Here's why:
* Kelvin (K) is an absolute temperature scale, meaning it starts at absolute zero (the theoretical point where all molecular motion stops).
* Celsius (°C) is a relative temperature scale, where 0°C is the freezing point of water.
* 273 K is equivalent to 0°C.
Therefore, 273 K is the temperature at which water transitions from its liquid state to its solid state (ice).
