Eighty years ago things were simple. The world was made of electrons, protons and neutrons. Then the muons and positrons were found in cosmic rays. Then physicists started smashing particles together and found pions, kaons and hundreds of other 'elementary' particles. The Bubble Chamber Detective lets your students understand how these 100's of particles were detected in the 1960's and '70's. This activity shows how physicists started finding patterns which led to the standard model.
Worksheet (60 minutes)
This lesson has students explore some of the conservation laws
of particle physics. It is based on Activity Five: The Rules of the Game from
the Classroom
Activities that go with the Particle
Adventure* - a resource from Lawrence Berkeley National Laboratory. The
resource has been altered slightly to highlight the similarities to and differences
from chemical reactions. The students are given information about some baryons,
mesons, leptons and protons. They are also given examples of particle events
that do and others that do not occur. From these, they can develop rules for
the conservation of charge, mass, baryon and lepton numbers. The analysis is
deepened by using the quark model and the reactions are connected with readioactivity
and cosmic rays as well as events in particle accelerators. This should be done
by students working in small groups while the teacher circulates. You will need
copies of the student
worksheet and the teacher's
notes with answers.
* The Particle Adventure is billed as "an award-winning interactive tour" but it is really just a friendly book on the computer with a few questions to answer. It is a reasonable place to send the students to for more information.
Last updated July 2010 Thanks to Tim Langford (Toronto) for reading through the excercises at making valuble suggestions for improvements.