Glasses can crack when scalded with boiling water due to the uneven expansion of the glass. When boiling water enters the cup, the inner and outer walls of the cup cannot be heated at the same time. At first, only the inner wall of the cup is heated, while the outer wall remains in a cold state, causing the inner wall part to expand rapidly, while the outer wall remains in its original shape; so the outer side will be strongly pressed by the inner side, breaking the glass. There are two anti-explosion tips for glass cups:
1. Put an iron spoon or a small stainless steel spoon in the cup, and then slowly pour boiling water into the cup. This way the cup won't burst. This is because when boiling water is poured into the bottom of the cup, the boiling water will give part of the heat to the metal teaspoon, which is a good conductor, before it has time to heat the glass (a bad conductor of heat). Therefore, the temperature of the boiling water is reduced. It changed from boiling water to hot water, which did not hinder the glass.
2. To prevent the glass from breaking, you can also boil the glass in water for 10 minutes. After such a glass is evenly heated, it will not generate strong pressure and will not cause the glass to break; or you can also put it in boiling water. Before use, put a little hot water to rinse the cup, and it will not burst when pouring hot water.