Stokes' law describes the motion of small spherical particles as they move through a viscous fluid. It states that the force of viscosity acting on a particle is proportional to the particle's radius, the fluid's viscosity, and the particle's velocity. This relationship helps predict how quickly a particle will settle in a fluid. The law is named after the British scientist George Gabriel Stokes, who formulated it in the 19th century. Stokes' law is essential in various fields, including physics, engineering, and biotechnology, as it aids in understanding sedimentation, filtration, and the behavior of aerosols.