Light Reflection: Geometric Principles Walkthrough

Section role: supports the 'The Geometry of Reflection' section while the teacher formalizes concepts, building on student observations from Section 2. Slides: (1) Title — 'The Laws of Reflection'; (2) First Law: Incident Ray, Reflected Ray, Normal — bullets: definitions, visual diagram of rays and normal on a plane mirror; (3) Second Law: Angle of Incidence and Reflection — bullets: 'angle i = angle r', diagram illustrating the angles; (4) Spherical Mirrors: Concave and Convex — bullets: defined as parts of a hollow sphere, introduce 'Concave (converging)' and 'Convex (diverging)' with simple diagrams; (5) Key Geometric Points — bullets: define 'Centre of mirror curvature (C)', 'Pole of the mirror (p)', 'Principal axis', 'Focal length (f)', and the relationship 'f = R/2' with a combined diagram for both mirror types; (6) Rule 1: Parallel Rays — bullets: 'Rays parallel to the principal axis pass through the focus after reflection', diagram showing this for both concave and convex mirrors; (7) Rule 2: Rays Through Focus — bullets: 'Rays passing through the focus reflect parallel to the principal axis', diagram; (8) Rule 3: Rays Through C — bullets: 'Rays passing through the Centre of Curvature reflect back along the same path', diagram; (9) Summary of Ray Tracing Rules — bullets: quick recap of the three rules for sketching light paths. Concrete examples and vocabulary to surface include 'Incident ray', 'Reflected ray', 'Normal line', 'Angle of incidence', 'Angle of reflection', 'Concave mirror', 'Convex mirror', 'Pole (p)', 'Centre of Curvature (C)', 'Principal axis', 'Focal length (f)', and the 'f = R/2' relationship. This deck builds directly on the observational activities of Section 2 and sets up the application discussions in Section 4. Closing slide: 'How do these rules help us understand how mirrors form images?'

Lara from Teachy