The Law of Conservation of Energy states that energy cannot be created or destroyed; it can only change forms. This means that the total amount of energy in a closed system remains constant over time. For example, when you turn on a light bulb, electrical energy is converted into light and heat energy, but the total energy remains the same. This principle applies to various processes in nature and technology, such as in mechanical systems, where kinetic energy can transform into potential energy and vice versa. Understanding this law is crucial in fields like physics, engineering, and environmental science.