England · Waves · Unit WA-U4

Optics and radiation

A proposed unit with 3 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-U4 · Optics and radiation

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WA-12 · WA-U4 · Planned

Lenses and image formation

  • ScopeSeparate Physics
  • Difficulty3 / 4 · proposed
  • Time35–40 min · estimated
  • StatusPlanned

Learning objectives

Construct convex/concave lens ray diagrams; distinguish real/virtual images; calculate magnification.

8463 §§4.6.2.5 / No Trilogy counterpart

DfE single-science pp.37–39 / Combined pp.32–33. Evidence checked 30 September–1 October 2026. Skills: WS1.2; MS3b,3c,5a,5c.

Needs firstWA-05

Explanation

A lens changes ray direction through refraction. Convex lenses can form real or virtual images depending on object position; a concave lens forms a virtual image. Magnification is a ratio, so object and image heights use the same units and the answer has no unit.

Concepts, equations and units: Magnification=image height/object height, no unit; both heights same units; principal focus, focal length m; convex real or virtual, concave virtual.

Prediction, demonstration and game exercise

Predict, observe, explain

Move an object through focal positions and show screen capture versus virtual viewing.

Planned learner game exercise

Position lenses to make a specified image; place principal rays and predict size/orientation before reveal.

Independent practice

Three ray-diagram cases and two magnification calculations.

Original practice example · Separate Physics

An image is 30 mm high and its object is 10 mm high. Find magnification.

Show working and model answer

Working / reasoning

Magnification = image height/object height = 30/10.

Answer

3, with no unit.

Exit check and success criteria

Correct image type/orientation for two cases and both ratios correct without units.

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 lens images can be caught on a screen; magnification is measured in cm; ray lines are physical tracks.

Practical preparation

Optional lens/magnification investigation, AT4,8; not an additional 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 →

WA-13 · WA-U4 · Planned

Visible colour, filters and reflection

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

Learning objectives

Explain opaque colour and filters through selective absorption/reflection/transmission; distinguish specular/diffuse reflection and transparent/translucent.

8463 §§4.6.2.6 / 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; MS5b.

Needs firstWA-08,WA-04

Explanation

An opaque object’s appearance depends on incident wavelengths and which it reflects. Filters selectively transmit and absorb; they do not manufacture missing light. Rough surfaces reflect at many local orientations, producing diffuse reflection while each local ray obeys the reflection rule.

Concepts, equations and units: Visible wavelength bands; no new equation; source spectrum matters.

Prediction, demonstration and game exercise

Predict, observe, explain

Illuminate coloured objects with white and single-colour light; show rough/smooth reflected rays.

Planned learner game exercise

Select light/filter combinations to reveal a coded object; predict black appearances when available light is absorbed.

Independent practice

Explain three source–filter–object cases and draw smooth/rough ray patterns.

Original practice example · Separate Physics

An ideal red-reflecting object is lit only by blue light, which it absorbs. How does it appear?

Show working and model answer

Working / reasoning

No red light is incident to reflect, and the supplied blue light is absorbed.

Answer

Black or very dark in the ideal model.

Exit check and success criteria

Two colour predictions correct with wavelength explanation and both reflection patterns consistent.

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

A red object always looks red; filters add their colour; diffuse rays violate reflection law.

Practical preparation

Optional colour/filter investigation, 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-14 · WA-U4 · Planned

Black bodies and radiation balance

  • ScopeSeparate Physics + Separate Physics Higher balance
  • Difficulty3 (H 4) / 4 · proposed
  • Time35–40 min · estimated
  • StatusPlanned

Learning objectives

Explain emission at all temperatures and temperature-dependent spectrum; H: relate temperature change to absorbed/emitted power, including Earth.

8463 §§4.6.3.1–4.6.3.2 / No Trilogy counterpart

DfE single-science pp.37–39 / Combined pp.32–33. Evidence checked 30 September–1 October 2026. Skills: WS1.2,1.3,3.5; MS4a.

Needs firstWA-11,EN-03

Explanation

Every object emits radiation, and emission distribution changes with temperature. A perfect black body absorbs all incident radiation and is the best emitter. The Higher energy-balance branch distinguishes absorbed power from incident/reflected power and links net absorption to temperature change.

Concepts, equations and units: Perfect black body absorbs all incident radiation and is best emitter; spectrum intensity/wavelength vs temperature; H power balance W.

Prediction, demonstration and game exercise

Predict, observe, explain

Compare labelled model spectra; H vary absorption/reflection/emission of Earth–atmosphere model.

Planned learner game exercise

Choose surfaces for a satellite; H adjust incoming/absorbed/emitted power and predict warming/cooling/equilibrium.

Independent practice

Interpret two spectra; H annotate an Earth radiation diagram and identify a model limitation.

Original practice example · Separate Physics Higher

A body absorbs 120 W and emits 100 W, with no other transfers in the stated model. Predict its temperature change.

Show working and model answer

Working / reasoning

Net rate into the body = 120 − 100 = 20 W; internal energy rises.

Answer

It warms; net absorbed power is 20 W.

Exit check and success criteria

Correct hotter-spectrum comparison; H temperature change consistent with net absorbed power and equilibrium rates equal.

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

Cold objects do not radiate; constant temperature means no transfer; greenhouse model proves exact future temperature.

Practical preparation

RP-P10 data revisit; black-body theory and H balance extend beyond shared 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.