How Do Snow Crystals Get Formed?
Some general info about how snow forms here. Water molecules join together in a six cornered (hexagonal shaped) lattice. As the bits of the crystal gets added to (new frozen water molecules get added onto the edges) they also form 6-cornered shapes. So snowflakes are arranged in shapes of 6 basic corners/directions. These build on top of each other, making 6-cornered prisms. You might also want to ask why snow crystals are so symetrical. And the answer is… that they aren’t so perfectly symetrical (look closely next time you see a picture). As water molecules glom onto the existing snow crystal, they join on in particular patterns depending on the conditions (which are constantly, if usually slowly, changing). Joining on tends to happen at the same rate all around the snow crystal, and thus the symetrical (or near-symetrical) 6-sided look of the snow crystal. As conditions change, so do the new ways that the next molecules join on.
