Standard Science Primary 4 Energy

Siti found it difficult to open a glass jar with a tight metal lid. She decided to pour hot water over the metal lid. Why did this help her open the jar?

A The hot water made the lid smoother.
B The hot water caused the glass jar to expand.
C The hot water caused the metal lid to expand.
D The hot water caused the metal lid to contract.
Show Worked Solution

Worked Solution

Step 1: Identify that the lid is tight. Step 2: Hot water provides heat energy to the metal lid. Step 3: Metal is a good conductor of heat and expands when heated. Step 4: Expansion of the lid makes it slightly larger, making it easier to unscrew.

Correct answer: The hot water caused the metal lid to expand.

Want more questions like this? Superholic Lab has 10,000+ MOE-aligned questions with full worked solutions.

Start Free Trial — 7 Days Free