Whe have all heard that no two snowflkes are exactly alike. Last night my wife asked me how do we know this for a fact. With all the billions and billions of snowflakes that have fallen to earth since the begining of time there must be some that are identical. Who determined this to be fact..is it fact or is it a tale. Is ther a mathmatical formula that would either prove or disprove this statement?

She suggested that I pose the question to the brain trust know as the c-bid forum

And so I have

speak freely amongst yourselves and reply with any information pro or con that you may have

Sounds like a job for 'Myth Busters' . . .

that is COMPLETE horsecrap.

last week I found three that were exactly the same.

This is gonna turn into a fight before post #20!

"Snow crystals form when the temperature of water in the atmosphere drops below freezing point, either because colder air flows in or because the water rises to colder layers of the atmosphere. But that alone is not enough for the water to freeze. It will be supercooled, i.e. below freezing point and without becoming ice, until it encounters something solid to get the crystallisation process going.

Typical snow crystals form around minute particles of dust and quickly grow into hexagonal forms that are several micrometers in diameter (1 micrometer is one millionth part of a meter). The initial hexagonal shape results from the shape of the water molecule (one oxygen atom between two hydrogen atoms with a 104 degree angle between them). The edges or corners of the crystal protrude a little and are thus in more contact with the super-saturated air (see also the answer by the same author to the question How do frost roses form on windows? on the Icelandic Web of Science). This is how arms begin to grow out of the crystals.

The rate of growth of the crystals at this stage is determined by the temperature. In any given temperature range the crystal will grow fastest on one specific plane, and at a different temperature it will grow faster on another plane (direction). As the snow crystal swirls it will be subject to continuous changes in temperature and its direction of growth will be both irregular and will continually change. There are also random imperfections in crystal structure, sometimes more sometimes less, and they can result in the growth taking a different direction from that described above.

It is also a matter of definition when one can say that two objects are the same; e.g. are there two water molecules that are the same? They all have the same chemical symbols, H2O, which means that they are composed of the same elements and have the same chemical attributes. But there can be other isotopes of elements, both of hydrogen and oxygen. Such isotopes vary significantly in mass from the simple form.

If we play a little with numbers we can note that in a typical small snow crystal there are 1018 molecules of water ( which means 1.000.000.000.000.000.000!). One of every hydrogen atoms differs from the others and is called deuterium. In our example that would mean that about 1015 hydrogen atoms in every snow crystal (of 1000.000.000.000.000!) differ from the others. Deuterium occurs at random in the structure and thus adds to the variety of structure of the crystals. Oxygen isotopes are less likely to do this. On their way to the ground, snow crystals usually join with one another to form the snow flakes we all know so well. Snow flakes are often composed of between 2 and 200 crystals.

Though there is certainly a huge number of snow flakes in the world, they are much fewer than the possible forms of such flakes. The conclusion is that it is almost impossible to find two exactly identical snow flakes."

see.....I told you...."almost impossible". Like I said, I found three last week.

Snowflake Gallery: No Two Alike, of Course

http://www.livescience.com/php/multimedia/imagegallery/igviewer.php?imgid=505&gid=35&index=0 

"No Two Snow Flakes Are The Same Shape”

How it started, my hypothesis :

In 1880, as a birthday gift, Wilson A. Bently received a microscope. Combining it

with a camera, he learned to make photomicrographs of snow crystals. (Really cool,

huh?). Having observed that the most interesting snow flakes (stellar) occurred only

during a certain portion of a warm front storm, Bently concentrated his collecting at those

times, ignoring columnar, needle, and plate crystals for the most part. When many of his

photographs were published in Snow Crystals, in 1931, Bently selected the “best looking”

pictures, not a scientific sample, some were retouched. His total collection of Snow

crystal photos was fewer than 6000, not enough to make a snowball.

But, since it’s the kind of amazing “fact” we like to believe, no one questioned the

statement that, “No two snow flakes are ever alike.” Rather they hurried to spread their

wonderful new “knowledge of nature”. And before long it was being taught as fact in

science lessons in elementary schools throughout the land.

Being accustomed to memorizing isolated factoids, few noticed that this assertion implies

a knowledge of every snow flake that ever was and ever will be. Nor did many think of

the statistical improbabilities involved. I have heard those who should certainly know

better try to salvage this myth.

“If you consider their molecular structure, then no two snow flakes are the same shape.”

In that case, no two ping -pong balls are the same shape either. Nor ball bearings . Can you live with that? If so, what’s the point in singling out snow flakes? Why not grains of sand, drops of water, or whatever?

....or cigars.

or boogers.

ick . . .

that snowflake gallery is cool . . .

I don't know. My daughter's day care has a wall with a bunch of snowflakes that all look alike. I'll check tomorrow and report back.

Once again Andy cracks me up.

I personally check them all

Even on a set of identical twins I dated once, I found that no two sets of vulva are exactly alike.

I'm still looking though.

vulvae?

vulvi?

Snowflake? What's a snowflake? You mean like a Sno-Cone?

I'm going to the beach.

thats what y'all call those really pale people who come down from the North and stand ankle deep in the beach water all day.

Nope, we call them yankees.

...and they're fool enough to go swimming when it's freezing outside, like today (60 degrees).