Active teaching of diffusion through history of science, computer animation and role playing

We developed and tested a lesson plan for active teaching of diffusion in secondary schools (grades 10–13), which stimulates understanding of the thermal (Brownian) motion of particles as the principle underlying diffusion. During the lesson, students actively explore the Brownian motion through microscope observations of irregularly moving small particles, a computer animation showing events at the molecular level and a role play simulating diffusion. The lesson plan follows the history of scientific discoveries, from Robert Brown's description of particle motion to Albert Einstein's explanation of the phenomenon at the molecular level. Students are encouraged to learn towards conceptual change and to critically evaluate scientific models. Both secondary school teachers and students perceived the lesson as interesting and easy to understand. The lesson plan was developed through a universityschool partnership project.