snowflakes, winter's secret beauty
SNOWFLAKESWinter’s secret beauty
Snowflakes are conglomerations of frozen ice crystals, which fall through the Earth's atmosphere. They begin as two snow crystals that develop when microscopic supercooled cloud droplets freeze. Snowflakes come in a variety of sizes and shapes. Complex shapes emerge as the flake moves through differing temperature and humidity regimes.
Every snowflake has infinite beauty and it is said that no two snowflakes are exactly alike; however, many crystalline structures are often related to another mathematical concept: Polyhedra. Many of the crystal-structures found in nature, including snowflakes,
come in the shapes of different kinds of polyhedra such as octahedrons and tetrahedrons.
What are snowflakes?
FormationSnow crystals form when tiny supercooled cloud droplets freeze. These droplets are able to remain liquid at temperatures lower than −18°C (0 °F), because to freeze, a few molecules in the droplet need to get together to form an arrangement similar to that in an ice lattice; then the droplet freezes around this "nucleus." The water molecules in an ice crystal form a hexagonal lattice, as shown to the right (structures show different views of same crystal). Each red ball represents an oxygen atom, while the grey sticks represent hydrogen atoms. There are two hydrogens for each oxygen, so the chemical formula is H2O. The six-fold symmetry of snow crystals ultimately derives from the six-fold symmetry of the ice crystal lattice.
No two snowflakes are truly alike, but they can be very similar to each other, said Janko Gravner, a mathematics professor at UC Davis. Intricate, incredibly variable and beautiful, snowflakes have been puzzling mathematicians since at least 1611, when Johannes Kepler predicted that the six-pointed structure would reflect an underlying crystal structure. Snowflakes grow from water vapor around some kind of nucleus, such as a bit of dust. The surface of the growing crystal is a complex, semi-liquid layer where water molecules from the surrounding vapor can attach or detach. Water molecules are more likely to attach at concavities in the crystal shape.