Why should salt be sprinkled on snowy days?

The principle is to use the solubility and hygroscopicity of salt and the low freezing point of brine. When salt is sprinkled on snow, due to its solubility and hygroscopicity, the salt will absorb the water on the snow surface, so that the salt will begin to melt and become a solution that erodes the snow layer. When salt and snow melt into salt water, the freezing temperature of salt water is lower than that of water, so it is difficult for salt water to freeze to form ice layer.

Chlorinated salt can melt snow because the freezing point of water is 0℃. When chlorinated salt is dissolved in water (snow), the freezing point of brine will drop below 0℃.

For example, after sodium chloride is dissolved in water, the freezing point is about-10℃; When calcium chloride is dissolved in water, its freezing point is about -20℃. When acetic acid is dissolved in water, it can be reduced to about -30℃. In this way, the original solid snow becomes liquid and becomes "salty snow water", which will flow away from the sewer.

Causes of salt sprinkling in snowy days

The road surface is slippery after snow, which is easy to cause traffic accidents. The reason why salt is sprinkled on the road surface is that salt dissolves in water and releases a lot of heat, which can make the snow melt as soon as possible and not easily freeze the ground. If salt is sprinkled on the ice, the salt will dissolve in water and release heat, which will also melt the ice, thus enhancing the friction on the ground and reducing the occurrence of traffic accidents.

After sprinkling salt, the water around the snow becomes salt water, so it can't solidify. In this way, the snow will continue to melt, but it will not solidify back, so it is less and less, and the price of salt is cheap and there is no pollution.