The fundamental principle of thermodynamics stating that energy disperses is known as the second law of thermodynamics. It addresses the concept of entropy, which describes the measure of disorder or randomness in a system. According to this law, in any energy exchange, if no energy enters or leaves the system, the total entropy will increase over time, reflecting a natural tendency for systems to evolve toward thermodynamic equilibrium. This principle is crucial for understanding energy transformations and the directionality of natural processes.