is a flash file made from a short molecular dynamics simulation
of water. The green lines represent hydrogen bonds between oxygen
and hydrogen. Notice the tight structure of water
bonds are much weaker than covalent bonds. However, when a large
number of hydrogen bonds act in unison they will make a strong
contributory effect. This is the case in water shown here.
Liquid water has a partially ordered structure in which hydrogen
bonds are constantly being formed and breaking up. Because of
the short time scale (on the order of a few picoseconds) few bonds
are seen breaking.