Abstract

• The primary purpose of this study was to examine the effects of whole-class discussion on the achievement of Grade Nine science students. Having the participants of non-randomization, the nonequivalent control group design which is one of the quasi-experimental designs was employed here. Firstly, two intact classes from BEHS-Budalin and BEHS-Nyaung Gan were randomly assigned as experimental and control group. Both groups were then pretested, and the results were analyzed by independent samples t test to examine the initial group equivalency. The results showed a significant difference in the performance of the two groups. During the fourweek’s treatment, the two classes were conducted to be essentially identical other than teaching method used, covering the same topic area, using the same text- related materials; in particular the same teacher taught in the same amount of time. While the experimental groups were received a treatment of whole-class discussion, the control groups were of general teaching strategy. After the experimental intervention, both groups were post- tested to test the research hypotheses or to compare science achievement of the two groups in each school, and it was analyzed by using analysis of covariance (ANCOVA). A significant difference was found at almost all levels of Bloom’s Taxonomy on posttest items, all favoring the whole-class discussion groups. Hence, it can be clearly seen that students of whole-class discussion demonstrated a significantly higher performance than their counterparts of conventional teaching. In the light of the results, moreover, whole-class discussion was more effective for science teaching than general teaching strategies. Finally, the findings from this experimental study would provide actionable directions or recommendations for teachers charged with teaching general science at lower secondary level in Myanmar.