Dictionary

A centrifuge is a piece of equipment, generally driven by an electric motor (or, in some older models, by hand), that puts an object in rotation around a fixed axis (spins it in a circle), applying a potentially strong force perpendicular to the axis (outward). Large centrifuges can be used to simulate high gravity or acceleration environments (for example, high-G training for test pilots). Medium-sized centrifuges are used in washing machines and at some swimming pools to wring water out of fabrics. Many centrifuges are used as laboratory or industrial equipment to separate materials, for example small molecules from large molecules. 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 objects that are less dense will tend to move to the top (of the tube; in the rotating picture, move to the centre). Most materials-separating centrifuges use liquids or a mixture of solids and liquids, but gas centrifuges are used for isotope separation, such as to enrich nuclear fuel.