Snowflakes are lovely, they have fascinating shapes that are a delight to the eyes. But when the brain behind those eyes wonder how could something like that have such intricate, symmetrical structures, thoughts go puzzling. And they should’ve been more puzzling for people who were born before atoms were discovered, why? We’ll get to that in a minute.
The earliest known account in history about the hexagonal shape of a snowflake was in 135 B.C., by a Chinese scholar Han Yin. He wrote: “Flowers of plants and trees are generally five-pointed, but those of snow, which are called ying, are always six-pointed.”
But the first scientist to question “why?” was Johannes Kepler. In early 1600's he observed many similarities between a flower and a snowflake but rejected the idea that they might be connected in some way, as flowers are alive and “snow-flowers” are dead.
He tried to use a cannonball analogy to explain this hexagonal shape of snowflakes, as cannonballs tend to show a hexagonal pattern when stacked in a pile, but things didn’t work out.
Snowflake vs Snow crystal
Snowflake is a very broad term, what we mostly mean to say when we think of a snowflake is a snow crystal. A snow crystal is a single crystal of ice, the ones you see in pictures, while a snowflake can be a 100 snow crystals stuck together or a single snow crystal.
Snow crystals appear when water vapours in air convert directly into solid state – ice.
A snow crystal begins its journey as a small hexagonal plate (we’ll get to why it’s hexagonal later) Now branches start forming on its six corners as the crystal grows. It is exposed to ever changing temperatures and humidities, and each change makes the arm grow independently from the other arms.
The shape is mainly affected by two factors: temperature and humidity. i.e. Lower temperatures (less than -22 Celsius) form simple crystal shapes while warmer than that forms crystals with more branches and complex shapes.
Snow crystals. have hexagonal shapes because they reflect the internal order of the water molecules as they arrange themselves in the solid state. Water molecules in the solid state, such as in ice and snow, form hydrogen bonds with one another. These ordered arrangements result in the hexagonal shape of the snow crystal.
Are all snow crystals different? Well, the probability of there being two absolutely identical snow crystals is very low. Even though two snowflakes may form in the same cloud, their different journeys to the ground will affect their shape and size, giving each. snowflake its own unique identity.