ITS90lämpötilamonikatyylikarttaa

ITS90lämpötila refers to the International Temperature Scale of 1990, which is the current standard for measuring temperature. It is an empirical scale, meaning it is based on a set of experimentally determined fixed points and interpolation procedures. These fixed points are temperatures at which pure substances undergo phase transitions, such as melting or boiling, at a defined pressure. Examples include the triple point of water and the freezing points of various metals.

The ITS90 is designed to provide a practical and reproducible way to define temperature scales that closely approximate the thermodynamic temperature scale (Kelvin). It is divided into different ranges, each with specific defining fixed points and standard thermometers used for interpolation. For instance, resistance thermometers are commonly used in the lower temperature ranges, while thermocouples are employed at higher temperatures. The ITS90 is crucial for scientific research, industrial processes, and calibration of temperature measuring instruments, ensuring consistency and accuracy in temperature measurements worldwide. Its development aimed to improve upon previous temperature scales by providing better continuity and accuracy, particularly at low temperatures.