International Temperature Scale of 1990 International Temperature Scale of 1990 The International Temperature Scale of 1990 (ITS–90) published by the Consultative Committee for Thermometry (CCT) of the International Committee for Weights and Measures (CIPM) is an equipment calibration standard for making measurements on the Kelvin and Celsius temperature scales. ITS–90 is an approximation of the thermodynamic temperature scale that facilitates the comparability and compatibility of temperature measurements internationally. It specifies fourteen calibration points ranging from 0.65±0 K to ±0 K (−272.50±0 °C to ±0 °C) and is subdivided into multiple temperature ranges which overlap in some instances. ITS–90 is the latest (as of 2014) of
Planck temperature scale Planck temperature scale The Planck temperature scale is an absolute temperature scale using natural units. On this scale, 0 is absolute zero, and 1 is the Planck temperature. Quantum Theory states that the Planck temperature is the hottest possible temperature. The symbol used for this scale is "T". The freezing/melting point of water on this scale would be written 1.928 × 10"T". A way of expressing temperatures in more familiar sized units is to use centimicroyocto plank temperatures (cµy"T"). The freezing point of water is 1.928 × 10"T". By simply moving the decimal point 32 places to the right, you