Advanced Science Primary 4 Energy

Why are there small gaps left between the metal tracks of a railway line?

A To save material during construction.
B To allow the train to move faster.
C To allow the tracks to expand on a hot day without buckling.
D To let rainwater drain through.
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Worked Solution

Step 1: Metals expand when they gain heat. Step 2: On a hot day, the tracks will increase in length. Step 3: The gaps provide space for this expansion so the tracks do not bend or buckle.

Correct answer: To allow the tracks to expand on a hot day without buckling.

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