3. Student group demonstration. This method can occasion: has the advantage of more actively involving students. The group approach can be used to advantage if students are allowed to select their group members. The teacher should evaluate the group as a whole and assign the same grade to each group. The groups will form at first among friends. However, if some of the members are not productive, they will be rejected the next time groups are selected. The peer pressure to produce and become actively involved replaces the necessity for a teacher to encourage students to work. This group arrange- ment may also be effective in organizing labora- tory work. The only problem is that the teacher must be patient until group pressure is brought to bear on the nonproductive students in the class.