How to Perform in PSLE | Learner’s Guide Vol 0967 | Science: A Shadow Shows Blocked Light, Not the Colour of the Opaque Object

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1. Define the shadow by light

A shadow forms where an object prevents some light from reaching a surface. The dark or dim region belongs to the illuminated surface, not to a coloured substance transferred from the object.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

• Check the light source object and receiving surface.
• Check the straight-line paths that are blocked or remain open.
• Check the illumination reaching each region.
• Check source size colour surface reflectivity distance and evidence limits.

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2. Separate object colour from blocking

A red card and a blue card with the same opaque shape can cast similar shadows under the same light because both block the relevant rays. Their visible colours come from reflected light from their surfaces.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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3. Track source object and screen

A complete explanation names the source, the blocking object and the screen or ground where illumination is reduced. Leaving out the receiving surface makes the mechanism incomplete.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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4. Use straight-line paths

In the simple ray model, light travels in straight lines. Draw boundary rays from the source past the object edges to locate the shadow rather than colouring around the object by guesswork.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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5. Explain coloured illumination

Under coloured light, the lit surface may appear coloured while the fully shadowed region receives little or none of that source light. Its appearance still depends on other ambient light and the surface.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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6. Distinguish full and partial shadow

An extended source can create a central region where the source is fully blocked and a surrounding region where only part is blocked. These differences arise from source geometry, not object paint.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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7. Control comparison conditions

To test whether object colour changes a shadow, keep shape, size, position, opacity, source and screen fixed while changing only surface colour.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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8. Limit the claim to observation

A photograph of a shadow can show outline, position and relative darkness under stated lighting. It does not by itself reveal the hidden object’s colour or material.

Build the explanation by naming the light source object and receiving surface and the straight-line paths that are blocked or remain open. A remembered keyword is not enough: connect the observation to the mechanism and identify what would have to change for the conclusion to change.

Repair the nearest misconception by checking the illumination reaching each region and returning to source size colour surface reflectivity distance and evidence limits. State why the tempting alternative is too strong, incomplete or about a different stage.

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CHAPTER 9 OF 12 · Back to contents

9. Worked examples

Worked case 1: A red card casts a dark region on white paper. What creates the region?

Controlled answer. The card blocks light from reaching that part of the paper. The shadow is reduced illumination on the paper.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Replace the card with an equally opaque blue one. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “The card blocks light from reaching that part of the paper” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 2: Can shadow colour identify object colour?

Controlled answer. No. Different coloured opaque objects can block the same light paths.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Name evidence needed to see object colour. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “No” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 3: What three parts should a shadow explanation name?

Controlled answer. Light source, blocking object and receiving surface. Their positions determine which rays arrive.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Draw them in order. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “Light source, blocking object and receiving surface” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 4: Why does an opaque black card not make black material travel to the screen?

Controlled answer. A shadow is caused by missing or reduced light, not transferred pigment. The screen remains the same material.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Explain using ray paths. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “A shadow is caused by missing or reduced light, not transferred pigment” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 5: Two same-shaped opaque cards, one red and one green, are tested fairly. Predict the shadow outlines.

Controlled answer. They should be the same if geometry and lighting are the same. Colour does not change the blocked boundary rays.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. State the controlled variables. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “They should be the same if geometry and lighting are the same” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 6: A transparent red sheet forms a coloured patch rather than a deep shadow. Why?

Controlled answer. It transmits selected light instead of blocking most light. The patch involves transmitted coloured light.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Compare with an opaque red card. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “It transmits selected light instead of blocking most light” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 7: A large lamp gives a fuzzy shadow edge. What is the likely reason?

Controlled answer. Different parts of the extended source are blocked differently. A partial-shadow region forms around the full shadow.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Compare with a small source. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “Different parts of the extended source are blocked differently” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 8: Does a dark shadow prove the object is black?

Controlled answer. No. Darkness shows reduced illumination, not surface colour.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Give two differently coloured blockers. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “No” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 9: What determines the shadow’s position?

Controlled answer. The relative positions of source object and receiving surface. Straight-line paths set the region that is blocked.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Move the source and predict the shift. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “The relative positions of source object and receiving surface” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 10: What determines shadow size in a simple setup?

Controlled answer. The distances and sizes of the source object and screen. Geometry changes how boundary rays spread.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Move the object toward the source. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “The distances and sizes of the source object and screen” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 11: A blue lamp illuminates white paper. What colour may the lit region appear?

Controlled answer. Blue. The paper reflects the incident blue light.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Keep the shadow explanation separate. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “Blue” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

Worked case 12: Can ambient room light make a shadow look less dark?

Controlled answer. Yes. Other light can still reach the nominal shadow region.

Mechanism. Identify the exact relationship, apply the relevant rule and preserve every stated condition. A surface clue may be compatible with several explanations, so the answer must show what makes this case decisive.

Misconception repair. Do not turn partial evidence into complete proof. Name the closest wrong answer, identify its missing condition and explain why the observed evidence supports the narrower conclusion.

Transfer. Darken the room while keeping the main source. Solve the altered case from the mechanism rather than copying the previous wording.

