|snowflake photos by Wilson Bentley|
A water molecule is made up of two hydrogen atoms attached to one oxygen atom. The hydrogens repel to get as far away as possible from each other, but because of the configuration of the electrons around the oxygen, a water molecule isn't just a straight line.
|water molecule from Chemical Forums|
The crosses and dots represent electrons. The pairs of electrons are all negative,
so repel to get as far away as possible from each other.
Water molecules can form hydrogen bonds between themselves, which accounts for many of the characteristics of water. A hydrogen is attracted to the lone pair of electrons on the oxygen of a different molecule. One water molecule can form hydrogen bonds with four other molecules to form that crucial tetrahedral shape. Together, the molecules of water in ice form a tetrahedral structure.
|structure of ice from 800 Main Street|
|To fold a scientifically correct snowflake, once you've folded your circle of paper in half,|
instead of folding it in half again, fold it into thirds.