LuduminaWA-07 · WA-U2 · Planned
Ultrasound, sonar and seismic evidence
Learning objectives
Explain reflection-based hidden-structure imaging; use P/S-wave evidence for Earth’s structure.
8463 §§4.6.1.5 / No Trilogy counterpart
DfE single-science pp.37–39 / Combined pp.32–33. Evidence checked 30 September–1 October 2026. Skills: WS1.1,1.2,1.4,3.6; MS3c,4a.
Needs firstWA-06
Explanation
Reflections from internal boundaries can locate hidden structures using round-trip travel time. P and S seismic waves give different evidence: P waves traverse solids and liquids, while S waves cannot traverse liquids. Inferences depend on combining observations, not simply drawing a cutaway.
Concepts, equations and units: Round-trip distance=vt/2 as application of speed relation; ultrasound above human hearing; P longitudinal, S transverse; S cannot traverse liquid.
Prediction, demonstration and game exercise
Predict, observe, explain
Compare boundary echoes and seismic paths; separate observation from inference.
Planned learner game exercise
Locate a hidden flaw or seabed from echo times; choose an Earth model consistent with a supplied seismic dataset.
Independent practice
Two echo-distance calculations and a written P/S evidence argument.
Original practice example · Separate Physics Higher
A pulse travels at 1500 m/s and returns after 0.020 s. Find reflector distance.
Show working and model answer
Working / reasoning
One-way distance = vt/2 = 1500 × 0.020/2.
Answer
15 m.
Exit check and success criteria
Correct round-trip factor and inference consistent with both wave types; uncertainty acknowledged.
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
Ultrasound is electromagnetic; S-waves travel through liquids; images are photographs directly seen inside objects.
Practical preparation
Optional echo/supplied-data analysis; no medical diagnosis exercise or RP.
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.