| the particular temperature and pressure at which the solid, liquid, and gaseous phases of a given substance are all at equilibrium with one another. |
| triple point n. The temperature and pressure at which a substance can exist in equilibrium in the liquid, solid, and gaseous states. The triple point of pure water is at 0.01 degrees Celsius and 4.58 millimeters of mercury and is used to calibrate thermometers. |
In physics, the temperature at which all three phases of matter (solid, liquid, and gas) for a given substance can coexist.
Note: The triple point for water is a little above the freezing point, and is used to define temperature scales.
triple point n.
The temperature and pressure at which three different phases, such as gaseous, liquid, and solid phases, of a particular substance can coexist in equilibrium.
| triple point
The temperature and pressure at which a substance can exist in equilibrium in the liquid, solid, and gaseous states. The triple point of pure water is at 0.01°C (273.16K, 32.01°F) and 4.58 mm (611.2Pa) of mercury and is used to calibrate thermometers. Compare critical point. |