Use the simulation of a Newton metre in your science or Physics class to illustrate elastic potential energy and Hooke’s law.
Newton Meter Simulation — ClassAdapt
A fully interactive 3D spring balance modelled on a real Newton meter. The physics engine runs a damped simple harmonic oscillator — when a mass is attached, the spring genuinely bounces and settles at its new equilibrium rather than jumping instantly. Every reading you see is computed, not scripted.
The 3D model comprises a semi-transparent glass-effect body tube with a cream scale face, 3D tick marks (every 0.5 N and 1 N), a red pointer that tracks the spring’s bottom in real time, a J-hook below, and a metal support rod at the top. The spring itself is a TubeGeometry rebuilt frame-by-frame as it stretches — steel blue at rest, shifting to gold near the elastic limit and red beyond it.
The tray holds ten 100 g disc weights on a shelf to the left. Students drag individual weights onto the J-hook; the spring oscillates and settles while the scale pointer moves. Weights can also be dragged back off to remove them. The +/− buttons serve as an accessible alternative for students who cannot drag.
Hooke’s Law (F = ke, k = 25 N/m) is shown live throughout:
- Each 100 g weight = 1 N; extension = F/k = 4 cm per Newton
- The red pointer on the scale gives the reading directly
- The equation card (Labels ON) shows
F = ke → 3.0 = 25 × 0.120updating in real time - The elastic limit is marked at 7 N; beyond it, the spring colour turns red and permanent deformation accumulates — the spring no longer returns to zero when masses are removed
The F-x Graph tab builds a plotted dataset as students add and remove masses. It shows the ideal Hooke’s Law dashed line, marks the elastic limit as a shaded region, and connects the student’s data points — making the linear relationship (and deviation from it beyond the elastic limit) directly visible.
Suggested Class Activity
“Does a spring always obey Hooke’s Law?”
This is the core GCSE required practical for springs, reframed around prediction, measurement, and anomaly detection.
Duration: 25–30 minutes Level: GCSE Physics / Combined Science (Y10–11) Prior knowledge: Force, extension, units of Newtons and metres
Sequence
1. Predict (4 min)
Before opening the simulation, ask students:
“If I double the force on a spring, what happens to the extension?”
Take a quick show of hands. Most will say “it doubles.” Ask: “Does this always hold, no matter how much force you add?” Collect predictions without correcting — you want genuine disagreement in the room.
2. Collect data (10 min) — individuals or pairs
Students work through the simulation methodically, adding one weight at a time and recording results in a table:
| Force F (N) | Extension x (cm) | F ÷ x (N/cm) |
|---|---|---|
| 0 | 0 | — |
| 1 | 4.0 | 25 |
| 2 | 8.0 | 25 |
| … | … | … |
| 7 | 28.0 | 25 |
| 8 | ? | ? |
Direct them: “Calculate F ÷ x for each row. What do you notice?”
The F ÷ x column stays constant up to 7 N (= the spring constant, 25 N/m) then changes — this is the elastic limit revealing itself in data before students even look at the graph.
3. Plot and interpret (6 min)
Students click the 📈 F-x Graph tab. They should now see their data points plotted. Ask:
a) “Where does the graph stop being a straight line through the origin?”
b) “What does the dashed line represent — and why do your points follow it at first?”
c) “Remove all the weights. Does the pointer return to zero? What does it mean if it doesn’t?”
The third question drives home the distinction between elastic and plastic deformation — the spring has been permanently stretched beyond its elastic limit.
4. Exam question (5 min)
Give students this mark-scheme question:
“A student hangs increasing weights on a spring and measures the extension. Describe the relationship between force and extension, and state what happens beyond the limit of proportionality.” (4 marks)
Expected answer: force and extension are directly proportional (1) up to the limit of proportionality (1); beyond this the extension increases more than expected for each additional force added (1); the spring does not return to its original length when the force is removed — permanent deformation (1).
5. Revisit predictions (3 min)
Return to the opening question. Students self-correct. The key misconception to address: Hooke’s Law only holds within the elastic region. Students who wrote “it always doubles” should articulate why they were partially right.
Adaptation notes for ClassAdapt
- Reduce Motion in the SEND panel removes spring oscillation — useful for students who find rapid movement distracting
- Extra Slow ×0.3 slows the spring bounce to about one-third speed, giving students with processing difficulties more time to observe the pointer settling
- The Labels ON eq card shows the live Hooke’s Law equation as a sentence-starter scaffold for students writing the exam question
- The elastic limit bar in the bottom strip gives a continuous visual signal of how close the spring is to permanent deformation — useful for students who find the scale hard to read
- The ± buttons are a full alternative to drag-and-drop for students with motor difficulties or on touchscreen devices without fine motor control
- For SEND students writing the table: the simulation holds its state while they write — no time pressure to record before the reading changes