why is ice lighter than water?

[jkw1 at axe.humboldt.edu]

In article <Pine.SOL.3.92.960617152153.26044A-100000 at hsc.usc.edu>, cchoi at hsc.usc.edu 
says...
>
>Hi, I am taking a biochem 101A now.  If any of you out there can explain
>why the density of ice is lighter than liquid water, it would be great
>help to me.
>I know the problem is related to the bond length of hydrogen bond, but I
>cannot fully understand the concept.
>help me.
>
>
The bond angle is more relavent here. The density of water is greatest at 4 deg. C so 
therefore ice which is at 0 deg. C is lighter than the surrounding water and it floats. The 
hexagonal shape of ice crystals (and the related weird density configurations) is related to the 
H-O bond angles indirectly.  I think this is it but I havent had my java yet .