The concept of entropy is introduced within the context of classical
thermodynamics where it was first developed to answer the questions: What happens
when heat spontaneously goes from hot bodies to cold ones? To figure out this change,
the transfer process must have some peculiar features that make it reversible. First of
all, to be studied, systems and processes must be conceptualised as occurring at
equilibrium conditions, or in conditions close to equilibrium. A first description of
equilibrium is provided.
Keywords: Balancing of forces, Classical thermodynamics, Clausius’ equation,
Dynamic equilibrium, Entropy, Equilibrium conditions, Friction, Heat capacity,
Heat dissipation, Ideal gas, Infinitesimal change, Irreversible process, Isothermal
process, Potentially available energy, Quasi-static process, Reversible process,
Stationary state, Thermal energy, Transfer of heat, Turbulence.
