Here's why:
* 0 degrees Celsius is the freezing point of water. This is a specific property of water, not a universal rule for all matter.
* Different substances have different freezing points. For example, iron freezes at 1538 degrees Celsius, while helium freezes at -272.2 degrees Celsius (just a few degrees above absolute zero).
It's important to remember that freezing is the process of a liquid turning into a solid. Each substance has its own unique temperature at which this change of state occurs.
