Snowflake symmetry in layman's terms

[XJETGIRLX]

After visiting this site (http://www.snowflakebentley.com) I got curious about why snowflakes are symmetrical.

Thus I found this site (http://www.sciam.com/askexpert_question.cfm?articleID=00025ADD-C9A7-1C71-9EB7809EC588F2D7) which explains:

Snowflakes are symmetrical because they reflect the internal order of the water molecules as they arrange themselves in the solid state (the process of crystallization).

.....

The growth of snowflakes (or of any substance changing from a liquid to a solid state) is known as crystallization. During this process, the molecules (in this case, water molecules) align themselves to maximize attractive forces and minimize repulsive ones. As a result, the water molecules arrange themselves in predetermined spaces and in a specific arrangement. This process is much like tiling a floor in accordance with a specific pattern: once the pattern is chosen and the first tiles are placed, then all the other tiles must go in predetermined spaces in order to maintain the pattern of symmetry

And all this left me going, "huh?"

Okay, I get that crystallization results in a geometric pattern, and the crystals are arranged according to their molecular structure, but the floor tiling analogy just kinda threw me for a loop.

'Predetermined pattern'? Where is this pattern determined? Are all the water molecules alike? If so, then why are there different general formations for snowflakes?

[Nametag]

Yes, all water molecules are alike. That's why it's all water.

And I can take a set of square tiles and make all kinds of designs with them, but they're all going to have bi-fold or four-fold symmetry, because that's the way squares fit together. Similarly, water moecules tend to fit together so as to form six-sided shapes, and the six-sided shaes fit together in all sorts of patterns, but they're all going to show six-fold symmetry.

The predeterined spaces are predetermined by the first few tiles/water crystals, just like the article said.

[XJETGIRLX]

That makes sense, to account for them all being six sided, but I guess what I don't get is how there's such variety.

I know that there are identical snowflakes, but it seems to me that given my (admittedly lacking) understanding they should all be identical, or at least a lot closer to identical than they are.

Why is this (http://www.snowflakebentley.com/00003.htm) one so much different from this (http://www.snowflakebentley.com/00005.htm) one?

Is it variations in temperature and environment during formation? Or is it just one of those things?

[Amfet]

This site (http://www.its.caltech.edu/~atomic/snowcrystals/faqs/faqs.htm) does a pretty good job of explaining it...

Too late on a Friday afternoon for me to (try) and explain it....

[barbitu8]

Originally posted by XJETGIRLX
I know that there are identical snowflakes, but it seems to me that given my (admittedly lacking) understanding they should all be identical, or at least a lot closer to identical than they are. As Amfet's link states, no two snowflakes are identical. Probably not an absolute truth, but some guy a few years ago made a study of snowflakes, looked at countless of them, and could not find any two that were identical. They are all 6-sided crystals, but they don't crystalize in the same identical shape.

[rowrrbazzle]

Cecil answers the question How can they be sure no two snowflakes are alike?
(http://www.straightdope.com/classics/a3_392.html)

[ultrafilter]

Snowflake formation is probably a good example of a chaotic process, if you know what that means.