Standard Science Primary 4 Energy

Siti found it difficult to open the metal lid of a glass jar. She poured hot water over the metal lid and was then able to open it easily. Why?

A The glass jar expanded more than the metal lid.
B The hot water acted as a lubricant.
C The metal lid expanded and became looser.
D The metal lid contracted when heated.
Show Worked Solution

Worked Solution

Step 1: Metal gains heat from the hot water. Step 2: Metals expand when they gain heat. Step 3: The expansion makes the lid slightly larger/looser, making it easier to twist.

Correct answer: The metal lid expanded and became looser.

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

Start Free Trial — 7 Days Free