an ordinary glass bottle cracks when boiling water is poured into it but a Borosil glass bottle does not
Answers
BcoZ borosilicate glass material expand when hot water is poured
This material expand on heating unlike others break
❖ Normal glass is an insulator which means it is a poor conductor of heat. 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. But the outer layer of the glass remains cold and does not expand (since glass is a poor conductor and does not transfer heat quickly).
❖ This difference in thermal expansion causes thermal stress which eventually leads to cracking.
❖ Borosil glasses have very low coefficients of thermal expansion which makes them resistant to thermal shock, more than any other common glass.
❖ So, Borosil glass does not crack when hot liquid is poured in it, but normal glass cracks.