What one mainly believes is that a substance boils at 100 degree and freezes at 0 degrees. But what if I tell you that at a certain temperature and pressure the substance can boil and freeze simultaneously.
Yes, The point where it happens is called the “Triple point”. In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.
- For example, the triple point of mercury occurs at a temperature of −38.83440 °C and a pressure of 0.2 mPa.
- For water, that triple point is at 32.02°F (0.01°C) and .006 atm.
So, what s actually the use of triple point in our daily life? According to the National Physics Laboratory, “triple points make ideal reference points for the calibration of thermometers.” Additionally, as reported by the NPL, “Ethylene carbonate has a triple point temperature of 36.315°C which, being close to body temperature, makes it a highly useful reference point for the calibration of clinical thermometers, while benzoic acid has a triple point temperature of 122.33°C, close to the sterilising temperature of medical drip solutions.”
To watch a video on the particular topic: https:curiosity.com/videos/science-cyclohexane-at-the-triple-point-tenstone.