Episode 532: Preparation for particle physics topic

The first topic makes use of activities based on card sorting and arranging. The baryon, meson and lepton cards suggested here have been constructed for this project, but other excellent examples have been published, and it is well worth your considering the following:

• A resource for particle physics teaching in schools, Physics Education, March 2003, 38, p 107 with sets of online resources
• Playing with Particles – a teaching approach for A-level (post-16) particle physics, School Science Review, December 2002, 84 (307), pp 118-123

Main aims of this topic

Particles and antiparticles

Students will:

• use the terms baryon, meson, hadron and lepton
• know that, for each particle, there exists an antiparticle
• apply conservation rules to particle interactions, including particle annihilation and creation
• know that interactions between fundamental particles (quarks and leptons) are due to the exchange of other particles (vector bosons), and that these are (virtual) photons for the electromagnetic interaction and W⁺, W^- and Z⁰ particles for the weak interaction
• construct and interpret Feynman diagrams showing interactions

Prior knowledge

Students should know about the constituent particles of the atom (protons, neutrons, electrons). They should be familiar with the ideas of conservation of mass, energy and electric charge.

Where this leads

The first topic deals with the fundamental particles that students have already met, and how their number proliferated in the second half of the twentieth century. Classification of the different sorts of fundamental particles then leads to use of conserved quantities (some rather bizarre) to establish rules for particle reactions.

Students will learn that particles can be classified as hadrons – baryons and mesons – and leptons, each with its anti-particle, and they should know that interactions between these particles can be described in terms of transfer of other particles known as vector bosons.

Once the ground rules for particle interactions have been established, students can go on to learn that there is a finer level of structure to mesons and baryons.