EL-U3 · Domestic supply and electrical energy

Unit scope

Lectures

EL-U3 · Domestic supply and electrical energy

Unit page →

EL-07 · EL-U3 · Planned

AC, mains and electrical safety

ScopeShared
Difficulty2 / 4 · proposed
Time30–35 min · estimated
StatusPlanned

Learning objectives

Distinguish AC/DC; explain live, neutral, earth and hazard protections in a supplied diagram.

8463 §§4.2.3.1–4.2.3.2 / 8464 §§6.2.3.1–6.2.3.2

DfE single-science pp.39–41 / Combined pp.33–34. Evidence checked 30 September–1 October 2026. Skills: WS1.5,3.6,4.1; MS4a.

Needs firstEL-06

Explanation

AC repeatedly reverses polarity; DC maintains one direction. Mains live conductors are dangerous relative to earth. In an earthed metal appliance, a live-to-case fault can drive a large fault current that operates protection. Diagram knowledge is not permission to handle mains.

Concepts, equations and units: UK mains about 230 V, 50 Hz AC; brown live, blue neutral, green/yellow earth; earth/neutral about 0 V; fuse and earthing.

Prediction, demonstration and game exercise

Predict, observe, explain

Use labelled diagrams and AC traces; show a live conductor can remain dangerous with a switch off.

Planned learner game exercise

Audit simulated appliances for insulation, correct wiring and earth connection; explain fault-current/fuse sequence.

Independent practice

Compare AC/DC traces and write three causal safety explanations.

Original practice example · Shared

Identify live, neutral and earth by the standard UK wire colours.

Show working and model answer

Working / reasoning

Live brown; neutral blue; earth green/yellow.

Answer

Brown live, blue neutral, green/yellow earth.

Exit check and success criteria

Three wires identified and both electric-shock and live-to-earth fault paths accurately explained.

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

Earth normally carries operating current; neutral can always be touched; a switched-off appliance is necessarily safe.

Practical preparation

Diagram-only mains activity; hands-on circuits use approved low voltage, AT7.

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.

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EL-08 · EL-U3 · Planned

Electrical work, power and appliances

ScopeShared
Difficulty3 / 4 · proposed
Time35–40 min · estimated
StatusPlanned

Learning objectives

Calculate appliance energy and power; explain p.d. as work per charge and connect chemical/electrical/thermal transfers.

8463 §§4.2.4.1–4.2.4.2 / 8464 §§6.2.4.1–6.2.4.2

DfE single-science pp.39–41 / Combined pp.33–34. Evidence checked 30 September–1 October 2026. Skills: WS1.2,4.5; MS1c,3b,3c.

Needs firstEL-02,EN-07,EN-10

Explanation

Electrical power gives energy transfer rate. Energy depends on both power and duration; charge-flow energy also depends on p.d. A battery decreases its chemical store while electrical work transfers energy to components and surroundings.

Concepts, equations and units: P=VI=I²R; E=Pt=QV; W, V, A, Ω, J, C, s; optional kWh billing context with conversion.

Prediction, demonstration and game exercise

Predict, observe, explain

Run two rated heaters for specified times; track charge flow and energy separately.

Planned learner game exercise

Select appliances and usage durations for an energy budget; calculate useful/wasted transfers.

Independent practice

Four mixed calculations including time conversion; explain battery versus mains source transfers.

Original practice example · Shared

A 12 V heater draws 2 A for 60 s. Find power and transferred energy.

Show working and model answer

Working / reasoning

P = VI = 12 × 2 = 24 W; E = Pt = 24 × 60.

Answer

24 W and 1440 J.

Exit check and success criteria

Three calculations correct and valid stores/pathways explanation for one appliance.

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

kW and kWh interchangeable; more powerful always more energy regardless of time; electron movement is the energy store.

Practical preparation

Links heater data to RP-P1/RP-C14; optional low-voltage energy measurement AT5,6.

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.

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EL-09 · EL-U3 · Planned

The National Grid

ScopeShared
Difficulty3 / 4 · proposed
Time30–35 min · estimated
StatusPlanned

Learning objectives

Explain Grid structure and qualitative roles of step-up/down transformers; connect high p.d. to reduced transfer losses.

8463 §§4.2.4.3 / 8464 §§6.2.4.3

DfE single-science pp.39–41 / Combined pp.33–34. Evidence checked 30 September–1 October 2026. Skills: WS1.4,3.6; MS3c.

Needs firstEL-08,EN-11

Explanation

The Grid links generators and consumers through cables and transformers. At the same transmitted power, higher p.d. permits lower current, reducing cable heating. Quantitative transformer ratios are a separate Physics Higher branch, while the qualitative Grid role is shared.

Concepts, equations and units: Grid: cables and transformers; high V enables lower I for same P; cable heating linked to I²R qualitatively; numerical transformer ratios reserved MG-09 P-H.

Prediction, demonstration and game exercise

Predict, observe, explain

Compare model transmission routes for fixed delivered power; distinguish distribution from energy resource.

Planned learner game exercise

Choose transformer locations and transmission p.d.; complete a system transfer map.

Independent practice

Calculate two cable powers using supplied I,R and give a three-link explanation.

Original practice example · Shared

Compare cable losses at 10 A and 5 A through the same 2 Ω cable.

Show working and model answer

Working / reasoning

P_loss = I²R: 10² × 2 = 200 W; 5² × 2 = 50 W.

Answer

200 W versus 50 W; halving current quarters loss.

Exit check and success criteria

Correct topology and high V → lower I → less heating explanation; no claim transformers create energy.

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

High voltage means more power automatically; every transformer topic is Combined Higher content.

Practical preparation

No RP; optional safe transformer demonstration by teacher.

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.