The Physics of Snowflakes: Why Is Every Snowflake Unique?

Author
researchLatvia

January 3, 2025

natural sciences research

Snowflakes are among nature's most exquisite works of art - each is unique, shaped under complex and ever-changing conditions. Why do snowflakes always have six arms? How do they develop such intricate yet symmetrical forms? From a scientific perspective, snowflake formation reveals how ice crystals emerge, develop patterns, and achieve their unparalleled uniqueness.

The essence of science is understanding what things are made of and how they work.

A snowflake is a single ice crystal in which water molecules are arranged in a precise hexagonal lattice.

Snow crystals form when water vapor in the air turns directly into ice, bypassing the liquid state. As more water vapor condenses onto the forming snow crystal, it grows larger and more elaborate, with intricate patterns emerging in the process. It is essential to note that snow crystals are not frozen raindrops; those are referred to as sleet.

Why such complex, symmetrical shapes?

The formation of a star-shaped snow crystal begins with a tiny hexagonal plate. As the crystal grows, arms extend outward. Falling through clouds, it encounters constantly changing temperatures and humidity levels, shaping each arm slightly differently at each stage.

Sniegpārslas veidošanās process. Avots: snowcrystals.com
The process of a snowflake formation. Source: snowcrystals.com

The exact shape of the crystal depends on its specific journey through the clouds. All six arms undergo identical changes simultaneously, leading to complex yet symmetrical patterns. Since no snow crystal follows the exact same path, no two snowflakes are completely identical. The six arms grow independently, yet under similar random conditions, they develop a comparable form, resulting in mostly symmetrical crystals.

Why six arms?

The six-arm symmetry of a snow crystal arises from the arrangement of water molecules in its hexagonal lattice. As this ice crystal model rotates, the hexagonal structure becomes apparent. The crystal has a three-dimensional form, and snowflakes are similarly three-dimensional. Star-shaped plates are thin and flat, while other shapes may vary. Snow crystals begin as hexagonal prisms, each with two bases and six prism faces.

There are also irregular snowflakes, as many snow crystals are not perfectly symmetrical. They grow rapidly, sometimes leading to random side branches. These combined processes occasionally result in both complex and symmetrical or asymmetrical crystals. Snowflake formation is intricate, and much remains unexplored.

Simetrisks ledus kristāls. Avots: snowcrystals.com
Symmetrical ice crystal. Source: snowcrystals.com

The symmetrical shapes and endless variety of snowflakes are closely tied to the microscopic processes within water molecules and their paths through clouds.

Each snowflake's formation is a unique result of the interplay of temperature, humidity, and atmospheric movements.

While science has explained many aspects of these processes, much about these crystalline works of art remains mysterious.

Recommended articles

research medicine

Transforming Eggshell Waste into Next-Generation Biomaterials for Bone Regeneration

Every year, tens of millions of tons of eggs are produced, of which several million tons consist of eggshells. Although eggshells are considered valueless and are mostly discarded as waste, they can serve as raw material for producing high-value-added products. As part of the European Econom…

Latvijas Zinātnes padome

April 17, 2025

natural sciences

April Research Spotlight Artūrs Škute: Caring for Latvia’s Biological Resources

The protection of water resources and the preservation of biodiversity are becoming increasingly important for both scientists and society. A significant contribution in this field is made by Professor Dr. biol. Artūrs Škute from Daugavpils University (DU), who has dedicated more than thirty years …

research Latvia

April 14, 2025

financing research

BioPhoT Launches First Innovation Project Call for Scientists

The BioPhoT project envisions the establishment of a long-term interdisciplinary research and innovation platform, which will implement research and innovation projects through the year 2032: The BioPhoT project envisions the establishment of a long-term interdisciplinary research and innovation…

Latvian Institute of Organic Synthesis

April 11, 2025

research technologies

Wooden Bone Implants: Latvian Researchers Seek Alternative to Titanium

Latvian researchers plan to develop bone implants made from wood. So far, titanium has been unrivaled in this field. However, metal implants have drawbacks – they can promote repeated fractures and cause discomfort for patients. Riga Stradiņš University (RSU) is collaborating with the Latvian State…

Viktors Demidovs | Latvian Radio

April 9, 2025