Most people know what a snowflake looks like, but how many people have actually looked at a snowflake up close? These tiny crystals of water are extremely delicate and fleeting. They melt within seconds on a human hand. How do we know exactly what snowflakes look like? How do we know that “no two snowflakes are alike”?
We have Wilson Bentley to thank for publishing the very first photographs of snowflakes (or snow crystals, a more accurate term). Wilson Bentley is affectionately known as “Snowflake Bentley” today, because of his incredible success with photographing these delicate wonders of nature.
Wilson Bentley was born in 1865, and grew up in a rural town in Vermont. He had a keen interested in photography, as well as snow crystals. He began attempting to photograph them underneath a microscope.
The process was challenging, because a microscope requires light, which generates heat. He had to work very quickly in order to capture images before his snowflakes melted. He went on to capture thousands of images, and his results are captivating.
Not only are these photographs beautiful to look at, but Bentley made countless observations about the weather conditions that cause the different kinds of shapes to form. He divided snow crystals into several different categories, and discovered that different crystal shapes will grow at different temperatures.
(This is a collage of Bentley’s images compiled by Dorothy Wallace-Senft)
Using these observations, Bentley was able to estimate the temperature outside based on the type of snowflakes that were falling. Pretty cool, right?
Today, we understand that air temperature as well as humidity control how snow crystals grow.
Many of the shapes in this diagram are not what we would consider to be “typical” snowflake shapes. However, you can see in this diagram that the classic “dendrite” form only grows in very moist and relatively cold conditions.
We also now have identified many, many more categories of snow crystal shapes.
Want to learn more about snow crystals? Check out this cool website by Dr. Kenneth Libbrecht. There is lots of great information about snow crystal forms, and he grows some pretty cool “designer snowflakes.” This is an art in itself, and Dr. Libbrecht can claim the impressive title of “snow crystal artist.”
So, no two snowflakes are alike, correct? Not so! Check out these identical-twin snowflakes.
These snowflakes are grown in the lab under identical temperature and humidity conditions, resulting in an identical crystal shape. Is this possible in nature? Maybe we’ll never know…
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