LuduminaWA-14 · WA-U4 · Planned
Black bodies and radiation balance
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.
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.