eli5: If absolute 0 is only theoretical, how do we know what it is in Celsius and fereignheit

Question

eli5: If absolute 0 is only theoretical, how do we know what it is in Celsius and fereignheit

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Answer 1

Temperature is a measure of the average kinetic energy of the atoms or molecules in the system. The absolute temperature is proportional to the average translational kinetic energy of the atoms of molecules. We define 0 Kelvin as the temperature where kinetic energy is 0.

There is a formula for calculating temperature from the kinetic energy, for gas this formula is ½m<v2> = (3/2)kBT