Safety boundary
Use simulations, printed optics, and eye-safe light only. Do not direct lasers or intense light at people.
Explicit physics instruction
Reflection follows equal incident and reflected angles measured from the normal in the ideal ray model.
Refraction occurs because wave speed changes between media, changing wavelength and often direction.
Ray diagrams are geometric models that approximate wave behavior when dimensions are large compared with wavelength.
Vocabulary: reflection; refraction; normal; refractive index; ray model.
Worked example
A ray striking a mirror at 30° from the normal reflects at 30° on the other side of the normal.
Guided question
Why can light bend when entering a material even though its frequency stays fixed?
Independent work
- Draw three reflection/refraction ray diagrams.
- Identify normal and angles.
- Explain one limit of the ray model.
Misconception check
Angles are measured from the normal, not from the surface.
Formative check
What quantity stays fixed across a boundary for a wave driven by the same source?
Reveal response
Frequency.
Mentor evidence conference
Ask Archaemenes to audit wave variables, encoding assumptions, metrics, and model limits.
Teacher guidance
Foundation: Use ray templates.
Core: Analyze reflection/refraction qualitatively.
Extended: Compare ray and wave-model limits.