The mystifying qualites of water never cease. From its unique polar molecular structure to its ability to occupy all three states of matter on the same planet, which most compounds only comprise one or two naturally, this element is responsible for all life on earth and yet could easily kill it with the same qualities that make it so useful.
So let’s look at a basic property of water, its color, particularly in its frozen state. Water is one of the few materials that will harden the colder it gets and not get brittle. In its frozen state pure water can be perfectly clear depending on the circumstances when it is frozen. As it freezes water forms crystalline structures that when lined up right will let light pass through easily. Sometimes impurities will discolor it, but for the most part it’s nearly clear when formed.
So why snow is white can be somewhat confusing. The best analogy to water in its frozen state, which snow is, is to relate it to diamonds. They are both similar in crystalline structure and both have similar properties regarding light. When a diamond is polished perfectly, was formed in the right conditions and free of impurities it is like glass; start grinding corners and edges into the diamond and it begins to bounce light around inside its crystalline structure creating the deflecting light patterns that seem to make them shine. What diamond cutters are basically doing is taking a clear crystal and making it appear to shine by giving it many more sides to reflect light from. This is exactly what happens to snow. It’s interesting to also note that diamonds are the only known substance besides extreme gravity that can actually slow the speed of light inside its crystalline structure.
What happens when snow is laid, is that small particles of crystalline ice structures, similar to the diamonds, are blown around in the upper atmosphere and bouncing into each other and breaking themselves into smaller crystals before finally reaching the ground. By that point, they are so small and multi-faceted, that instead of letting light pass through almost unscathed like ice, it’s refracting around all the tiny crystals and reflecting back all visible colors of the electromagnetic spectrum, also know as the color white. Snow can basically be thought of as diamond dust, and pure ice as a polished diamond.
Another interesting thing to note about snow, and water in particular, is that as it occupies the three states of matter, in two of these states it reflects light and as a liquid it absorbs light?! This makes an interesting case for water as a cooling mechanism for the earth by helping the ozone reflect light before reaching the earth and increasing its overall energy/mass value, ie. making it hotter over time. It’s also interesting that the two states of water that reflect light, gas and solid, exist in the upper atmosphere also, as steam and snow!
