Lesson Plan: The Conservation of Lepton Number Physics • 9th Grade

This lesson plan includes the objectives, prerequisites, and exclusions of the lesson teaching students how to determine the total lepton number of a set of particles and apply the conservation of lepton number to given interactions.


Students will be able to

  • recall the lepton number of all six leptons and all six antileptons,
  • recall that all of the particles that are not leptons have a lepton number of zero,
  • determine what the total lepton number of a set of leptons is before or after an interaction,
  • recall that interactions that violate the lepton number are not possible—the lepton number is conserved through all electromagnetic and weak interactions,
  • determine whether an interaction is possible or not based on whether it conserves the lepton number.


Students should already be familiar with

  • the names, basic properties, and symbols for all of the leptons and antileptons,
  • solving simple nuclear equations of beta decay.


Students will not cover

  • lepton flavor numbers,
  • neutrino oscillations,
  • quarks,
  • the strong nuclear force and strong decays,
  • supersymmetry,
  • possible fourth neutrinos—the sterile neutrino,
  • the baryon number.

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.