A centrifuge is a device that typically separates substances of different densities or solid particles in a liquid based on their densities by spinning them at different speeds. Separation with a centrifuge is based on the principle of separating particles in suspension with a force and speed greater than the force of gravity. During the centrifuge process, the settling rate depends on the shape, density, applied force, and density of the environment of the particles, and appropriate device and rotor selection are made accordingly.