The Science of Snow!

The Science of Snow!

Stellar dendrites are falling. Rimed crystals are piling on so heavily, they you may see graupel. If you’re lucky you may spot a split star or a rare capped column. No, I’m not talking gibberish! You can check the “Meteorological Classification of Natural Snow Crystals,” (1966) by Magano and Lee.  Did you know that there are 80 official patterns of snowflakes? Their characteristic 6-sided shape comes from the hexagonal lattice of water molecules: each vertex has an oxygen atom with the edges formed by hydrogen bonds on either side (see http://goo.gl/8ZUI0G). 

Is it true that no two snowflakes are alike? The short answer is yes! At the atomic level, suppose one snow crystal has 10^18 water molecules, of which 10^15 will contain deuterium isotope (hydrogen with mass of 2 instead of 1) or an isotope of oxygen (mass of 18 instead of the more common 16). Imagine the different ways these could be arrange in the crystal. Then consider the hundreds of different morphological features of snowflakes and the ways they may be arranged. If 100 books could be arranged on a shelf in 10^158 ways (1 followed by 158 zeroes, which is more than all the estimated atoms in the universe), the probability that two identical snowflakes exist is infinitesimally small.  

How to view a snowflake at >1,000 times magnification? What you see will surprise you. They don’t look quite that regular or perfect. Their art form is more steam punk than a Hallmark holiday card. You may even see the face of Optimus Prime or an alien starship.  

1) Capture freshly fallen snow from around the country. It’s more naturally diverse than the man-made stuff that is smooth and gob-like.

2) Brush the flakes on to a pre-chilled copper plate coated with a gel of methyl cellulose.

3) Chill right away in liquid nitrogen, down to -196 C.

4) Mount on a scanning electron microscope with a viewing stage chilled to -176 C.

5) Justify your work: “‘Information gained from studying the structure of snow is vital to several areas of science as well as to activities that affect our daily lives…”  from USDA.gov 🙂

Happy Holidays! 

REF: For all you wanted to know about snow and more http://goo.gl/nDnTM

Cover Photograph by Ph.D. candidate Si Chen. Dartmouth Engineer Magazine http://goo.gl/FsqqR1

Others: The Electron Microscopy Unit of the Beltsville Agricultural Research Center in Beltsville http://goo.gl/xteHY

#ScienceEveryday   #HolidayScience  

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59 Responses to The Science of Snow!


  1. You’re so amazing.  Thanks for sharing.

  2. Rajini Rao says:


    You mean auto-awesome, Panah Rad 🙂


    I was pleasantly surprised at Google’s holiday enhancement of the microscopic snowflake. 

  3. Jim Carver says:


    Gettin’ a little out of your leauge there aren’t you Rajini? That’s getting dangerously close to Earth science and you could get ignored.

  4. Rajini Rao says:


    Have a good holiday ahead, Jim Carver  and Thex Dar ! 


  5. That’s awesome Rajini Raolove the auto awesome effect! Happy holidays to you guys 🙂


  6. Anyone interested in this subject needs to get over to fellow Google Plusser Don Komarechka right away, where he posts daily macro photos of snowflakes.  I just got his magnificent book, self-published through an indiegogo funding campaign and it is astonishing! Incredible beauty, the science of the varieties of pattern and formation and the technical details too for a photographer.  He shoots macro with a ring light, handheld and maybe scores of photos of each single flake.  Focus-stacking and about 4 hours of work for each image.  You can also watch a recorded interview with a photography show this week with Jan Kabili and Ron Clifford .  If you have a chance to get Sky Crystals, Unraveling the Mysteries of Snowflakes, you are very fortunate for making Don’s acquaintance!


  7. Rajini Rao you have the best science posts! The autoAwesome Snow is a nice touch 🙂

  8. Rajini Rao says:


    Thanks, Buddhini Samarasinghe , and holiday cheer to you too!


    Hudson Ansley , thank you..this is fun for me too 🙂


    BJ Bolender , thanks for tagging Don (and others). I recall sharing his stunning images through ScienceSunday .

  9. Rama Drama says:


    The mystery inside snowflake maybe broken, magnified and revealed but the allure and magic they create in their whispers when one sees them goes beyond the molecules 🙂 Thanks for the science part Rajini Rao! Now I will go about my dreaming about them 🙂

  10. Rajini Rao says:


    Rama Drama my dreams are molecular 😀

  11. Chad Haney says:


    Great post Rajini Rao. Two core facilities will be added to the one that I manage, under the umbrella of a new center. One of those cores has a TEM. I might have to try your suggestion under the guise of learning how to use TEM. I need to know if I’m  going to manage that facility, right?

  12. Rajini Rao says:


    Happy Holidays, Chad Haney ! (My lab is already pretty empty hence my holiday spirit 🙂


    Yes, good excuse teaching strategy. Congrats on the addition of new core facilities and more science in the new year! 

  13. Panah Rad says:


    Rajini Rao haha. Yes. That’s a good one 🙂

  14. Chad Haney says:


    Thanks Rajini Rao. I hope it’s more science and not more administration. I think there will be some teething pains and then I can focus on resuming my own research.

  15. Rajini Rao says:


    In these times of tough funding, the admin work brings in some much needed $$ even if it is a chore, Chad Haney . 

