Water becomes frozen (one may also use the term "solid" to the frozen liquids) at 0 degrees Celsius. The difference between the boiling and the freezing points is equalโ€ฆto 100 degrees! When Anders Celsius devised his temperature scale, he intentionally chose those numbers because it was easy to remember, based on the boiling and freezing points of water!Simple and easy to remember!

There is also an interesting term known as an "absolute zero". It is -273.15 degrees Celsius.