is it” video book, we introduce elementary particles.
We
start with a description of cosmic rays and gamma rays. They collide
with atoms in the atmosphere to create a wide variety of particles. We
cover how cloud chambers work to ‘see’ these new particles. That
includes taking a look at the tracks for electrons and protons. We then
take a look at the new particles we found on mountain tops and up in
balloons: positrons, electron-positron pair creation, muons; pions;
kaons; and particle decay timing and signatures.
We then cover
the hard to find neutrino, starting with the Ellis - Wooster experiment
to measure the energy of radium decay into polonium that lead to
Wolfgang Pauli’s 1927 prediction that the existence of the neutrino. We
then take a look at the 1970 bubble chamber track that first detected
it.
Next we probe the proton using scattering experiments like
the ones used by Rutherford to probe the nucleus. This time we use
electrons instead of alpha particles. We cover how this was done at the
Stanford Linear Accelerator Center (SLAC) in 1969. We show how particle
acceleration is accomplished, and how particle detection is done with
hodoscopes and calorimeters. We also examine the test results,
explaining the idea of ‘cross section’ measurements as a way to identify
scattering target sizes. We end with the results that showed that the
proton has 3 parts: now called quarks.
We then cover how quarks
form hadrons (baryons and mesons) with their predicted spin, charge and
mass. With these predictions, the hunt for these particles went into
high gear. We cover the discovery of the lambda, xi, and omega particles
that show that the quark theory was correct.
We end with a
review of particle sizes we’ve seen so far from the atom to the
neutrino. We also show how this large array of new particles begins to
fit into a model organized around particle masses (leptons and hadrons)
and particle spins (fermions and bosons) along with their different
statistical behaviors in a group.
STEM
In this segment of our “How small is it” video book, we introduce elementary particles.
We
start with a description of cosmic rays and gamma rays. They collide
with atoms in the atmosphere to create a wide variety of particles. We
cover how cloud chambers work to ‘see’ these new particles. That
includes taking a look at the tracks for electrons and protons. We then
take a look at the new particles we found on mountain tops and up in
balloons: positrons, electron-positron pair creation, muons; pions;
kaons; and particle decay timing and signatures.
We then cover
the hard to find neutrino, starting with the Ellis - Wooster experiment
to measure the energy of radium decay into polonium that lead to
Wolfgang Pauli’s 1927 prediction that the existence of the neutrino. We
then take a look at the 1970 bubble chamber track that first detected
it.
Next we probe the proton using scattering experiments like
the ones used by Rutherford to probe the nucleus. This time we use
electrons instead of alpha particles. We cover how this was done at the
Stanford Linear Accelerator Center (SLAC) in 1969. We show how particle
acceleration is accomplished, and how particle detection is done with
hodoscopes and calorimeters. We also examine the test results,
explaining the idea of ‘cross section’ measurements as a way to identify
scattering target sizes. We end with the results that showed that the
proton has 3 parts: now called quarks.
We then cover how quarks
form hadrons (baryons and mesons) with their predicted spin, charge and
mass. With these predictions, the hunt for these particles went into
high gear. We cover the discovery of the lambda, xi, and omega particles
that show that the quark theory was correct.
We end with a
review of particle sizes we’ve seen so far from the atom to the
neutrino. We also show how this large array of new particles begins to
fit into a model organized around particle masses (leptons and hadrons)
and particle spins (fermions and bosons) along with their different
statistical behaviors in a group.
STEM
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