Ninth grade students' understanding of diffusion and osmosis after participation in direct or inquiry-based lessons : a mixed methods study.


Access rights

Worldwide access
Access changed 12/4/17

Journal Title

Journal ISSN

Volume Title



In this embedded mixed methods case study, quantitative and qualitative data were collected to assess the impact of direct and inquiry instruction on students' understanding of diffusion and osmosis. Participants of this study were 44 ninth grade students from an inner city charter school in Central Texas. Twenty-three of these students participated in direct instruction lessons on diffusion and osmosis; 21 participated in inquiry-based lessons on diffusion and osmosis. The quantitative phase, which was conducted first, addressed students' understanding of diffusion and osmosis after participation in either direct or inquiry-based instruction. Two different instruments were used to gather quantitative data: a diffusion Concept Evaluation Statement (CES) and the Diffusion and Osmosis Diagnostic Test (DODT). The CES describes a science-related scenario and asks students to provide an explanation of the phenomenon described in the statement. The DODT consists of 12 two-tier multiple choice items. For the CES data, more students in the inquiry group achieved a sound or partial level of understanding than did students in the direct group. Both groups experienced small, although significant, improvement in their overall DODT scores, and the difference between groups was not significant. A closer analysis of individual DODT items revealed differences in the types of common misconceptions expressed by each group. The purpose of the qualitative phase was to provide insight into the quantitative results. Written surveys and focus group interviews were conducted to examine various factors of direct and inquiry-based instruction that influenced students' understanding of diffusion and osmosis and performance on the CES and DODT. Students in both groups found laboratory and hands-on activities to be beneficial in improving their understanding of diffusion and osmosis. Students in the direct group also liked the use of foldables and clicker questions and reported that the repetitive nature of direct instruction helped them to understand diffusion and osmosis. Students from the inquiry group benefited from group work and discussions and reported that inquiry-based instruction required them to think about the information in a different way because they had to make sense of their observations on their own, rather than being explicitly told the new information.



Science education. Inquiry. Inquiry-based instruction. Direct instruction. Diffusion. Osmosis.