2-The International Temperature Scale was first adopted by the International Committee on Weights and Measures in 1927 to provide a global standard for temperature measurement. This scale has been refined and extended in several revisions, most recently in 1990 (International Temperature Scale of 1990, ITS-90). What are some of the reasons for revising the scale? What are some of the principal changes that have been made since 1927?

2-The International Temperature Scale was first adopted by the International Committee on Weights and Measures in 1927 to provide a global standard for temperature measurement. This scale has been refined and extended in several revisions, most recently in 1990 (International Temperature Scale of 1990, ITS-90). What are some of the reasons for revising the scale? What are some of the principal changes that have been made since 1927?