Question

When very hot water is suddenly poured into a thick glass tumbler, it sometimes cracks. Which explanation best uses the idea of thermal conductivity?

Options

• Glass conducts heat poorly, so inner part expands faster than outer

• Glass has zero thermal conductivity

• Glass contracts when heated

• Glass heats uniformly and breaks

Answer 1

Glass conducts heat poorly, so inner part expands faster than outer

Explanation:

Because glass is a poor conductor, the inner surface heats and expands faster than the outer surface, causing stress and cracking.