Temperature for zero temperature, according to the third law of thermodynamics. Nevertheless, a Kelvin temperature does in fact have a definite numerical value that has been arbitrarily chosen by tradition and is dependent on the property of a particular materials; it is simply less arbitrary than relative "degrees" scales such as Celsius and Fahrenheit. Being an absolute scale with one fixed point (zero), there is only one degree of freedom left to arbitrary choice, rather than two as in relative scales. For the Kelvin scale in modern times, this choice of convention is made to be that of setting the gas–liquid–solid
Wedgwood scale The scale was divided into 240 equidistant parts. The unheated piece of clay would fit the 0.5-inch gap giving the zero temperature reading. After annealing, the clay cylinder would shrink and fit somewhere in between the left and right ends of the bars, and the temperature could be read from the scales on the bars. The origin (0°) on Wedgwood scale was set at the onset temperature of red heat, . The scale had 240 steps of and extended up to . Wedgwood tried to compare his scale with other scales by measuring the expansion of silver as a function