Why do thick glasses crack more easily when pouring hot water

In daily life, glassware is becoming more and more popular. Every family keeps different glassware in their house. However we know normal glass can not bear high temperature suddenly. In this situation, there is an interesting phenomenon--thick glasses crack more easily when pouring hot water. How can this happen, let me tell you !

      Generally pour boiling water into the glass, the thicker glass is more likely to burst the glass.Because the glass is cold, when the hot water is poured, the inner wall expands rapidly due to heat expansion and contraction.However, as glass is a poor conductor of heat, if the glass wall is very thick, the temperature will not be transmitted to the outer wall quickly, causing the inner wall to expand.But the outer walls remain the same, which can cause the glass to explode and shatter.

       And thinner cup, because the heat conduction is faster when pouring hot water, internal and external wall temperature difference is small, internal and external wall deformation difference is also small, so it is not easy to rupture.If you slowly pour in a small amount of water and shake the glass at the same time, making the inside and outside of the glass evenly heated, you will be better able to avoid cracking.

There are a number of factors involved in this question. A piece of thick glass placed in hot water will have the external surface heated and hence try to expand while the internal surface is not heated creating both tension and compression forces in different areas. Glass is strong in compression but not strong in tension so there is a dynamic that is resolved by the thickness and hence strength of the glass.

At the same time, hot glass break when it comes in contact with cold water. But why does this phenomenon happen ?

When cold water is poured into a hot glass, the inside of the glass quickly cools. As a result, the outside is a little longer than the inside, and the cup cannot be separated as a whole. Therefore, a huge force is generated in the inside of the cup so that making the glass break.

    In a word, we should know these phenomena and their reasons so that we can protect the glassware in daily life and use them well.