What energy is, appears evident to most of us. This is different with its counterpart entropy. Entropy, however, explains much of our everyday life, as well as basic processes in physics and biology. It is worth to be understood. Here, I explain the most basic facts about entropy. Two Levels Define Entropy: Micro Level and Macro Level The scientific physical definition of entropy characterises it as a difference between two levels: a detail level and an overview level. Example Coffee Cup The thermal entropy according to Boltzmann is classic, using the example of an ideal gas. The temperature (1 value)