Most people have heard the saying that no two snowflakes are identical. But with countless snowflakes produced in every winter flurry, could such a thing be true?
Well, according to Jason Benedict, a chemist and crystal expert at the University at Buffalo in New York, the answer is yes!
This is because snowflakes are made of tons of water molecules that have become linked to one another, usually forming around a central point of dust or dirt. Scientists call this nucleation (pronounced noo-klee-ay-shun).
“So there’s this teeny, tiny microscopic foreign object,” said Benedict, “and that gives the water molecules something to hold onto.”
The shape these ice crystals take as they form is the result of many factors, including temperature, humidity and air pressure — all of which are constantly shifting and changing as the winds blow. This makes the likelihood that each water molecule in that snowflake would sit in exactly the same place as each water molecule in another snowflake extremely unlikely.
“It just won’t happen,” Benedict said.
So does a snowflake’s structure have anything to do with whether it will be good for making snowballs, as opposed to sled-riding? Well, sort of. In fact, temperature is the main decider of what kind of outdoor fun you’ll be having on a snow day.
Benedict said light and fluffy snow, which is great for skiing, snowboarding and sled-riding, is usually the product of very cold temperatures, because all the water molecules have frozen solid. Warmer temperatures produce snow that still has plenty of liquid water molecules, creating a sticky and wet winter wonderland for building snowballs, snowmen and snow forts.
You can do an experiment with another common crystal to see how this works.
With your parents’ permission, stand over a sink and see if you can pack a handful of sugar into a solid “snowball.” Doesn’t work, right? Now add just a few drops of water and knead it together.
“What you see is the sugar starts to stick together,” Benedict said. “The liquid water is acting almost like a glue.”
If you think that’s fun, you should consider entering Benedict’s annual U.S. Crystal Growing Competition, where thousands of students from across the country compete to see who can grow the largest and highest-quality crystals. (Entries are typically accepted beginning in late summer.)
Crystals are a huge part of our daily lives. Not only are they the basis for things such as snow, sugar and salt, but Benedict says crystals are important components of computers, solar panels and medicine. So the next time tiny crystals start falling from the sky, take a moment to appreciate where they came from. Perhaps you’ll be inspired to create crystals of your own.
Correction: An earlier version of this story incorrectly named Jason Benedict’s employer the University of Buffalo. It is the University at Buffalo. The story has been updated.