Snowflakes are pretty

By Emily Jane Dennis @emilyjanedennis

It’s been cold here in NYC. After lots of mild weather, the last few cold days have been tough. Personally, I’ve found solace in three things: hockey, puppy sweaters, and snow.


 These pictures, from William Bentley’s collection are simultaneously extremely familiar and eerily otherworldly… Whenever I look at phenomenal photographs I always want to know the story behind these pictures. Really, who gets paid to document and investigate snowflakes?

The basics:
Snowflakes/crystals are made of water molecules. They begin forming when water vapor gets cooled down quickly, forming droplets with dust. As these droplets freeze, they bump into other water molecules and droplets, and grows and grows (or doesn’t). Each snowflake is made of roughly 1,020,000,000,000 water molecules! (check  my math here– assumes a 3mg flake ) Lots of snowflakes are identical, but the more complex ones are very unlikely to have a twin.

How do we know this stuff? Some really famous thinkers, Johannes Kepler**, René Descartes, & Robert Hooke (Mr. Microscope) described snowflakes as early as the 1600s, but true scientific investigation really started in the 1950s with Ukichiro Nakaya. Nakaya was a physicist and took pictures of ALL snow crystals (not just the super pretty ones) and he made the first artificial snow crystals, work that eventually led to this cool field guide:

Today, scientists like Kenneth Libbrecht, Johannes Verlinde, and John Nelson are still asking questions about snow, using more advanced versions of the same methods that Nakaya started with: observation and experiment. On the observation side, these men take helicopters into snow clouds to collect samples; they use millimeter wave cloud radar to provide data on cloud size, location, and composition; and they take detailed images of natural snowflakes that result from these conditions. Then they take this information back to the lab and use computers and fancy equipment to try and replicate what they see in nature. Then they can adjust a variable (like temperature, pressure, time, or the other particles floating around in the air) and see how that changes the resulting snowflake.

Why study this problem? Snowflakes are (mostly) made of just one molecule : H2O. This makes it an “easier” way to study crystals, which can be made up of lots of different molecules/building blocks. By studying simple examples, we can learn a lot about things that seem more complex to us (like how studying yeast can help us understand cancer, human development, genetics, and disease) Here’s a list of a few questions that can be tackled by studying snowflakes:

  • How do ice particles hold electrical charge?
  • How do crystals grow?
  • what are the environments in which crystals grow best/fastest/most regular?
  • How are different patterns formed?
  • How long does it take?
  • How does the surface of an ice crystal influence how it grows?
  • How many shapes can a crystal made up of lots of one thing (like water) make?
  • If the water joins up with other molecules, how that influence the final crystal?
  • Why are artificial snowflakes less complicated than natural ones — what have we missed?

Why should we care?
Okay so not all of us are purely driven by curiosity. History tells us that basic science is necessary, and that curiosity-driven research has yielded some of the coolest and most important advances in science (Penicillin, GFP, and radioactivity to name a few) Here are a few ways that knowing more about snow might help advance technology and may impact future day-to-day life.

  • Understanding lightning: thunderstorms are made of “charged” clouds. We don’t really understand lightning yet, but we do know the conditions required for it and, you guessed it, all of the current hypotheses require ice crystals. But how do ice crystals collide and become a charged cloud? No one knows… yet.
  • Weather forecasts: The more we learn about ice, the more we’ll know about clouds. This gives us better information for the computers that predict the weather… No more surprise showers!
  • Nano-tech: Nanobots, nanosurgery, nanoparticles… the applications of future nano-technologies are everywhere, but how do we make these tiny, tiny things? If we first learn about how Nature has solved the problem, we might not have to solve it ourselves!
  • Computers: Silicon crystals are necessary for computers: learning more about water crystal formation helps us find, make, design, and improve silicon products—eventually leading to faster, cheaper, better computers. Awesome.

Also check out:
A kid-friendly primer on snowflakes
A simple but thorough review (warning: includes some math!)
And for a more hands-on experience, make your own snowflakes!
Or go outside! Bring something dark (coat, paper) and a magnifying glass

For information about how pretty/cool came to be, check out this story.

These views are the work of individual authors, do not necessarily represent the views and opinions The Rockefeller University, and are not approved or endorsed by The Rockefeller University.

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