What is thermodynamics scale?
The thermodynamic temperature scales are based on the third law of thermodynamics:The entropy of a system approaches a constant value as the temperature approaches zero. The entropy of a system at absolute zero is typically zero, and in all cases is determined only by the number of different ground states it has.The two commonly used thermodynamic temperature scales are Kelvin (K), which has temperature increments the same size as Celsius and Rankine (°R), which had temperature increments the same size as Fahrenheit.The thermodynamic temperature scales are further defined by extrapolation of the values PV at given temperatures as pressure approaches zero and thus the ideal gas law becomes a better and better approximation.