What Was the Question About?

Michael was cooking food wrapped in leaves over a fire. After a while, burnt marks appeared on the leaves. The MCQ asked: “Which statement best explains why the burnt marks appeared?” Let’s use some PSLE Science keywords to explain the correct answer.

Why Is Option (3) Correct?

Key Concept: Heat Transfer & Conductors

• Leaves are poor conductors of heat (i.e. they are insulators).
• Because they do not transfer heat well, heat builds up on the part of the leaf directly above the fire.
• Since the heat isn’t transferred quickly away from the surface, the leaf gets too hot and starts to burn, leaving black burn marks.

This aligns perfectly with what students learn under the topic "Heat and Temperature”: Materials that are poor conductors trap heat, while good conductors spread it quickly.

Why Are the Other Options Wrong?

• (1) The food is a poor conductor of heat → Not relevant. The question is about the leaves, not the food.
• (2) The leaves allow heat to pass through → Opposite of the correct answer. If this were true, the heat would pass through easily and not burn the leaf.
• (4) The temperature of the food is too high → Again, this doesn’t explain why the leaves are burnt. It misdirects focus to the wrong thing.

Bonus Tip: When in Doubt, Think “Material Property”

This was a classic example of how to apply conceptual knowledge rather than memorised facts. Students needed to:

• Identify what material is involved (leaves),
• Recall its property (poor conductor of heat),
• Understand the consequence (burnt marks due to heat build-up).