Reverse construction. Begin with the controlled answer “Yes” and invent a fresh prompt that would justify it for the same reason. Then change one decisive condition to create a near-nonexample. This reverse task checks whether the learner owns the boundary rather than merely recognising the original sentence.

Explanation standard. A complete explanation names the observation, connects it to the rule and limits the conclusion to what follows. It should remain valid if decorative details are removed. If the explanation depends on the story topic instead of the decisive relation, rebuild it.

Audit. Recheck the light source object and receiving surface, the straight-line paths that are blocked or remain open, the illumination reaching each region, source size colour surface reflectivity distance and evidence limits. Decide whether the evidence proves the conclusion or only supports a limited statement.

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CHAPTER 10 OF 12 · Back to contents

10. Independent practice

Practice 1: Why is the receiving surface important?

Explained answer. A visible shadow is observed as a contrast in illumination on that surface. Without a screen or ground the region may not be directly visible.

Delayed transfer. Use mist only as a separate light-path example. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 2: Repair: the red card makes a red shadow.

Explained answer. The opaque red card blocks light; its shadow does not automatically copy the card’s colour. The card’s redness comes from reflected light from the card itself.

Delayed transfer. Test with a white screen. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 3: What variable should change in a colour investigation?

Explained answer. Only the blocker’s surface colour. Shape size opacity position source and screen should remain constant.

Delayed transfer. Explain why opacity must stay fixed. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 4: Can a shadow reveal shape?

Explained answer. It can show an outline or projection under known geometry. The outline may change with orientation and distance.

Delayed transfer. Rotate the object. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 5: Can a shadow reveal material?

Explained answer. Not by itself. Many materials can be opaque and cast similar shadows.

Delayed transfer. Add an independent property test. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 6: Why use boundary rays?

Explained answer. They locate the transition between rays that reach the screen and rays blocked by the object. The method turns the geometry into a traceable explanation.

Delayed transfer. Draw from both source edges. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 7: What does a partial shadow mean?

Explained answer. Only part of an extended light source is blocked from that region. Some source light still arrives.

Delayed transfer. Contrast with full blockage. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

Practice 8: State the full explanation.

Explained answer. Light travels from the source toward the screen; the opaque object blocks selected straight-line paths, so the corresponding screen region receives less light and forms a shadow whose appearance does not copy object colour. The claim follows source path and observation.

Delayed transfer. Apply to a coloured outdoor toy. Cover the answer later and rebuild the chain.

Control question. Which exact condition does the nearest wrong answer miss? State it before checking.

Extension. Change one decisive feature while keeping the story similar. Explain why the conclusion now stays or changes.

Independent proof. Restate the answer without copying its wording. Your version must identify the evidence, the governing relationship and the boundary of the claim. Then write one fact that would be relevant but still insufficient on its own. This separates explanation from repetition.

Delayed comparison. Save this item beside the near-nonexample you created. On the next attempt, compare them before answering and point to the single feature that controls the difference. If more than one feature changed, revise the pair so the comparison stays fair.

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CHAPTER 11 OF 12 · Back to contents

11. Delayed transfer

On day one, solve clear examples. On day three, mix examples, near-nonexamples and incomplete evidence. On day seven, solve without headings or a word bank. Delay reveals whether the method can be reconstructed independently.

Keep an error log for the first failed stage: reading, representation, rule, execution or checking. The earliest failure identifies the repair.

Interleave this skill with neighbouring ideas that share vocabulary. Classify each item only after naming the distinguishing condition.

In timed work, mark the relationship, apply the rule, write the conclusion and audit one condition. If checking changes the answer, record the overlooked feature.

Create a teach-back card with a near-nonexample on the front and the repaired mechanism on the back. Explain why the tempting answer fails.

Finish with one basic example, one boundary case and one transfer case. Supply explanations that a classmate can verify.

For a second delayed test, reverse the direction: start from a conclusion and invent evidence that would justify it, then evidence that would be insufficient. This exposes the boundary between relevance and proof.

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CHAPTER 12 OF 12 · Back to contents

12. Family guidance and FAQs

Guidance for parents and tutors

Ask for the decisive condition before confirming the answer. Use prompts such as “What exactly happened?”, “Which stage or meaning is this?” and “What would prove it?”

Fade support from labelled examples to mixed questions and delayed open response. Independent retrieval after time and topic change is the target.

Praise precise claim control. Narrowing an answer when evidence is incomplete is scientific and academic strength.

Frequently asked questions

Should I memorise the rule?

Memorise the compact rule, then practise examples and near-nonexamples so the conditions remain visible.

What if two answers seem possible?

Return to the exact relationship and choose the option satisfying every stated condition without adding facts.

Why delay practice?

Immediate repetition may depend on the recent explanation; delay tests reconstruction.

How should an error be corrected?

Name the first failed stage and practise it with a changed example.

When is the skill ready?

When the learner can explain, apply and transfer it after a delay.

What is the final audit?

Check relationship, mechanism, claim strength and whole-question fit.

Next routes

Continue at the Science learning hub or return to the series directory.

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