Why do water pipes burst, and why do they always fail the same way? These are two interesting questions.
Water pipes burst because the water inside them expands is it gets close to freezing, and this causes an increase in pressure inside the pipe. When the pressure gets too high for the pipe to contain, it ruptures.
We grew up with water all around us and so this expansion phenomenon seems natural, but interestingly, it is a chemical anomaly. Most liquids do not expand just before transition to solid. You should be thankful for this; it is one of the reasons that life exists.
When a liquid cools the molecules slow down (temperature really is just a measure of the average kinetic energy of the molecules). This slowing down allows the molecules to get closer together and increases the density of the liquid. This happens with water too, and when water is cooled down, it gets denser and denser, down to 3.98°C then, something interesting occurs; it starts to expand again.