What is the difference between frozen snow and ice?
Frozen snow is a large number of tiny ice crystals piled up together with a lot of air spaces in between. It looks so white precisely because of this structure, in which there are an infinite number of ice-air interfaces to scatter the incident light. Indeed, there is so much entrapped air that people buried under snow can actually survive for quite a while if they use some porous covering on their faces. Ice is highly compacted frozen water from which all air pockets have been removed. This happens under pressure. For example, the thick mass of ice, some kilometres deep, on Antarctica is quite transparent. The water constituting this ice must have precipitated as snow, some of it thousands or millions of years ago. There is also, of course, the ice we make in the freezer compartment of our refrigerator. That is also transparent. Clearly, the conditions in our freezer are not designed to make snow, though you must have noticed that freezing of moisture on the walls of old freezers resu
