Whether something is 101-level or a difficult thesis topic often depends on your point of view. Different fields seem to define scalars differently, with the physicists sometimes arguing that the mathematicians have got it all wrong: http://imechanica.org/node/15857
On a related note, I was tremendously impressed with the quality of discussion at imechanica.org. At a glance, it may be the best example of a well-functioning online community that I've ever seen.