  16. Chad Haney says:


    True Rajini Rao. One of our users/collaborators got a JIT request this week. I hope that means she got a fundable score. Another user/collaborator is in the 7th percentile for their R21. Both are good for my facility and the tiny slice of salary support is good on paper but not really needed. It’s scary to think that someone in the 7th percentile is concerned about being on the edge of the payline. CRAZY TIMES.

  17. Rajini Rao says:


    I just heard of a grant in the top 9th percentile having to go through resubmission 😦 


    On that cheery note….!

  18. Chad Haney says:


    I hope it wasn’t your grant Rajini Rao. Cheerio!

  19. Rajini Rao says:


    I did indeed recall your ‘pet peeve’ when I wrote this, Peter Lindelauf . I’m sure Michelle Beissel does as well 🙂

  20. Rajini Rao says:


    For a frosty blast from the past, here is an older post by John Baez showing a 1954 classification of snowflake types: http://goo.gl/knH6Xa

  21. Rajini Rao says:


    Love ya right back, Peter Lindelauf . Truth be told, I was somewhat nervous about putting that section in 😛


  22. How about sand grains? Are all of them unique also? 🙂


    Happy Holidays, Rajini Rao !


  23. Thanks for bringing this post to my attention BJ Bolender, and thanks for sharing the magic of snowflakes Rajini Rao!


    It’s interesting that some very similar snowflakes have shown up in my stream over the past few weeks. White electron microscopy can be really fun to see, snowflakes are still within the limits of traditional photography with visible light. These images remind me of clay sculptures, and I remember stumbling across an archive with around a hundred such pictures in my research for my new book.


    On the point about no two snowflakes are alike, it should asked at what point does a collection of water molecules constitute a “snow flake”. They have to start somewhere, and without complete accuracy of molecular bonds one could assume that unimaginably small hexagon-shaped snowflakes may appear identical with certain equipment and basic measurements. Of course, that usually doesn’t fall under the traditional definition of a snowflake. 🙂


    Peter Lindelauf I also agree completely!


  24. stellar dendrites! Rajini Rao everything you post is fascinating.

  25. Mary T says:


    Beautiful post Rajini Rao ~ Happy Holidays!


  26. I wonder what the probability is that two snowflakes APPEAR identical to the naked eye? (or some standard naked eye, or something like that).

  27. Rajini Rao says:


    Mara Rose and JoEllen Donahue Hermes , thank you and happy holidays! Hope you have some time to relax and unwind before the new year.

  28. Rajini Rao says:


    stefan jeffers , good point..at low resolution, snowflakes belonging to the same subtype may well appear identical. I was surprised to see how imperfect many of the snowflakes are…it appears that photographers have to search around to find a symmetrical ones. 


  29. Happy Holidays, Rajini Rao 

  30. Rajini Rao says:


    Deborah L Gabriel , all the best of the season to you too! Hope you get some time to relax and recharge before the new year starts up again. 

  31. Joan Hogol says:


    This is when real things are more beautiful than fantasy things 🙂 

  32. Rajini Rao says:


    And when reality is more fantastical than fantasy 🙂


  33. Peter Lindelauf


    Guess that might be true of “identical” twins? Have some in my family, one a little thinner than the other 🙂


  34. Unity in diversity! On the macro level… some become snow angels, others snow men, snowballs, igloos, huts and more. Given a little water some become ice skating rinks while others turn to slush and with repeated pressure some become slick ski slopes or icy toboggan runs. Really enjoyed reading all about snowflakes, Rajini Rao. Love those posts I am able to see and read. Happy holidays.

  35. Rajini Rao says:


    You have a beautiful way of looking at the world, Donna Pezeshki ! Your words paint a vivid picture of wintry wonder 🙂


    Happy holidays and all the best in the upcoming new year to you and yours! 


  36. Happy holiday to all google fans ..

  37. Kawthar A says:


    Thank you for making science interesting for us ❤ Rajini Rao 


  38. Did a similar post last week, fascinating insight and an ideal post for this time of year 😀

  39. Rajini Rao says:


    David Dhannoo thanks for alerting me to your snowflake post! Here it is, everyone, a cool gif and some interesting information on how temperatures shape the morphology of the snowflake: http://goo.gl/ZqOqR3


  40. A pleasure and an honour Rajini Rao 🙂

  41. Mad B says:


    Nice Rajini Rao And appropriate Google ‘pimping’ snowflake effect. For fantastic snowflakes pictures http://bit.ly/1hw6f6k 

  42. Rajini Rao says:


    Madjid Boukri , thanks for the link to stunning images of snowflakes with colour, thanks to optical interference, again from Don Komarechka . It is interesting as he points out, that the snowflakes start off symmetrical, but growth becomes more “chaotic” towards the tips and variations appear. 

  43. Mad B says:


    Yep almost like ‘genetic’ variations. Those are ‘sick’ snowflakes :))

  44. Rajini Rao says:


    Haha, now I’m going to look at the people around me and imagine them as snowflakes 🙂


  45. Beautiful and I just love 5)!

  46. Marta Rauch says:


    Rajini Rao excellent! Thank you 🙂

  47. Bill Collins says:


    Hm. Do you know where to get inexpensive copper plates?

  48. Rajini Rao says:


    Bill Collins no, but I know where to find an expensive scanning EM 🙂

  49. Bill Collins says:


    Bugger. I’ll settle for admiring the photos. Thanks for the article!

  50. nizar M H says:


    naturel seen nice feeel

  51. Rajini Rao says:


    Pete Joyce , yes indeed! 🙂

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