Why dirty snow melts before clean snow?
We know that snow melts quickly or slowly due to the amount of heat it absorbs. Dirty snow can absorb more of the heat from sunlight than clean snow, so dirty snow usually melts earlier than clean snow.
Why can dirty snow absorb so much heat? It turns out that any object exposed to the Sun can only absorb part of the light and part of the heat; light and the remaining heat are reflected by the object. The more the object absorbs light and heat, the darker we look at it, the darker the black; on the contrary, the more light and heat the object reflects, the more white our face looks.
In the winter, people often use the words “a vast white area” and “clear white” to describe the field’s snow scene. Clean snow is pure white and bright, medium or clearly shows that it has a very strong reflective ability, so under the sunlight, the light and heat are relatively reflective, not easy to melt. In contrast, dirty snow looks “black,” not as pure as clean snow. Therefore, its ability to absorb light and heat is far greater than clean snow. When exposed to the Sun, dirty snow is relatively easy to melt.
In the summer, we wear white or light-colored clothes, which allow the Sun to reflect as much as possible, avoiding the body’s burning. In the winter, to get more light and heat from the Sun, people wear dark, even black clothes, keeping their bodies warm.