When frozen, water molecules take a more defined shape and arrange themselves in six-sided crystalline structures. The crystalline arrangement is less dense than that of the molecules in liquid form which makes the ice less dense than the liquid water. When water freezes, the volume expands by approximately 9%.

Do liquids expand when frozen?

Actually, most liquids do /not/ expand when they freeze. In fact, most liquids lose volume as they freeze. This is because when you freeze a liquid, its molecules slow down. ... When the individual molecules become closer together, the substance will take up less space.

Why does water expand when it freezes?

When water freezes solid, at 32 degrees, it expands dramatically. ... Each water molecule is two hydrogen atoms bonded to one oxygen atom (H2O). The H2O molecule's slightly charged ends attract the oppositely charged ends of other water molecules. In liquid water, these "hydrogen bonds" form, break, and re-form.