1. Temperature and thermal energy

1.1 Temperature-energy relationship

Temperature metrology, obviously one of the most useful of all, is an extraordinary illustration of the need for fundamental, rational understanding of phenomena that are often first apprehended by our senses. The notion of "temperature" is commonly associated with that of hot and cold. Indeed, the first "thermoscopes" were graduated into "very hot, hot, temperate, cold and very cold" ranges [1] [2] [7] .

In thermodynamics, temperature was introduced in 1824 with the notion of a "perfect thermal...