A single water particle (a molecule) is made up of two hydrogen atoms
bonded to an oxygen atom. The oxygen will attract the negative charges in the
hydrogen towards it. This will cause the oxygen atom to be negatively charged
and the hydrogen atoms to become positively charged. When a liquid freezes,
liquid particles move closer together and form strong bonds with one another.
There are now more particles in the same area, the solid is denser than the
liquid. When water freezes the negative charges on the oxygen push the
particles apart. This means that the water becomes less dense with freezing.
