An energy barrier is a threshold that must be overcome for a chemical reaction or physical process to occur. It represents the minimum energy required to transform reactants into products, allowing them to transition from one state to another. This concept is crucial in fields like chemistry and physics, as it helps explain reaction rates and stability. In many cases, energy barriers can be lowered by catalysts, which are substances that speed up reactions without being consumed. Understanding energy barriers is essential for developing new materials, optimizing industrial processes, and studying biological systems, such as enzyme activity in living organisms.