Waking up last Wednesday, I took a glance outside to witness a featureless, gleaming expanse of white encasing the whole street. A minute, ashy substance was descending from the sky, and I knew immediately what this meant – the apocalypse had arrived. Yellowstone had finally erupted, and was scattering volcanic debris across the entire globe. If we didn’t die from building collapse, our lungs would surely suffer from particulates suspended in the air… Alternatively, it was snowing, but that’s such a rare event that I think I can exclude the possibility.
Thankfully, it’s not quite the end of the world yet. Well, not for us at least. I can’t say the same for you lot in America. My thoughts go out to you.
Snowfall is indeed such a rarity in the UK that I feel if I don’t talk about it now, I might never have the chance to, apart from in the past tense. Even when we do experience the occasional snow during the winter, it never lasts for long, and is just no damn good for building snowmen with.
In nature, there exists a substance we call H2O, which has many interesting properties, one of which allows you and me to keep on living. This H2O can often be found lying around in clouds in the form of tiny water droplets, stuck onto dust or pollen grains. When temperatures are lowered to the freezing point of water, the
se droplets of water freeze around the particle, forming a hexagonal crystal of ice. This particular structure is due to the specific angle of bonds in H2O molecules, and the hydrogen bonding present, which I will discuss in more depth in a later post.
This newly formed snowflake “seed” is heavier than the surrounding air, so it begins its journey down to Earth. As it falls through the humid atmosphere, more water droplets stick to the crystal and freeze, repeating the hexagonal pattern. Simply because the corners of the hexagon tend to stick out more, probability dictates that the water sticks onto these areas, which makes arm-like structures to stem from each corner. The intricate shape of each ‘arm’ is determined by the atmospheric conditions experienced by the crystal as it falls.
It is true that every snowflake is unique. No snowflake is able to be subject to the exact same conditions and cross the same path as another snowflake. On top of this, we could examine the water on a molecular level and see that they are made up of different arrangements of isotopes.
This is what makes them so special. The fact that we could spent an eternity capturing and observing snowflakes but not find any two that are the same is fascinating. Maybe we should put more effort into keeping the Earth cool. Give it some shades (literally?).