LuduminaFM-05 · FM-U2 · Planned
Elasticity and the spring investigation
Learning objectives
Use force–extension data to estimate k; distinguish elastic/inelastic deformation and the proportionality limit.
DfE single-science pp.35–37 / Combined pp.30–32. Evidence checked 30 September–1 October 2026. Skills: WS2.2–2.7,3.5,3.7; MS3c,4c,4d.
Explanation
A spring follows F = ke only over its proportional range. Its graph can depart from a straight line before or without the same behaviour as permanent deformation. Measure extension from unloaded length and examine what happens after unloading.
Concepts, equations and units: F=ke; N, N/m, m; E_e=½ke² in proportional range; extension=loaded−original length.
Prediction, demonstration and game exercise
Predict, observe, explain
Load/unload a spring; demonstrate two forces needed to distort a stationary object and nonlinear behaviour.
Planned learner game exercise
Choose increments and repeats, collect extension data, protect the eye-line and identify a model limit.
Independent practice
Plot F against e, calculate gradient k and stored energy for a valid data point.
Original practice example · Shared
A spring extends 0.020 m under 4.0 N in its linear range. Find k.
Show working and model answer
Working / reasoning
k = F/e = 4.0/0.020.
Answer
200 N/m.
Exit check and success criteria
Correct k with units, valid range marked and justified control/improvement.
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
One force alone distorts a stationary spring; elastic limit and proportionality limit necessarily coincide.
Practical preparation
RP-P6/RP-C18; AT1,2; hands-on required at school.
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.