England · Waves · Unit WA-U2

Interfaces and sound

A proposed unit with 4 lectures, independent practice and a unit assessment.

Unit scope

Filters show lectures with relevant core content. Mixed lectures retain clearly labelled Higher/separate extensions; those extensions are not required on other routes. Difficulty is a design rating, not a GCSE grade.

Lectures

WA-U2 · Interfaces and sound

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WA-04 · WA-U2 · Planned

Reflection and material interfaces

  • ScopeSeparate Physics
  • Difficulty2 / 4 · proposed
  • Time30–35 min · estimated
  • StatusPlanned

Learning objectives

Draw reflection rays and normal; distinguish reflected, transmitted and absorbed energy.

8463 §§4.6.1.3 / No Trilogy counterpart

DfE single-science pp.37–39 / Combined pp.32–33. Evidence checked 30 September–1 October 2026. Skills: WS1.2,2.6; MS5a,5c.

Needs firstWA-01,WA-02

Explanation

The normal is perpendicular to the surface at the point of incidence. Reflection angles are measured from that normal. At a material boundary, incident energy may be divided between reflection, transmission and absorption rather than all reflected.

Concepts, equations and units: Angles from normal in degrees; incidence angle=reflection angle; ray and wavefront representations differ.

Prediction, demonstration and game exercise

Predict, observe, explain

Send waves to a boundary and compare smooth/rough surfaces; annotate energy partitions.

Planned learner game exercise

Orient mirrors to send a beam to a receiver; compare reflective and absorbing materials.

Independent practice

Two ray-diagram problems and an interface explanation; record angles in a table.

Original practice example · Separate Physics

A ray arrives at 35° to the normal of a mirror. State its reflection angle.

Show working and model answer

Working / reasoning

For reflection, angle of incidence equals angle of reflection, both measured from the normal.

Answer

35° to the normal.

Exit check and success criteria

Both ray constructions within 2° target tolerance and all three outcomes distinguished.

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

Angles measured from surface; every boundary reflects all incident energy; diffuse reflection breaks reflection law.

Practical preparation

RP-P9 reflection part; AT4,8.

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.

Full lecture page →

WA-05 · WA-U2 · Planned

Refraction and wavefronts

  • ScopeShared + Higher explanation; Separate Physics practical
  • Difficulty3 / 4 · proposed
  • Time30–35 min · estimated
  • StatusPlanned

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.

Needs firstWA-02; WA-04 for P

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.

Full lecture page →

WA-06 · WA-U2 · Planned

Sound, hearing and transmission

  • ScopeSeparate Physics + Separate Physics Higher hearing
  • Difficulty3 / 4 · proposed
  • Time30–35 min · estimated
  • StatusPlanned

Learning objectives

Relate sound speed, frequency and wavelength across media; H: explain sound-to-solid vibration and hearing limits.

8463 §§4.6.1.2,4.6.1.4 / No Trilogy counterpart

DfE single-science pp.37–39 / Combined pp.32–33. Evidence checked 30 September–1 October 2026. Skills: WS1.2,3.6; MS1c,3c.

Needs firstWA-01–03

Explanation

Sound needs a material whose disturbances can propagate. At a boundary, source frequency is preserved but speed and wavelength can change. On the separate Higher route, hearing is explained by sound causing vibrations in solids in the ear over a limited frequency range.

Concepts, equations and units: v=fλ; m/s,Hz,m; frequency fixed by source; H normal human hearing about 20 Hz–20 kHz.

Prediction, demonstration and game exercise

Predict, observe, explain

Transmit a model tone into another medium; H: show eardrum vibration within a limited response range.

Planned learner game exercise

Match source-frequency and wavelength cards in two media; H: classify audible/ultrasound tones using numbers, not real loud audio.

Independent practice

Two wavelength comparisons; H explain ear response and why sound needs matter.

Original practice example · Separate Physics

A 1000 Hz sound wave travels at 1500 m/s in a supplied medium. Find wavelength.

Show working and model answer

Working / reasoning

λ = v/f = 1500/1000.

Answer

1.5 m.

Exit check and success criteria

Frequency preserved with correct wavelength changes; H correct hearing range and vibration chain.

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

Pitch always changes between media; humans hear every frequency; animation scale is a real ear motion measurement.

Practical preparation

Optional sound transmission demonstration; AT4,8; no required practical specific to hearing.

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.

Full lecture page →

WA-07 · WA-U2 · Planned

Ultrasound, sonar and seismic evidence

  • ScopeSeparate Physics Higher
  • Difficulty4 / 4 · proposed
  • Time35–40 min · estimated
  • StatusPlanned

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.

Full lecture page →

Area capstone

Sources and full programme

Sources checked 30 September–1 October 2026. Specifications govern content; textbooks supplement it. England has no single prescribed Physics course book. The full planning document includes sourced comparisons of Collins separate Physics and Trilogy books, Hodder/Hachette Physics and Oxford Physics listings, with access/approval limitations.

Download the complete Markdown programme and coverage matrix

A subsection map is proposed coverage. Clause-level educator review, item moderation, model validation and hands-on provision remain release gates. No all-board alignment or exam-board endorsement is claimed.