The First Law, in its generalized sense, is a statement of the conservation of energy and matter. It posits that energy can never be created or destroyed, but it can be transformed from one form into another. This implies that the total energy of an isolated system remains constant over time. The first law tells us about the flow of energy within any physical system and that we can trace its transformation from one form to another throughout the system. The First Law is one of the most fundamental ideas within all of modern science, the conservation laws that it expresses has far-reaching implications as symmetries of nature which we do not see violated. They serve as a strong constraint on any theory in any branch of science.