Leiden scale to be true. Oxygen under a standard atmosphere boils at a temperature in the 90.15 to 90.18 K range. For hydrogen, it depends on the molecular variety. The boiling point is 20.390 K for "normal" hydrogen (made up of 75% orthohydrogen and 25% parahydrogen) and 20.268 K for pure parahydrogen. Under the purported definition, absolute zero would lie at -20.15 °L. Leiden scale The Leiden scale (°L) was used to calibrate low-temperature indirect measurements in the early twentieth century, by providing conventional values (in kelvins, then termed "degrees Kelvin") of helium vapour pressure. It was used below -183°C, the starting
Thermodynamic temperature heat (to avoid logic loop, we should first define entropy through statistical mechanics): For a system in which the entropy "S" is a function "S"("E") of its energy "E", the thermodynamic temperature "T" is therefore given by so that the reciprocal of the thermodynamic temperature is the rate of increase of entropy with energy. Thermodynamic temperature Thermodynamic temperature is the absolute measure of temperature and is one of the principal parameters of thermodynamics. Thermodynamic temperature is defined by the third law of thermodynamics in which the theoretically lowest temperature is the null or zero point. At this point, absolute zero,