LuduminaEL-03 · EL-U1 · Planned
Investigating resistance
Learning objectives
Plan both wire-length resistance and series/parallel resistor comparisons; evaluate heating and measurement limits.
8463 §§4.2.1.3;8.2.3 / 8464 §§6.2.1.3;10.2.15
DfE single-science pp.39–41 / Combined pp.33–34. Evidence checked 30 September–1 October 2026. Skills: WS2.1–2.7,3.4–3.7; MS2a,2b,3c,4c,4d.
Needs firstEL-02
Explanation
A longer uniform wire has greater resistance when material, cross-section and temperature stay fixed. Measurement leads and contacts can add an offset. Resistance practical preparation must also test resistor combinations in series and parallel, not only wire length.
Concepts, equations and units: R=V/I; Ω; wire length m; fixed material, cross-section and temperature; equivalent resistance.
Prediction, demonstration and game exercise
Predict, observe, explain
Use a ruler, wire, meters and controlled low current; compare series/parallel fixed resistors.
Planned learner game exercise
Collect repeated resistance-versus-length readings then test resistor combinations with a checked schematic.
Independent practice
Graph R–length, find gradient/intercept, explain contact/lead resistance and heating bias.
Original practice example · Shared
Wire readings are 0.50 V and 0.10 A. Find resistance. Name a control for comparing lengths.
Show working and model answer
Working / reasoning
R = 0.50/0.10 = 5.0 Ω. Keep temperature, material and cross-sectional area fixed.
Answer
5.0 Ω; temperature is one valid control.
Exit check and success criteria
Valid plans for both specified parts, correct R values and one justified improvement for each.
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
The practical requires only wire length; low resistance means safe at arbitrary current; repeat readings remove systematic error.
Practical preparation
RP-P3/RP-C15, both (a) wire length and (b) series/parallel resistor circuits; AT1,6,7.
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.