Indiana Science HS-PSII-10.1

ScienceGrades 9–12Physical Science

The Standard

Describe the Standard Model and explain the composition and decay of subatomic particles using the Standard Model and Feynman diagrams.

Indiana Academic Standards for Science (2023) · Modern Physics

Teacher's field guide

What Students Need to Do: Students identify quarks, leptons, force carriers, and the Higgs boson on a particle chart. They use quarks to build protons and neutrons, then read and draw a Feynman diagram for beta-minus decay.
What Mastery Looks Like: They label a proton uud and a neutron udd, and identify an electron as a lepton. They draw d → u + W⁻, followed by W⁻ → e⁻ + an electron antineutrino, and check that charge is conserved at each step.
Common Misconceptions: Students often think an electron was inside the neutron before it decayed. They may leave out the antineutrino or treat the W⁻ as a permanent part of the neutron. Some read diagram lines as literal travel paths.
How to Assess It: Exit ticket: Draw the quarks in a neutron, then sketch its beta-minus decay at the quark level. Label the W⁻, electron, electron antineutrino, and charge at each interaction.

Lesson moves

Give pairs up-quark and down-quark cards; have them build a neutron, change one down quark to an up quark, and add decay-product cards.
Ask: Why does beta-minus decay produce an electron if no electron was inside the neutron?
Run a diagram match: students pair four particle-interaction sketches with decay labels, then correct the sketch missing an antineutrino.
Give students the carbon-14 to nitrogen-14 decay equation used in radiocarbon dating; ask which quark changes and why the element changes.

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