Question

Why does a thick tumbler crack when hot water is poured into it? $\left[2\text{marks}\right]$
Can the tumbler also crack when very cold water is poured into it? If so, why? $\left[3\text{marks}\right]$

Answer 1

When hot water is poured into a thick glass tumbler, the inner surface of the tumbler becomes hot and expands. $\left[1\text{mark}\right]$
But the outer surface does not expand as quickly. Due to this uneven expansion, the glass tumbler cracks.
$\left[1\text{mark}\right]$
Yes, the tumbler can also crack when very cold water is poured into it. $\left[1\text{mark}\right]$
Due to very cold water, the inner surface would become cold, and then would contract, but the outer surface would not contract as quickly. So, due to this uneven contraction, the tumbler could crack. $\left[2\text{mark}\right]$