Theodor Svedberg, Swedish physical chemist, c 1940s.
© Science Museum / Science & Society Picture Library
Theodor Svedberg (1884-1971) spent the majority of his professional life at the Chemical Institute at Uppsala, Sweden. Svedberg is best known for developing the ultracentrifuge, which he used to study sedimentation. An ultracentrifuge separates molecules using a powerful centrifugal force (much above gravity) to 'pull down' large molecules, such as proteins. Svedberg won the Nobel Prize for Chemistry in 1926. The unit of sedimentation velocity, the svedberg (S), is named after him.