Why is it easier to peel when boiling eggs, soaking in cold water?

Chicken eggs include hard shells and whites, soft yolks form. Normally, after boiling, the whites and eggshell stick together, not easy to separate them. But people often boil hard-boiled eggs and drop them in cold water right away. It will be much easier to peel off the shell. What is the reason?

It turns out that the object, in general, has hot and cold properties except for a few types of matter. With different material materials, the degree of hot and cold expansion is also different. When the temperature changes a lot, the hot rhythm swells, the cold shrinks in the shell, and the egg white is uneven. When boiled at high temperatures, the eggshell is resistant to heat, egg whites are slow to transfer heat, so the degree of expansion of the eggshell is relatively large. After being submerged in cold water, the eggshell quickly again becomes cold and shrinks. And the egg white remains at the same temperature without shrinking.

At that time, a part of egg white was pressed into space by the eggshell. When the egg white due to the lower temperature shrinks, due to the decrease in volume, the egg white immediately free from adhesion to the eggshell, thereby making the eggshell very easy to peel off.