Hot water and cold water are put in the refrigerator at the same time, which freezes first

The Mpemba effect.

It is often assumed that when a glass of cold water and a cup of hot water are placed in the refrigerator at the same time, the cold water freezes quickly. This is not the case. One day in 1963, in a middle school in Tanzania, in tropical Africa, a group of students wanted to make some frozen food to cool down.

A student named Erasto Mpemba added sugar to hot milk and prepared to put it in the fridge to make ice cream. He thought that if he waited for the hot milk to cool and put it in the refrigerator, then other students would fill the refrigerator, so he put the hot milk in the refrigerator. Soon after, he opened the refrigerator and saw that his cup of ice cream had turned into a delicious cup of ice cream, and the ice cream made by other classmates with cold water had not yet frozen.

His discovery did not attract the attention of teachers and classmates, but rather made them laugh. Mpemba told Dr. Osborne, a professor of physics at the University of Dar es Salaam, about this particular phenomenon. Osborne was also a little surprised to hear Mpeba's account, but he believed that what Mpemba said must be the truth.

Respect for science, Osborne conducted another experiment, and the results were exactly in line with Mpemba's account. This confirms that hot water freezes faster than cold water at low temperatures. Since then, many scientific journals around the world have published articles about this natural phenomenon and named it"The Mpemba effect. "（

Put hot and cold water in the refrigerator at the same time, and the hot water freezes first. Ice is a crystallization formed by the orderly arrangement of liquid water molecules, which is a low-density rigid structure that is connected together by hydrogen bonds, while the molecular movement of hot water is more active than that of cold water, and a stable structure can be formed faster when the temperature decreases, so it will form ice faster than cold water.

Ice is a colorless and transparent solid, which is formed by the solidification of liquid, condensed in a frozen environment, and liquefied and dissolved when exposed to high temperatures.

In the atmospheric environment, the melting point of ice is 0, and when the temperature is higher than 0, the ice will begin to melt, and the filial piety substrate will become liquid front water.

The melting point of ice decreases by 1 for every 130 atmospheres of pressure, and above 2200 atmospheres, the melting point of ice increases as the pressure increases.

Brand model: Haier refrigerator.

System version: General

Put hot and cold water in the refrigerator at the same time, and the hot water freezes first. Ice is a crystallization formed by the orderly arrangement of water molecules, which is a low-density rigid structure that is connected by hydrogen bonds between water molecules, while the molecular movement of hot water is more active than that of cold water, and it can form a stable structure faster when the temperature decreases, so it will form ice faster than cold water.

Hot and cold water are put in the refrigerator at the same time, which freezes first

nbsp;Ice is a colorless and transparent solid, which is formed by the solidification of liquid, condensed in a frozen environment, and liquefied and dissolved when exposed to high temperatures.

nbsp;At atmospheric pressure, the melting point of ice is 0°C, and when the temperature is higher than 0°C, the ice will begin to melt and become liquid water.

For every 130 atmospheres of pressure, the melting point of ice decreases by 1°C, and above 2200 atmospheres, the melting point of ice increases as the pressure increases.

Brand model: Haier refrigerator.

System version: General