I think that it is important to assign some homework several times per week. Some of these assignments are practice with what I taught that day and sometimes they are in preparation for the following day, e.g. prelabs, etc. Unfortunately, I have several students in each period that just aren't doing the homework. Help me!
I think this is a good idea.
Or a pizza party at the end of the week!
I would try to incorporate more assignments that interest the kids.