Refraction and Reflection – Ray Diagrams Simulation
What the simulation does
The simulation. A top-down optical bench for the AQA required practical on light. A ray box fires a single ray at a boundary through the centre. Pupils switch the light on, then drag the ray box up or down to change the angle of incidence. Everything updates live — the reflected ray, refracted ray, angle arcs measured from the normal, and a protractor overlay. Two modes: a plane mirror (law of reflection, angle in = angle out) and a glass block (Snell’s law, with water/perspex/diamond options, direction toggle, and total internal reflection past the critical angle). Full Adapt accessibility suite included; light/dark themes.
Suggested class activity — “Find the index” (single lesson).
- Starter (mirror): pupils set three angles, confirm angle in = angle out. Draws attention to measuring from the normal, not the surface.
- Main (glass block): record refraction angle r for i = 20, 30, 40, 50, 60°. Tabulate sin i and sin r, plot sin i against sin r, and find n from the gradient. Compare their value to 1.50.
- Extension: switch to “glass → air,” increase the angle until the refracted ray disappears — discover and measure the critical angle, then repeat for diamond and explain why diamonds sparkle.
Pairs well with a mini-whiteboard prediction round: show an angle, pupils predict r before revealing.