Why do thick glass tumblers break on pouring hot water more often than thin glass tumblers ?
Solution. Posted on Thursday, December 11, 2014.
In fact, glass is a poor conductor of heat and it is a fairly good thermal insulator. So, when we pour hot water, the inside of the glass gets heated immediately because it comes into straight contact with hot water. The outside of the glass remains at a lower temperature as the heat conducts through the glass slowly. The thicker the glass is, the greater temperature difference between its outer and inner surfaces. Finally, the inner layer expands more than the outer layer and it leads to cracking.