Hot and cold: defining and measuring temperature

Despite the economic importance of temperature measurement and 300 years of scientific research into thermal phenomena, temperature remains one of the least understood and most difficult to measure of all physical quantities. Indeed, our current ability to measure temperature in accordance with thermodynamics fails to meet our needs. This review paints a broad overview of temperature measurement, with insights into the evolution and meaning of the concept of temperature, the structure of different temperature scales and their limitations, the most accurate primary measurement techniques, the International Temperature Scale of 1990, and speculations on future developments.

Automated summary

Despite 300 years of scientific research, temperature measurement remains one of the most difficult and least understood physical quantities. This review provides insights into the evolution and significance of temperature concepts, the limitations of different temperature scales, accurate primary measurement techniques, the International Temperature Scale of 1990, and speculation on future developments.