Standard Science Primary 5 Cycles

Siti placed two identical mirrors, Mirror A and Mirror B, in a warm bathroom after a hot shower. She wiped Mirror B so that it was completely dry, but left Mirror A wet. Which mirror will form more "fog" (water droplets)?

A Mirror B
B Both will form the same amount.
C Mirror A
D Neither will form fog.
Show Worked Solution

Worked Solution

Step 1: "Fog" on a mirror is caused by condensation of warm water vapour onto a cooler surface. Step 2: For condensation to happen effectively, the warm water vapour needs to come into contact with the cooler surface of the mirror. Step 3: Mirror B provides a dry, cool surface for the water vapour to lose heat and condense.

Correct answer: Mirror B

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