The use of structured problem-solving strategies to improve the teaching and learning of Chemistry

Abstract

The study aimed to investigate effect of structured problem -solving instructional strategies on Advanced Level chemistry learners’ achievement in stoichiometry and ionic equilibria. The population of the study consisted of Advanced Level Chemistry learners from 15 high schools in Gweru urban District of the Midlands province in Zimbabwe. Using convenience sampling techniques 8 high schools with n=525 Advanced level Chemistry learners and 8 teachers participated in the study. Four schools formed the experimental group (n=250) and the other four school formed the control group (n=275). The study employed a quasi-experimental design with a non-equivalent control group approach consisting of pre-and post-test measures. Intact classes participated in the study as it was not possible to randomly select participants for the study. The qualitative part of the study involved conducting semi structured interviews with teachers, focus group discussions with learners as well as classroom observations. The quantitative data were collected using standardized achievement tests in stoichiometry and ionic equilibria. The problem-solving instruction was implemented in four experimental schools by the respective chemistry teachers who had been trained as research assistants on the use of the problem-solving strategies in chemistry teaching. The four control schools were also taught by their teachers using the conventional lecture method. The constructivist theory framed the study. Analysis of Covariance (ANCOVA) was used to analyze data. The results of this study indicated that the participants in experimental schools performed significantly better than participants in control schools on certain aspects of problem solving performance. Furthermore semi-structured interviews, focus group discussions and classroom observations revealed that participants rated problem-solving instruction highly as an effective teaching strategy to enhance the problem solving skills of learners in A’ level chemistry. The Scheffe’s post hoc test indicated that students taught using the Ashmore et al problem-solving instructional strategy performed better than those taught with the Selvaratnam-Fraser problem-solving strategy. The study also revealed that student had difficulties with the mole concept, Avogadro’s number, limiting reagents as well as determining theoretical and percentage yields. Students were also found to have difficulties with acid-base theory, buffer solutions, and application of Le Chatelier’s principle in solving buffer equilibria problems and solubility equilibria. Furthermore the study revealed that students rely on algorithmic strategies when solving stoichiometry and ionic equilibria problems and do not demonstrate adequate understanding of the concepts involved. It is therefore strongly recommended that chemistry teachers use problem-solving instructional strategies in their classes to facilitate students’ problem solving performance. In addition pre-service chemistry teachers should be properly trained in instruction that promotes problem solving and how to implement effective problem-solving instruction. Furthermore, in-service training for practicing chemistry teachers is recommended so that they can embrace the skills of the problem-solving strategies for effective implementation of the strategies in teaching chemistry.