PSLE Science • Energy • Elastic systems
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Trace energy into a compressed or stretched spring, through storage, and out through motion and other transfers.
A deformed spring stores elastic potential energy transferred into it by work. On release, it transfers energy; it does not create energy.
Reading route
- Define the problem
- Learn the mechanism
- Study examples
- Repair misconceptions
- Practise
- Transfer
- Exam control
Use the complete volume directory, original PSLE Learning Guide, and Science hub.
The problem: seeing motion after release and assuming the spring made energy
A spring can make a car move, a button return or a toy jump. Because the motion begins when the spring is released, a learner may say that the spring created energy at that moment.
The missing part is the input. A hand, motor or winding mechanism did work while compressing or stretching the spring. Energy was transferred into the deformed spring and stored as elastic potential energy.
On release, the stored energy transfers into movement and other forms. Sound, vibration and thermal energy from friction explain why not all input appears as the desired motion.
The mechanism: input, elastic storage, release and losses
1. System and deformation
Identify the spring, the object applying force, and whether the spring is compressed or stretched. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
2. Energy input
Work done by a hand or mechanism transfers energy into the deformed spring. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
3. Elastic store
Within its elastic behaviour, the spring stores elastic potential energy while held away from its usual shape. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
4. Release transfer
When released, stored energy transfers to movement and may also become sound or thermal energy. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
5. No energy creation
The spring does not create energy; its output traces back to input work. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
6. Elastic return
A useful spring returns toward its original form, but excessive deformation can cause permanent change. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
7. Fair comparison
Compare the same spring, starting position, load and release method when testing different deformation amounts. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
8. Evidence and limits
Distance moved, height reached or speed can indicate energy transfer, but friction and air resistance affect outcomes. Begin the explanation before release, not at the first visible movement.
Draw an energy chain with arrows and name the object or process at each stage. This prevents vague statements such as “the spring has force” from replacing energy reasoning.
Use evidence cautiously. Greater distance or height can support greater energy transfer only when mass, surface, spring, starting point and release method are controlled.
State the boundary: real systems also transfer energy to sound and thermal stores, and extreme deformation may damage the spring rather than behave elastically.
Worked examples: trace every transfer
Worked example 1: Toy launcher
Situation. A compressed spring launches a toy car.
Energy account. Hand work becomes stored elastic energy, then car movement. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 2: Pen spring
Situation. A pen spring pushes the button back.
Energy account. Compression stores energy that is released on return. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 3: Stretched spring
Situation. A stretched spring pulls a cart when released.
Energy account. Stretching can store elastic potential energy too. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 4: Held spring
Situation. A spring is compressed and held still.
Energy account. No visible motion occurs, but energy is stored. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 5: Release sound
Situation. A released spring vibrates and makes sound.
Energy account. Some transferred energy appears as sound, not only useful motion. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 6: Friction
Situation. The same release moves a cart less on rough ground.
Energy account. More energy transfers thermally through friction. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 7: Greater compression
Situation. The same spring is compressed farther within safe range.
Energy account. More input work can lead to more stored energy. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 8: Different springs
Situation. A stiff and soft spring are compressed equally.
Energy account. Equal distance alone does not guarantee equal stored energy. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 9: Permanent bend
Situation. A spring stays distorted after extreme stretching.
Energy account. It has exceeded ordinary elastic behaviour. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 10: Height test
Situation. A spring launches the same mass to different heights.
Energy account. Height is evidence for different energy transfer when controls are fair. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 11: Mass change
Situation. A heavier cart moves less far from the same setup.
Energy account. Changing mass prevents a simple compression-only comparison. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Worked example 12: Energy chain
Situation. A wind-up toy uses a spring.
Energy account. Human work stores energy; release transfers it through the mechanism. Name the input agent, stored energy and observed output.
Before release, deformation is evidence that work has been done. While held, the system can contain stored energy even though speed is zero. After release, decreasing deformation accompanies transfer out of the spring.
A common error starts the story at motion and says energy appeared. Repair it by tracing backward to the work that compressed, stretched or wound the spring.
For transfer, change one control such as surface, mass or spring. Predict which observed outcome can change and why the comparison no longer isolates deformation alone.
Finish with a conservation check: useful motion plus sound, vibration and thermal transfers must be accounted for rather than treated as missing energy.
Misconception clinic
Repair 1: The spring creates energy
Trace energy back to input work. Ask the learner to draw the chain before writing prose.
Use a minimal pair where one control changes. Explain why the outcome alone cannot identify the cause when several variables differ.
Repair 2: No motion means no energy
A held deformation can store potential energy. Ask the learner to draw the chain before writing prose.
Use a minimal pair where one control changes. Explain why the outcome alone cannot identify the cause when several variables differ.
Repair 3: All energy becomes useful motion
Include sound and thermal transfers. Ask the learner to draw the chain before writing prose.
Use a minimal pair where one control changes. Explain why the outcome alone cannot identify the cause when several variables differ.
Repair 4: Only compression stores energy
Stretching can also store elastic energy. Ask the learner to draw the chain before writing prose.
Use a minimal pair where one control changes. Explain why the outcome alone cannot identify the cause when several variables differ.
Repair 5: More compression always means safe improvement
Stay within elastic limits. Ask the learner to draw the chain before writing prose.
Use a minimal pair where one control changes. Explain why the outcome alone cannot identify the cause when several variables differ.
