Now, what if you aren’t looking through an inch of solid, smooth ice but a multitude of dainty snowflakes? Snowflakes form directly from the vapor phase of water into the lovely crystals snowflakes are so famous for. These ice crystals form with hexagonal (six-sided) symmetry, so each crystal has many sides or crystal faces. When incident light hits a snowflake, some of the light is reflected off the crystal back towards the observer. However, most of the light penetrates the crystal and is bent, or refracted. Now, a snowflake has such a complex, intricate structure that this light hits internal crystal faces and bounces around inside the crystal. The combination of reflection and refraction is so efficient for an ice crystal that, ultimately, most of the light actually bounces back towards the light source and the observer. Since all the colors in sunlight add to give white, what we see when we look at snow is white: the sunlight that has reflected off and refracted through the water (ice) crystals to come back at us.
- Department of Physics | Union University
