Is every snowflake unique?

This week, Charlotte Birkmanis has been looking into Alan’s cool question...

Charlotte - As snowflakes aren't something we see here all that often, I couldn't tell you if they're ever the same, but imagine if, in the entire history of the world there have never been two identical snowflakes – or ... maybe there have been and we’ve just never noticed. To explain if this is possible, we have Jason Benedict from the University of Buffalo … who had s'no problem answering this for us .

Jason - What a wonderful question! It is certainly true that no researcher has ever found two snowflakes that are ‘the same’. But this centers around what is meant by ‘the same’. Because of its importance to the world in which we live, water and its solid form ice have been studied very extensively. Through experiments in which the conditions were very carefully controlled, researchers have attempted to grow identical snowflakes, however, even under nearly perfectly controlled conditions the snowflakes were still different. Depending on the temperature, water molecules are actually moving around on the surface of ice! So one could even argue that a single snowflake is not even the same snowflake after you’ve looked at it! How cool is that!

Charlotte - I have to admit, that IS very cool!

Jason - So could there ever be two identical snowflakes? Possibly. If the crystals were super small (nanosized with a very small number of water molecules) and super cold (stop water on the surface from moving), it seems possible that one could create two identical ice crystals. How’s that for a challenge to the ice scientists of the world!

Charlotte - AlanCalverd points out on the forum “Even if you found two structures with the same underlying fractal symmetry, they would almost certainly not have the same number of molecules”. Thanks to Alan for his frosty question, and for Jason’s n-ice answer. Join us next week when we might be out of our depth, as we consider Richard's question/

Richard - Will a can of soda dropped in the ocean sink until it implodes, or will it float once the density reaches equilibrium?