Giulio Rubinelli Disney Channel Italia

quantum mechanics

snow is cold, snow is white, snow is a direct manifestation of the laws of quantum mechanics! (Onset = disclosure, publication, visualization)

Our entire world would not exist (or not) if the Put of quantum mechanics were like they are. The chemical properties of elements are determined by the quantum mechanical properties of the electron shell. Why should the basis of snow emerge again very clearly?

enlarged image of a snowflake (Snow_flake_4.jpg from http://www.partow.net/miscellaneous/snowflakes.html ).

It is located on the beautiful hexagonal shape of snow crystals, the bond angle of the water molecule H20 directly reflect. The bond angle of about 104 ° is a direct consequence of quantum mechanical laws. The central oxygen atom absorbs the electrons of the two bonded hydrogen atoms for the most part and is then negatively charged. On the hydrogen atoms in each case remains the positive charge of the nucleus, which consists only of a single proton. The two positive charges of the hydrogen atoms repel each other and to the classical laws would create a linear molecule.

a) Linear molecules such as CO2, b) angled H2O molecule.

However, the quantum mechanical result Bonding orbitals of the central oxygen atom from a superposition of the s and p orbitals and there are so-called sp3 hybrids with binding arms that have a bond angle of 104 °. This is a purely quantum mechanical effect and the only reason why the water some of which particular characteristics that distinguish it as the anomaly at 4 ° C, where it has the largest mass density.

also produced the hexagonal shape of a snowflake out of the bond angle of the water molecule. From the hexagonal geometry of a snowflake can be seen that the angular play of 60 ° and 120 °, a special role. The 104 ° of the bond angle of a water molecule are not the same throughout with the 120 ° in the snowflake. But still, this seems to be the right geometry, so the best possible match is achieved. Either the water molecule in the snowflake will be distorted accordingly, or the emerging solid state is not fully adapted, despite the bond angle in a stable manner.

--------- PS: The ideal bond angle of 109.5 ° of a sp3-orbital corresponds to the angle at which one of the center of the tetrahedron sees two corners. In the water molecule is due to additional interaction (which I do not understand exactly) like this to vary.
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PS_2:
is asked in a comment to this post, why snowflakes vary, each is beautiful in itself but as symmetrical again. I can not answer it as easy as I make some assumptions must be discouraged and a little bit.
It is truly amazing, every snowflake is different, but (almost?), Each snowflake from the center starting at the same places side arms that look all the same again. How does one arm, when produced on the other hand, an arm and now has to grow?
On the quantum mechanics, it is hardly that, in this case does not contribute well over such large distances. It works only so that the next molecule is being grown at the proper angle. But when it then (back in the right angle) side arms are hanging probably from something else.
my opinion, the mechanical stresses in the crystal. The quantum mechanical bond angle is 120 ° but not so soaked with 104 ° but clearly on it. Therefore arise at the juxtaposition of the water molecules to hexagonal ice resulting in mechanical tension. Without this tension would arise probably no snowflakes with the six main arms but simply hexagonal platelets. Only by increasing the size of the inner hexagonal plate tension pulls on the crystal and there are six main branches.
(from science and research is well known that the mechanical stresses the formation of crystalline Layers affect considerably and even control. My colleagues at the Physics Institute set this effect is a very targeted way to nanocrystals produce on surfaces.)
When the main arms emerge from the snow should depend on the temperature, but also by the speed with which the crystal grows, maybe other parameters I see now on (yes, as the degree of pollution of the air with other particles that are more or less be installed). As these conditions but for a few snow flakes all around the same, is the growth of the arms on all sides pretty much the same time. I suspect that it is with the other smaller tributaries Sun When these begin to grow, because the tension is too great in the main arms depends in turn on the environmental conditions, but for a single snowflake again the same at all six corners.
provides for the different snowflakes but different. Even in a cloud, a snowflake in higher altitudes or further down here occur in areas where the air pressure, temperature, humidity, etc. are different and therefore every flake slightly different forms. If you are in the web pictures of snowflakes from different parts of the world compares, then the safe did not arise under the same conditions.