Role of face-to-face lecturing in large enrollment physics classes
The introduction of active learning into physics education at the university level may be crucial for improved learning outcomes. In UNIST (Ulsan National Institute of Science and Technology), introductory physics has been redesigned to reduce the time spent on unidirectional lectures, while increasing the time devoted to classroom activities which facilitate the interaction between students and the instructors, as well as increasing the interaction between student peers. We measured student achievement and the degree of student satisfaction in order to evaluate the impact of the new learning methods on student learning outcomes. In the first semester, we redesigned a class of N_I = 176 students with a reduction in lecture hours and replaced them with pre-class self studies and in-class problem solving, and compared it with the traditional lecture based class of N_II = 161 students. We found that even though the midterm results of two classes were similar, the final average score of the redesigned class was 10 points higher than the traditional class. In the second semester, we applied our strategy to three classes but controlled the proportion of face-to-face lectures to the entire class meeting hours systematically to be 1/3 in `Class 1' of N1 = 160 students, 1/2 in 'Class 2' of N2 = 176 students and 2/3 in `Class 3' of N3 = 177 students. (Abridged)