Future science teachers' understandings of diffusion and osmosis concepts

The concepts of diffusion and osmosis cross the disciplinary boundaries of physics, chemistry and biology. They are important for understanding how biological systems function. Since future (pre-service) science teachers in Slovenia encounter both concepts at physics, chemistry and biology courses during their studies, we assessed the first-, second- and third-year science teachers' understanding of diffusion and osmosis using a diffusion and osmosis diagnostic test. We found that the knowledge of first-year pre-service science teachers about diffusion and osmosis was largely superficial. Second-and third-year students achieved better test scores; however, not as high as we had anticipated. We also found that the pre-service teachers who had actively approached the concepts (e.g. conducted experiments) of diffusion and osmosis in upper secondary school achieved significantly higher test scores.