Macromolecular Systems I & II           cmclogo.gif (7533 bytes)   


News of 05/15/00

  • I finished grading all your stuff!  Check outside my office.  You should pick up your stuff and keep it for future reference.  (Maybe someday you can teach a better class based on these notes.)
  • Answers to Problem Set #7 are available outside my office also.  Most of you kinda botched the sedimentation analysis.  When you are given log(x/y) to plot, it often is better to just plot log(x) so any error in y doesn't propagate.  Then log(y) just becomes an intercept.  I think (but did not try to prove) that this type of problem prevented most of you (you all worked together, right--sure looked that way!) from obtaining good equilibrium answers.  Most had the right idea on sedimentation velocity, but many of you  could not get the radial frequency (omega) right. 
  • In Problem Set #6, some of you didn't get dn/dc right.  This is important--also easy!  Also, most of you botched problem 9 on friction factors.  Again, you copied too much from each other on this.  I think no one did #6 (radius of gyration/hydrodynamic radius for tetramers) right but since most of you didn't really detail your answers, it was hard to tell.  Perhaps someone will work through my solution, which is certainly the right strategy, to see if there are math errors. 
  • A proof (e.g. of Bragg's law) consists of figures, yes, but also text and logical arguments! 
  • I was unable to really test all your VB files, since you have to provide ALL the files on the disk. 
  • I graded leniently on the programming--most of you tried hard, and some of you succeeded. 
  • Answers to Set #5 are now available--see "Downloads" and choose VB Downloads which contains a zipped file for you to try. 
  • My responsibility to your education doesn't end with the class.  So....if you have questions about these problems, please see me.  It would seem that this would have been a wiser strategy than relying on your classmates for advice. 
  • Also, I am willing to continue helping you with experiments. 
  • I enjoyed the class--have a good summer.