Lectures help to structure the courses and describe for students the central aspects of the subject, present special problem areas, etc. Classes are probably the most common type of teaching today. Classes are held for groups of twenty to thirty students, and their purpose is for the students and teacher to discuss and work through the course literature. Laboratory sessions are becoming increasingly common, especially in the natural sciences and in technology. In a lab session, students work alone or in small groups on an experimental assignment, and then generally submit a written report of the results.
Seminars are a type of teaching largely dependent on active student participation.
Seminars are held, for example, to go through project work. Group work is also quite common in some subject areas. Student groups work independently on an assignment, but generally have access to a teacher for guidance. Tutorials are given to individual students or small groups. At a tutorial, the teacher in charge of a course helps to prepare the students for their oral presentations or reports and to plan their term papers and essays.