I think that if it interesting and insightful, entertaining and or useful to people, then I would say go for it. I write recipes, stories and fan fiction for my hub, and I have found that generally people like reading what I have posted.
To me hubs are about what interests you, and something that you might think others may enjoy reading. College work in particular would be a great idea so that other students who may be taking the same class or course can read your notes and be able to use it for their own research.
Good luck, and good question.