Ultracentrifuge Rotor
date: label: date made
content: 1947
notes: label: Description (Brief)
content: This rotor was the workhorse behind an ultracentrifuge used in the Chemistry Department at the University of Wisconsin–Madison from the 1930s through the 1950s. Invented by Swedish chemist Theodor Svedberg in the mid-1920s, the ultracentrifuge was originally developed to analyze the weight of large molecules like proteins. Today it is commonly used to separate out molecules in solution.
label: Description (Brief)
content: Although based in Sweden for most of his life, Svedberg spent the spring of 1923 as a visiting professor at the University of Wisconsin, where he developed the optical centrifuge. On his return to Sweden, he modified the centrifuge to have a higher centrifugal field, creating the ultracentrifuge.
label: Description (Brief)
content: The ultracentrifuge works on the principle that heavy molecules sediment out of a solution at a speed relating to their weight. But, gravity alone is not strong enough to cause very light molecules to fall out of solution. To address this, the ultracentrifuge spins rapidly to create a force stronger than gravity, causing particularly light molecules to begin sedimenting out of solution. As the molecules fall, they are photographed. Analysis of these photographs can be used to establish the speed at which the molecules fell. Because that speed is related to how heavy a molecule is, it can be used to determine molecular weights.
label: Description (Brief)
content: Before the introduction of the ultracentrifuge, there was no reliable method for determining the molecular weight of proteins and other large molecules. For this and similar research, Svedberg won the Nobel Prize in Chemistry in 1926.
label: Description (Brief)
content: Sources:
label: Description (Brief)
content: “The Analytical Ultracentrifuge: The First Half Century 1924–1974. Part I: Svedberg and the Early Experiments.” Pedersen, Kai O. <i>Fraction: News of Biochemical Instrumentation</i>. No. 1. Published by Spinco Division of Beckman Instruments, Inc. 1974.
label: Description (Brief)
content: “The Analytical Ultracentrifuge: The First Half Century 1924–1974. Part II: From the Colloid Experiments to DNA.” Williams, J.W. <i>Fraction: News of Biochemical Instrumentation</i>. No. 1. Published by Spinco Division of Beckman Instruments, Inc. 1974.
label: Description (Brief)
content: “Centrifuge, Ultra-.” p. 95. <i>Instruments of Science: An Historical Encyclopedia</i>. edited by Robert Bud and Deborah Jean Warner. Taylor & Francis. 1998.
label: Description (Brief)
content: Accession File
label: Location
content: Currently not on view
place: label: used
content: United States: Wisconsin, Madison
topic: label: Subject
content: biochemistry
label: Subject
content: Chemistry
label: Subject
content: Nobel Prize
setName: label: See more items in
content: Medicine and Science: Chemistry
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content: Biotechnology and Genetics
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content: Science & Mathematics
creditLine: label: Credit Line
content: Gift of University of Wisconsin
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: CH.337002
label: catalog number
content: 337002
label: accession number
content: 1979.0188
objectType: label: Object Name
content: rotor
physicalDescription: label: Physical Description
content: stainless steel (overall material)
label: Physical Description
content: pine (overall material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: rotor: 12.5 cm x 18.8 cm x 15.7 cm; 4 15/16 in x 7 3/8 in x 6 3/16 in
label: Measurements
content: shipping case: 39 cm x 21 cm x 22 cm; 15 3/8 in x 8 1/4 in x 8 11/16 in
label: Measurements
content: overall in case: 8 3/4 in x 15 1/4 in x 8 1/4 in; 22.225 cm x 38.735 cm x 20.955 cm