A snowflake of another shape
With the mountains of snow piled up around here after our record-breaking blizzard, it’s hard to imagine that each little flake is so tiny and so intricate. Snowflake shapes and myths have captured the imagination of children, grown up children and even scientists.
Scientists have always known that snowflakes are hexagonal (six-sided) but for hundreds of years, snowflake watchers have been seeing three-sided snowflakes as well. Until recently, it has been a mystery how these snowflakes formed. In the quest for knowledge, scientist Kenneth Libbrecht created a proverbial snow globe in his lab in sunny southern California.
He created an artificial snowfall and then collected samples to study their shapes. Of course there were quite a lot of hexagonal snowflakes with sides of basically equal length. Surprisingly they found substantially more triangular snowflakes than expected. Maybe they aren’t so rare after all!
So, why does this happen? Libbrecht reasoned that as a snowflake falls, it may come across a tiny dust particle in the air. This dust particle causes one edge of the snowflake to point up. Because of this, the two sides still pointing down might tend to grow faster as the wind blows and adds more fluff to the growing snowflake.
Libbrecht, a physicist, uses his snowflake research in the study of aerodynamics as well. Understanding aerodynamics is critical to understanding snowflake movement and growth, just like it’s critical to building airplanes and launching rockets. Who would’ve thought that something so small and something so big have the very same principles in common?
sciencenewsforkids.org
photo: Kenneth Libbrecht
