The law stating that energy can be transferred but not created or destroyed is known as the First Law of Thermodynamics, also referred to as the principle of conservation of energy. This law asserts that energy in a closed system remains constant; it can only change forms, such as from kinetic to potential energy. Understanding this law is fundamental in disciplines like physics, engineering, and environmental science, as it underscores the balance of energy within systems and the need for efficient energy use.