E=mc^2 expresses the principle of mass-energy equivalence, indicating that mass can be converted into energy. The formula states that energy (E) equals mass (m) multiplied by the speed of light (c) squared, highlighting how even small amounts of mass can generate substantial energy. For example, a hydrogen atom, despite its tiny mass, can yield a large energy value when calculated using this equation. This concept illustrates the potential energy contained within matter, emphasizing the relationship between mass and energy. Understanding this principle is crucial for grasping fundamental physics concepts.