In 1611, German astronomer Johannes Kepler published a short essay in “Six-Cornered Snowflake,” the first scientific book on snowflakes. Kepler questioned why snowflakes always showed hexagonal symmetry. However, he also realized that the technology of his time was not sufficiently advanced to help answer the question. It turned out that it took approximately 300 years before Kepler’s question could finally be answered. It required the development of X-ray crystallography.
In 1637, French philosopher and mathematician René Descartes first published sketches of his snowflake observations in a meteorology journal. After that, many scientists showed interest in snowflake research. Rapid progress was made in the study of snowflakes in the late 17th century when the microscope was invented. In particular, English physicist Robert Hooke published pictures of snowflakes observed under a microscope in his book “Micrographia.” Through those pictures, many people learned how complex and symmetrical snowflakes are.
Descartes’ Snowflake Sketch
The first person to photograph snowflakes was e and snowflake photographer Wilson Bentley (1865-1931), who took over 5,000 photographs of snowflakes over his lifetime. Bentley published his famous book “Snow Crystals,” which contains more than 2,000 photographs of snowflakes, in 1931. The book is still being published to this day. Bentley wrote in his essay that the detailed shapes of snowflakes explain the process of their formation and the many changes they have gone through while drifting through the clouds. By analyzing weather maps over a long period, he found that the shapes of snowflakes reflect the weather conditions (temperature/humidity in the sky) at the time they fell.
Bentley’s Snowflake Photographs
What are the hexagonal symmetrical structures that can be seen in snowflakes? Ice crystals!
They’re created by the arrangement of water molecules in the lattice. Snowflakes develop a hexagonal structure as they drift through the clouds and grow.
The Structure of Hexagonal Snowflakes
Snowflakes have three-dimensional structures. The star-shaped snow crystals begin by forming small hexagonal plates, and, as the crystals grow larger, twig-like shapes emerge from the six corners. As they fall from the clouds, the crystals go through changes in temperature and humidity, and these changes alter the shape of the twig-like structures. The exact shape of a snowflake is determined by its path through the clouds. As a snowflake falls, the surrounding water molecules stick to its crystals, reducing the humidity around it. This difference in humidity causes the outer water molecules to spread rapidly. In particular, the hexagonal corners grow faster and branch out like twigs. Within a single crystal, the humidity varies according to the distance from the center of the crystal. Therefore, the environment is almost the same when it is at the same distance from the center. So, the six arms at each corner grow at the same time to create a complex yet symmetrical shape.
The Growth Process in Snowflake
The Shape of Snowflakes
The first person to conduct a truly systematic study of snowflakes was Japanese physicist Nakaya Ukichiro, who made great progress in our understanding of how snowflakes are formed. While working as a professor at a university in Hokkaido that didn’t have nuclear facilities, Nakaya, a nuclear physicist, decided to focus on studying snowflakes, since they were abundant in the area. He observed all types of snowfall and through those observations identified and made lists of the major snowflakes. Unlike Bentley, Nakaya photographed not only the beautiful and symmetrical snowflakes but also many other kinds.
However, Nakaya’s true achievement lies elsewhere. His true achievement, in fact, was growing artificial snowflakes under controlled conditions in a laboratory. In his study of these artificial snowflakes, Nakaya was able to explain the shape of the crystals under various environmental conditions, providing a very important clue to understanding the physics of snowflake formation. His studies showed that how snowflakes grow is highly dependent on the temperature and humidity of the clouds they’re in. A closer look at “The Snow Crystal Morphology Diagram” that Nakaya created reveals that hexagonal stellar snow crystals, which are what we think of when we think of a typical snowflake, grow in a narrow temperature range of around -15°C, coupled with high humidity.
Even under the same temperature conditions, if the humidity decreases, the hexagonal branches become simpler and eventually form into thin hexagonal plates. In other words, more detailed, branched crystals grow in high humidity. Needle-like and columnar crystals are usually observed in the -6°C range, and simple prism-shaped crystals grow in low humidity. However, the reason why snowflakes grow in this way is still not fully understood. Science may have made great progress in understanding the secrets of the universe, yet the structure of snowflakes remains shrouded in mystery.
The Shape of Snowflakes
Reference Provided by Edunet T-Clear
※ Picks respects the rights of all copyright holders. If you do wish to make material edits, you will need to run them by the copyright holder for approval.
more from
Edunet·T-Clear
BEST STORIES
ETX
'Why do some people tolerate heat better than others?'
2024-07-17 00:00:00
Mindswitch
Music that lulls you into a sweet nap
2024-08-10 00:00:00
AFP
'Life goes on' - Panama islanders relocated as sea level rises
2024-06-07 00:00:00
Inven Global
LCK Summer Split 2024 Cheat Sheet: Teams, Schedule, and Where to Watch
Descartes’ Snowflake Sketch
