Yes, conservation of energy is indeed a fundamental law of physics known as the principle of energy conservation. It states that the total amount of energy in an isolated system remains constant over time. In other words, energy cannot be created or destroyed, but it can be converted from one form to another or transferred between different objects or systems.
The law of energy conservation is based on extensive experimental evidence and is a fundamental principle in various branches of physics, including classical mechanics, thermodynamics, and quantum mechanics. It has been tested and validated in numerous experiments, and its validity holds true under a wide range of physical scenarios.
However, it's important to note that there are situations where it may seem as if energy is not conserved. For example, in certain processes involving subatomic particles, energy can appear to be "created" or "destroyed" due to the conversion of mass into energy (according to Einstein's famous equation E=mc^2) or the production of particles and antiparticles. However, when considering the total energy of the entire system, including all particles and fields involved, energy conservation remains valid.
While the principle of energy conservation is considered to be inviolable within our current understanding of physics, it's worth noting that our understanding of the universe is constantly evolving. New discoveries and insights may lead to modifications or refinements of existing theories. Nonetheless, energy conservation has proven to be an exceptionally robust principle and has consistently held true in a wide range of physical phenomena.