Triple point
From Simple English Wikipedia, the free encyclopedia
The triple point of water or any substance is the combination of temperature and pressure at which it exists in its solid, liquid, and gaseous state all at once, in equilibrium.
The temperature of the triple point of water is a commonly used physical constant which is used to define temperature scales and calibrate temperature-measuring systems.
By definition, the temperature of the triple point of water is 273.16 K, or 0.01 °C.