Which of the following explains why a thick glass cup cracks when boiling water is poured into it?
Answer Details
The correct option that explains why a thick glass cup cracks when boiling water is poured into it is "Unequal expansion of the exterior and interior walls of the cup." When boiling water is poured into a glass cup, the temperature of the cup increases rapidly. The outer layer of the cup expands due to the sudden increase in temperature while the inner layer remains cooler. Since the outer layer of the cup is hotter than the inner layer, it expands more than the inner layer. This uneven expansion causes stress on the glass, which may exceed its strength and cause it to crack or break. Therefore, the unequal expansion of the exterior and interior walls of the cup is the reason why it cracks when boiling water is poured into it.