So why does evaporation absorb heat?

This is because in the process of evaporation, liquid molecules are separated from the liquid surface, and it is necessary to overcome the attraction of the liquid surface. This attraction comes from the attraction between liquid molecules. It takes a certain amount of energy to separate molecules from liquids. This energy comes from the thermal motion of molecules, that is, the thermal energy of liquids. Therefore, in the evaporation process, the liquid will absorb heat, which will lead to the cooling of the surrounding environment.

The principle of heat absorption by evaporation can be verified by experiments.

We can take two identical hygrometers. The mercury column of one hygrometer was washed with alcohol, and the mercury column of the other hygrometer was washed with alcohol and then washed with alcohol. Then, immerse the mercury columns of the two hygrometers in a drop of water. Under the blowing of the fan, we will find that the mercury column on the hygrometer evaporates faster and the temperature drops faster. This shows that heat is absorbed during evaporation.

Besides absorbing heat during evaporation, evaporation has other characteristics. First, the evaporation rate is related to temperature. The higher the temperature, the more intense the thermal movement of molecules in the liquid and the faster the evaporation rate.

Secondly, the evaporation rate is related to the liquid surface area. The larger the surface area of the liquid, the faster the evaporation rate. So when hanging clothes, we will spread them out to increase the surface area and accelerate evaporation. In addition, the wind will also increase the evaporation speed, because the wind can take away water molecules and reduce the attraction of the liquid surface.

Evaporation endothermic is a common physical phenomenon. Evaporation is the process of changing liquid into gas, and the heat absorbed during evaporation leads to the cooling of the surrounding environment. The evaporation rate is related to temperature, liquid surface area and wind force. Evaporation endothermic phenomenon also has some practical applications in our daily life. By understanding the principle and application of evaporation heat absorption, we can better understand this phenomenon in the physical world.