Hydrogen bond

They engage in additional kind of loose relationships with other neighboring hydrogen and oxygen atoms.

These loose, somewhat fleeting relationships are called hydrogen bonds.

In ice, 100% of O and H atoms are involved in hydrogen bonding.

The most energetically favorable spatial arrangement of these bonds actually pushes the water molecules apart a bit, resulting in the volume of ice being 10% larger than the volume of water, which is really weird for solids and liquids.

And also why hockey was invented,

and why soda bottles explode when you leave them in But

hydrogen bonds are also why taking a warm bath is so great, why steam engines change the world, and why temperatures on our planet are so constant when compared to other cosmic temperature fluctuations.

It takes a lot of energy to change the temperature of water because each little temperature change is associated with breaking or forming lots of hydrogen bonds.