LuduminaEN-03 · EN-U1 · Planned
Conservation and dissipation
Learning objectives
Account for total energy in a closed system; explain dissipation and lubrication.
8463 §§4.1.2.1 / 8464 §§6.1.2.1
DfE single-science pp.34–35 / Combined pp.29–30. Evidence checked 30 September–1 October 2026. Skills: WS1.2,3.2,3.6; MS1c.
Needs firstEN-02
Explanation
A complete closed-system account includes the track and surrounding air, not just the cart. Friction reduces the cart’s mechanical energy while increasing internal energy elsewhere. Dissipation spreads energy into less useful stores; it does not violate conservation.
Concepts, equations and units: Energy balance in J; E_before = E_after for the specified closed system; dissipated energy remains stored less usefully.
Prediction, demonstration and game exercise
Predict, observe, explain
Predict a frictionless/frictional ramp comparison; reveal cart plus track plus surroundings accounting.
Planned learner game exercise
Run carts on selectable surfaces; complete a 100 J ledger for kinetic, thermal and other transfers.
Independent practice
Repair an incomplete Sankey-style diagram; explain the effect of lubrication.
Original practice example · Shared
A cart starts with 100 J of GPE and ends with 65 J of KE. Account for the difference in a closed cart–track–surroundings system.
Show working and model answer
Working / reasoning
100 − 65 = 35 J. Include internal energy and any other outgoing pathway destinations inside the chosen system.
Answer
35 J is redistributed into other stores, chiefly internal energy in this model; total remains 100 J.
Exit check and success criteria
Ledger totals balance and explanation names the surroundings rather than destroying 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
Wasted energy disappears; a stopped cart has no energy; conservation guarantees useful recovery.
Practical preparation
Optional ramp comparison; not an 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.