The formation of a snowflake begins when a microscopic cloud droplet freezes as a tiny ice particle. Water vapour that condenses on its surface causes the ice to develop flat, polished surfaces, known as facets, which continue to grow into a hexagonal prism shape. At each corner of the hexagon shape, new branches extend outwards each at the same rate. All snowflakes have six sides and can be either prism-shaped, plate-shaped or star-shaped.
As the snowflake moves around within the cloud, it encounters a variety of temperatures that change the growth behaviour of each flake, causing the six branches of the crystal to grow in exactly the same way, creating six-way symmetry and a unique flake every time.
The first person to photograph a snowflake was American Wilson Bentley. Bentley took his first snowflake snap in 1885, using a bellows camera and a compound microscope, and went on to assemble a large collection of beautiful snow crystal images.
Discover more amazing science in the latest issue of How It Works magazine. It’s available from all good retailers, or you can order it online from the ImagineShop. If you have a tablet or smartphone, you can also download the digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, make sure you subscribe today!
Plus, take a look at: