law / principleof centrifugation
A centrifuge is a piece of equipment, generally driven by an electric motor that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis. This process is called centrifugation. A centrifuge is also used to separate the components of blood in blood banks, to separate components of mixtures say colloids etc in chemical labs.
The centrifuge works using the sedimentation principle, where the centripetal acceleration causes denser substances to separate out along the radial direction (the bottom of the tube). By the same token lighter objects will tend to move to the top of the tube.