Water is the most common liquid on earth which covers 71.4% of earth surface. It is the only chemical substance on earth that exists naturally in 3 states (solid, liquid and gas (vapors)). But there are some anomalies about water. Unlike most other liquids such as alcohol or oil, when water freezes, it expands by about 9% and due to this expansion pipes break. Normally, if you make something hotter, it vibrates more and tends to occupy more space, and as a result it expands. But in case of water it is not so. The reason for this is due to the strange shape of water.
Water molecule is made up of 2 hydrogen and one oxygen atom and it looks like a mickey mouse head with an oxygen molecule and 2 Hydrogen atom as mickey mouse ears.
Oxygen atom is slightly negative and hydrogen is slightly positively charged so water molecules tend to stick together forming hydrogen bonds. And because of that shape of the molecule the water molecules tend to link together in a very open structure with big holes. This means that there is quite a lot of extra empty space when water freezes, it releases energy because lots of extra bonds can be made. But it does take up more space. And so, ice expands when it freezes.