While Svedberg is primarily known for his work showing that larger molecules sediment faster than smaller molecules, he nevertheless was involved in some earlier ways to use his invention called the ultracentrifuge. This work was founded in Einstein's heat-capacity equation, which was in part based on the phenomenon of Brownian motion. In brief, smaller molecules diffuse more rapidly than larger ones. Svedberg wondered if this could be seen in the banding of molecules that had undergone isopycnography. So he chose, among many different substances tried, those shown here:

    As can be seen, monomeric glucose does indeed form a much more diffuse band than do polymeric glucose (starch), and the protein pepsin forms a narrow band commensurate with its high molecular weight.

    One of the prevailing misconceptions of the time was that DNA was a tetranucleotide having a molecular weight of about 1300, but this is what happened when someone used Svedberg's technique on several different types of DNA - taken from Bacillus cereus, E. coli and Pseudomonas aeruginosa:

    Thus DNA was found to be a huge molecule - even less diffusive than the rather large molecules of pepsin and starch.