Svedberg

The unit is named after the Swedish chemist Theodor Svedberg (1884–1971), winner of the 1926 Nobel Prize[2] in chemistry for his work on disperse systems, colloids and his invention of the ultracentrifuge.

The S value depends on the frictional forces retarding its movement, which, in turn, are related to the average cross-sectional area of the particle.

A substance with a sedimentation coefficient of 26S (26×10−13 s) will travel at 26 micrometers per second (26×10−6 m/s) under the influence of an acceleration of a million gravities (107 m/s2).

[b] Centrifugal acceleration is given as rω2; where r is the radial distance from the rotation axis and ω is the angular velocity in radians per second.

[1] In centrifugation of small biochemical species, a convention has developed in which sedimentation coefficients are expressed in the Svedberg units.