Posted by Dan Anderson on June 19, 2002 at 13:54:05:
In Reply to: Re: snowflakes posted by Duncan on May 23, 2002 at 10:11:44:
molecules such as water can exist in three phases, gas, liquid or solid. in the solid form, molecules may be randomly oriented or ordered. an example of this is silicon dioxide whin in a disordered solid is glass but when the molecules all bear the same orientation with respect to their neighbors, it is quartz.
furthermore, many molecules can have more than one solid crystaline form. these are called polymorphs and have different properties as well. these submicroscopic molecular orientations affect the macroscopic shape of the crystal. thus different polymorphs have different shapes.
water has only one polymorph i'm aware of. it is fairly unique because it leaves a lot of empty space between molecles. this is why ice floats in water while almost every other solid sinks is mre dense than it's liquid form. it is true that the water molecules orient themselves into shapes that look like tiny hexagons. however, it is not always and is in fact rarely true that a macromolecular crystal bears any relation to it's crystal packing structure or crystal lattice. in this case the similarity i believe to be a red herring.
the hexagonal shape of the flakes is a dead give away that all ice crystals are of the same polymorph, however. it is an exciting observation indeed.
Post a Followup