Ball bearings are small, spherical objects made of metal or ceramic that help reduce friction between moving parts in machines. They allow for smooth rotation and movement by providing a surface for parts to roll against, rather than slide. This design improves efficiency and extends the lifespan of machinery. These components are commonly found in various applications, including bicycles, cars, and industrial equipment. By enabling smoother motion, ball bearings play a crucial role in enhancing performance and reducing wear and tear on mechanical systems.