Thermal Physics is one of the fundamental fields of learning in the curriculum of any sound training in Physical Sciences. Many of the concepts working in this division of Physics have also each day homonyms. Consequently, it is always tempting for opening students to overuse intuitive shortcuts in dealing with sensible problems and to think with vulgar influence. Though, while perception is definitely a fundamental tool for a physicist, it must clearly rely on a solid conceptual conditions. The key concepts are carefully obtainable in a clear way, and new ideas are illustrated with copious worked as a description.