Development, implementation and evaluation of a computer plus talk teaching sequence to improve students' understanding of chemical rate of reaction : a Ugandan case study

This study is the first attempt to develop, implement and evaluate a computer plus talk teaching sequence with the purpose of enhancing 15-16 years old students‘ understanding of chemical rate of reaction concept in Uganda. A total of 247 students aged 15-16 years from two High Schools participated in the study. The experimental class (C&TA) consisted of 108 students, 51 males and 57 females while the comparison class (NTA) consisted of 139, 73 males and 66 females. Based on recommendations in the literature that chemical rate of reaction is a difficult topic to teach and learn, I developed a research-based teaching sequence on chemical rate of reaction using a computer and talk approach, implemented this teaching sequence in Uganda and evaluated this teaching sequence by making comparisons with ‗normal‘ teaching. Research-based teaching is a novel approach to pedagogy in Uganda, so I had to train the experimental teacher for two weeks. The trainings were very important in ensuring that the teacher acquired working knowledge about C&TA prior to the actual implementation in the classroom. The study investigated whether the students who followed the C&TA had better understanding of the difficult areas (also called learning demands): (1) rate of reaction, (2) proper orientation of reacting particles, (3) the relationships between activation energy and chemical rate of reaction, (4) the effect of temperature and (5) the effect of concentration of reactants on chemical rate of reaction. I undertook a quasi-experimental study to assess the C&TA‘s impact. I analysed classroom interactions to inform discussion of what influenced its effectiveness, and inform decisions about whether the C&TA sequence was implemented consistently with its design. The statistical analyses of the post-test scores show that the experimental class (C&TA) students demonstrated better understanding across all the five difficult areas compared to the comparison class (NTA) students. The findings indicate that female students benefited (a little) more from the intervention than male students. The results show that the C&TA intervention had an effect of the same magnitude across the ability range. Further findings show that C&TA support teaching large classes and that it is possible for a teacher in Uganda to teach in a more interactive/ dialogic way with relatively little training on the communicative approaches. Evidence shows that aspects of the C&TA teaching sequence that were effective in supporting students‘ learning of chemical rate of reaction were: computer simulations and modelling, teaching goals, worksheets, social constructivist perspective on teaching and learning along with the communicative approaches. Further findings show varied benefits and challenges from using C&TA. The teacher and students perceived C&TA as a good method of teaching and learning. Indicating that the use of a computer and talk approach (C&TA) is a feasible alternative teaching approach to didactic teaching in science classrooms in Uganda. It also suggests that C&TA could be adopted for teaching and learning other subjects.