Talk:Svedberg

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[edit] Error found

From an email to helpdesk:

"Your Wikipedia article entitled "Svedberg" states that "The sedimentation rate or coefficient of a particle or macromolecule is computed by dividing the constant speed of sedimentation (in m/s) [i.e., in meters/second] into the acceleration applied [(in m/s/s)]." The actual mathematical expression that was included within the second set of parentheses in the preceding sentence is the expression that one would read aloud as "meters per second squared." This e-mail program does not enable the user to type a superscript "2" after the "s" in the denominator, so this user typed "m/s/s." However, if one divides the speed of sedimentation, m/s, into the acceleration applied, m/s/s, one obtains 1/s instead of s. The article says that "The result [of the division] has the dimensions of a unit of time and is expressed in svedbergs." The article says that one svedberg is exactly 10 to the minus 13 power s. Again, this e-mail program does not enable the user to type superscript symbols. If a svedberg is expressed in s, a svedberg cannot be calculated by dividing m/s into m/s/s. Would you please clarify and/or correct the stated method of computing the sedimentation rate or coefficient of a particle or macromolecule?" --James W. Frederiksen, MD

Someone please give the correct derivation. --maru (talk) contribs 06:01, 27 January 2006 (UTC)

The equation is s = v/(W^2 r)

where v is velocity of sedimentation

     w is rate of rotation
     r is distance from the axis of rotation

The dimensions can be calculated from this, but im not certain about the units —Preceding unsigned comment added by 84.71.66.130 (talk) 09:14, 3 April 2008 (UTC)

[edit] Incomprehensible

This page is nearly incomprehensible -- and I am a professional physicist! I will attempt to clean it up in the near future, but in the short term, can someone make it clear whether, in the first paragraph, the Svedberg is 10 ^{− 13} s, or whether it is on the order of 10 ^{− 13} s or whether it is conventionally reported in units of 10 ^{− 13} s? I think it must be on the order of 10 ^{− 13} s. -- David W. Hogg 21:45, 20 April 2007 (UTC)