ABSTRACT
Thermodynamics stands unique compared to mechanics and electromagnetics since it focuses directly on “dispersion” that necessarily takes place in actual macroscopic phenomena. All of the mechanical and electromagnetic phenomena that we experience in everyday life can never escape from thermodynamic phenomena, that is, the dispersion of heat and matter involved. This chapter describes the relationship between work and heat established in the mid-19th century by Joule and others. It defines dispersion, entropy and absolute temperature. The concept of temperature is the primary index to signify the vigour with randomness of the molecular motion within a certain body, whether it is either in solid, liquid or gas state. A certain amount of dispersion inevitably emerges in the course of energy transfer from work to heat. The chapter shows the relationship between pressure and volume, often called P-V diagram, of air as an ideal gas used as the working fluid in a small Carnot engine.
