Anna Martin

In the classes that I have been teaching lately, I have had about 20 to 25 students. And usually in every class about 5 to 8 don't participate or start to but then I don't get anything else from them. What would be you suggestions on how to get them more involved? Usually at the end of the first week of class I send a little note to them if I see that they have not participated yet, but it doesn't seem to work for everyone. Should I continue to sending notes each week to a student that has not been participating?