You ask the following: Is there an optimal number for students in the classroom?
What follows is a short answer. As I see it, the number of students in the classroom depends on many facotors. Maybe the most important is the type of school. At pre-primary, primary, and secondary schools I think, as a psyschologist, that about 20 students in the clasroom is OK. At the undergraduate level, the number of students per classroom tends to be bigger. As a university professor, at this level a had classrooms with more than 100 students. At the graduate level (Master and Ph D), I think that the optimal number for students in the classrom shoud range between 8 and 15 students per classrom. In the case of handicaped students, the less the number of students per classrom, the more is good for the focal students.
There are many factors. The subject matter and instructional methodology are two of the most important, I think.
Constructionist student-centered active learning classrooms generally need fewer students than lecture-memorization instructional design.
Your question about affective learning implies smaller class size, such as 15-20. But many schools want class sizes that are larger than this because they get more tuition income per teacher.
Affective learning presupposes a highly interactive atmosphere whereby the teacher and particular groups of learners establish a friendly rapport for attaining the targeted outcomes. Consequently, class size plays a pivotal role in creating an appropriate method of communication because when dealing with learners, teachers should remember that they are dealing with creatures of emotion. As such, a small class size can pave the way for catering to such emotions.
It depends on the subject being taught, in my opinion. If language is being taught, for instance, 5 to 12 students is the closest to ideal, from my own experience. If other subjects are being lectured that do not depend on a high level of interaction among students, 20 to 30 students look like a sound number, I reckon.
Hazim Al Dilaimy , 15 to 20 students would be suitable for teaching subjects that require practical activities. For other theoretical fields I think 30 will be pretty enough for better class management and higher students' engagement.
it depends on the subject teaching person (faculty.) if faculty is perfect with his subject then teaching also very interesting all students in the class room may understood easily either intelligent fellow or average fellow