Centrifuges use the physical principle of mass inertia to separate substances. Accordingly, the substances migrate outward due to their different densities in the vessel as a result of the centrifugal force that occurs. Depending on the loading quantities and rotor type, such as fixed-angle rotor or swing-out rotor, substances can be separated to varying degrees. Tempering by means of cooling units also makes it possible to separate biological sample material gently. In addition to benchtop centrifuges for smaller substance quantities, floor-standing centrifuges are used for large loading quantities to achieve strong gravity fields (x g). Programmable centrifugation sequences allow reproducible results.