LuduminaWA-05 · WA-U2 · Planned
Refraction and wavefronts
Learning objectives
Draw refraction rays at a boundary; H: explain bending using speed change and wavefronts.
8463 §§4.6.2.2;8.2.9 / 8464 §§6.6.2.2
DfE single-science pp.37–39 / Combined pp.32–33. Evidence checked 30 September–1 October 2026. Skills: WS1.2,2.6; MS5a,5b.
Explanation
A refracted ray changes direction when it crosses obliquely into a medium with different wave speed. Toward-normal bending occurs on slowing; away-normal on speeding. Frequency remains set by the source. Higher explanation relates the turning wavefront to different speeds at the boundary.
Concepts, equations and units: Ray angles from normal; frequency unchanged across boundary; v=fλ; speed/wavelength change; no Snell-law calculation required.
Prediction, demonstration and game exercise
Predict, observe, explain
Predict air-to-glass bending, including normal incidence; H: turn wavefronts as speed changes.
Planned learner game exercise
Place blocks/prisms and trace beams; H: select a consistent speed/wavelength wavefront model.
Independent practice
Two ray diagrams; H explanation; P compare reflection/refraction measurements from different substances.
Original practice example · Shared
Light enters slower glass from air at an oblique angle. Describe bending and the frequency change.
Show working and model answer
Working / reasoning
Slower propagation makes the ray bend toward the normal; frequency remains the same while wavelength decreases.
Answer
Toward normal; unchanged frequency.
Exit check and success criteria
Correct toward/away-normal rays for supplied speed changes; H preserves frequency and explains bending.
During practice, compare the prediction with evidence and give an error-specific prompt. The exit item uses a fresh context or fresh values, answered independently.
Misconceptions, practical links and mastery
Check these misconceptions
All refraction bends toward normal; frequency changes at boundary; refraction absent from Combined Science.
Practical preparation
RP-P9 refraction part only. Shared refraction theory has no equivalent Trilogy optics RP; AT4,8 for P.
Virtual preparation and revision only. Required hands-on activities and school records remain separate.
Proposed mastery
0: not yet evidenced. 1: supported. 2: independent exit criteria met. 3: successful changed-context transfer. Advance at 2; revisit with fresh retrieval. These are not GCSE grades.