Second, a process takes place and it always goes in one direction, from hot to cold. Heat is, of course, only one manifestation of energy, but it will provide us with a model for all forms of energy. A simple analogy of the second law is known as the Cosmic Sink. Water, for which read energy, always runs downhill. Uphill can be read as hot and downhill as cold.
Heat is active energy and cold is the absence of energy.
It is all trying to reach a uniform and colder level. The effort required to raise water to a particular level, such as a municipal water tank, is stored as the potential energy of the water running out of the tank. It contains some quantity of energy in a potential state. As the water is released the potential energy is consumed. The state of non-energy created by this release is entropy.