Here's what happens:

* Water transitions from a liquid to a solid state. This means the molecules slow down and arrange themselves into a crystal lattice structure, forming ice.

* Density increases. Water expands when it freezes, which is why ice floats.

* Heat is released. This process is called exothermic, meaning it releases energy into the surroundings.

Important Note: While 32 degrees Fahrenheit is the freezing point of pure water, impurities like salt or sugar can lower the freezing point.