Introduction
This stuck cups setup question is a common Primary Science application question on heat and expansion. Many students know that heating causes expansion and cooling causes contraction, but they get confused about which cup should be heated and which cup should be cooled. Once you apply the idea correctly, this stuck cups setup question becomes much easier to solve.
The Question / Scenario Explanation
Source: P4 Question 3
Question (as shown): Abdullah wants to separate two cups that are stuck together. Which of the following set-ups should he use to separate them?
The diagrams show four different set-ups using hot water and crushed ice around the stuck cups.
Step-by-Step Solution / Explanation
Step 1: Recall the science concept
Objects usually expand when heated and contract when cooled.
To separate two stuck cups, we want:
- the outer cup to expand
- the inner cup to contract
This is the key idea for solving the stuck cups setup question.
Step 2: Decide what should happen to each cup
The outer cup should be placed in hot water so it becomes slightly bigger.
The inner cup should be filled with crushed ice so it becomes slightly smaller.
This creates more space between the two cups and helps them separate.
Step 3: Identify the correct option
Among the four diagrams, option (4) shows:
- crushed ice inside the inner cup
- hot water around the outer cup
This is the correct stuck cups setup because the outer cup expands while the inner cup contracts.
✅ Final Answer: Option (4)
Step 4: Explain why the other options are wrong
Option (1) is wrong because it places hot water inside while crushed ice is outside. This makes the inner cup expand and the outer cup contract, which makes the cups harder to separate.
Option (2) is wrong because hot water affects both cups in a similar way, so it does not give the best separation effect.
Option (3) is wrong because crushed ice cools both cups instead of making the outer cup expand and the inner cup contract.
Only option (4) gives the correct combination for a successful stuck cups setup.
Key Concepts Students Must Know
- Materials generally expand when heated and contract when cooled.
- In a stuck cups setup, the outer object should expand and the inner object should contract.
- Hot water is used to heat the outside cup.
- Crushed ice is used to cool the inside cup.
- Science application questions often test whether students can apply a concept to a real-life situation.
Exam Tips / Common Mistakes
Exam Tips
- Ask yourself what must happen for the objects to move apart.
- For a stuck cups setup, think: outer bigger, inner smaller.
- Check carefully where the hot water is placed and where the crushed ice is placed.
- Use the science concept first before looking at the option number.
Common Mistakes
- Heating the inner cup instead of the outer cup.
- Cooling the outer cup instead of the inner cup.
- Choosing the option that uses both hot and cold without checking which cup is affected.
- Memorising “hot expands, cold contracts” but not applying it correctly in the stuck cups setup.
Parent Insight
This stuck cups setup question is a good example of how Primary Science tests understanding, not just memorisation. A child may remember that heat causes expansion, but still lose marks if they cannot apply it to the correct part of the object. Practising these real-life application questions helps students think more clearly and answer Science MCQs with greater confidence.
Conclusion
In this stuck cups setup question, the best method is to cool the inner cup with crushed ice and heat the outer cup with hot water. This makes the inner cup contract and the outer cup expand, so the cups can separate more easily. That is why the correct answer is option (4).
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