Chemical bonding in Swedish upper secondary school education: a force-based teaching model for enhanced understanding

This study investigates if a force-based teaching approach, based on quantum mechanical principles and developed in a lesson study, would enhance the understanding of chemical bonding among upper secondary school students. The teaching approach was based on research on the teaching and learning of chemical bonding. The study included first-year students in upper secondary school in a pretest–intervention–posttest design. During four lessons the students were introduced to the underlying forces leading to the formation of all chemical bonds, specifically focusing on ionic- and covalent bonds. The first lesson, which included a presentation of coulombic interaction as a common basis of bond formation, was developed and improved through a lesson study. The lesson was revised based on feedback from 75 students describing why chemical bondings occur. After the four-lesson series about chemical bonding, a total of 67 of the 75 enrolled students had completed both a pre- and a posttest. The students’ answers to the tests were analyzed based on Bernstein's theory of vertical hierarchical and vertical horizontal discourse. The results of the posttests show that 60% of the students demonstrated solely or predominantly vertical hierarchical knowledge structure. These results indicate that most of the students could understand the force-based approach of chemical bonding by using a general theory, spanning over a wide range of the natural science field, with an abstract and specialized language. Moreover, the students who internalized a hierarchichal knowledge discourse about chemical bonding earned higher final grades in the upper secondary school chemistry when compared to students using a horizontal knowledge discourse, indicating that a force-based approach might facilitate a deeper understanding of other subareas within chemistry. In chemistry education research, the effect of using a force-based approach to teach chemical bonding has not previously been widely tested among upper secondary school students. This study responds to the need to test alternative teaching models to facilitate students’ understanding of chemical bonding.