Question

A pyrex glass dish does not crack when heated strongly while on ordinary glass dish does crack. Why?

Answer 1

1. Pyrex pieces used to be made of borosilicate glass, which is more resistant to breakage when subjected to extreme shifts in temperature.
2. Normal glass is an insulator which means it is a poor conductor of heat.
3. When boiling water is poured into a glass tumbler, the surface of the glass which is in contact with the hot water heats up and expands as per its coefficient of thermal expansion.
4. That's why a pyrex glass dish does not crack when heated strongly while an ordinary glass dish does crack.