Repair 6: Equal distance makes a fair test
Control spring, mass, surface and release. Ask the learner to draw the chain before writing prose.
Use a minimal pair where one control changes. Explain why the outcome alone cannot identify the cause when several variables differ.
Graded independent practice
Questions
- What energy is stored in a compressed spring?
- Where did that energy come from?
- Does a held compressed spring have energy?
- What happens on release?
- Can a spring create energy?
- Why can rough ground shorten travel?
- Can a stretched spring store energy?
- Why use the same cart in a fair test?
- Does equal compression of different springs guarantee equal energy?
- What shows permanent deformation?
- Name one measured outcome.
- Give a three-step chain.
Explained answers
1. Elastic potential energy. Check that the answer includes input, storage, release and any relevant losses or controls.
2. Work done by the hand or mechanism. Check that the answer includes input, storage, release and any relevant losses or controls.
3. Yes, even without visible motion. Check that the answer includes input, storage, release and any relevant losses or controls.
4. Stored energy transfers to kinetic energy and possibly sound and thermal energy. Check that the answer includes input, storage, release and any relevant losses or controls.
5. No. Check that the answer includes input, storage, release and any relevant losses or controls.
6. Friction transfers more energy thermally. Check that the answer includes input, storage, release and any relevant losses or controls.
7. Yes, if it is elastically deformed. Check that the answer includes input, storage, release and any relevant losses or controls.
8. Mass and wheel differences could change motion. Check that the answer includes input, storage, release and any relevant losses or controls.
9. No; spring properties differ. Check that the answer includes input, storage, release and any relevant losses or controls.
10. The spring fails to return to its original form. Check that the answer includes input, storage, release and any relevant losses or controls.
11. Distance, speed or launch height under controlled conditions. Check that the answer includes input, storage, release and any relevant losses or controls.
12. Input work → elastic potential energy → movement plus other transfers. Check that the answer includes input, storage, release and any relevant losses or controls.
Delayed transfer
Transfer 1
Compare a spring toy on smooth and rough surfaces. Predict the outcome before testing and identify every variable that should remain fixed.
After a delay, reconstruct the chain without notes. If the explanation begins at release, add the missing input stage.
Transfer 2
Design a fair test of two compression distances. Predict the outcome before testing and identify every variable that should remain fixed.
After a delay, reconstruct the chain without notes. If the explanation begins at release, add the missing input stage.
Transfer 3
Explain a stretched elastic cord using the same energy chain. Predict the outcome before testing and identify every variable that should remain fixed.
After a delay, reconstruct the chain without notes. If the explanation begins at release, add the missing input stage.
Transfer 4
Diagnose a spring that no longer returns to shape. Predict the outcome before testing and identify every variable that should remain fixed.
After a delay, reconstruct the chain without notes. If the explanation begins at release, add the missing input stage.
Transfer 5
Compare a held compressed spring with a moving released spring. Predict the outcome before testing and identify every variable that should remain fixed.
After a delay, reconstruct the chain without notes. If the explanation begins at release, add the missing input stage.
Synthesis laboratory
Synthesis case 1: Toy launcher
For a compressed spring launches a toy car., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 2: Pen spring
For a pen spring pushes the button back., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 3: Stretched spring
For a stretched spring pulls a cart when released., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 4: Held spring
For a spring is compressed and held still., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 5: Release sound
For a released spring vibrates and makes sound., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 6: Friction
For the same release moves a cart less on rough ground., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 7: Greater compression
For the same spring is compressed farther within safe range., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 8: Different springs
For a stiff and soft spring are compressed equally., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 9: Permanent bend
For a spring stays distorted after extreme stretching., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 10: Height test
For a spring launches the same mass to different heights., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 11: Mass change
For a heavier cart moves less far from the same setup., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Synthesis case 12: Energy chain
For a wind-up toy uses a spring., write a complete before-during-after energy narrative. Before release, name who or what does work. During storage, identify the deformed spring. After release, separate useful movement from sound, vibration and heating.
Create a rival explanation that says energy was created, then refute it by pointing to the earlier work. Add one fair-test control and one limitation. This turns a label into a causal account that can survive a changed apparatus.
Examination control
- Identify the spring and deformation.
- Name the input work.
- State elastic potential energy storage.
- Trace release to movement.
- Include sound or thermal transfers where relevant.
- Check fair-test controls and elastic limits.
A concise response can say: “Work done compressing the spring transfers energy into its elastic store. When released, the spring transfers this energy to the car’s movement, with some energy also transferred as sound and heat.”
Do not write that force is stored or that energy is used up. Force describes an interaction; energy is transferred and conserved.
Advice for parents and tutors
Ask learners to tell the story backward from motion to the hand that compressed the spring. Backward tracing often reveals the missing input.
Use the same apparatus for comparisons and change only one variable. Let the learner name controls before the trial.
Return after a day with a pen, toy or elastic cord to test transfer.
Frequently asked questions
What is stored?
Elastic potential energy.
Can a still spring have energy?
Yes, while deformed and held.
Where did it come from?
Work done by a hand or mechanism.
What happens on release?
Energy transfers to movement and other forms.
Is energy lost?
It is transferred, often including sound and thermal energy.
Can stretching store energy?
Yes, within elastic behaviour.
Can a spring be damaged?
Yes, excessive deformation can be permanent.
Fastest check?
Trace input, store, release and outputs.
Next routes
Return to the directory, foundation guide, or Science hub.