Alternative Conceptions of Diffusion and Osmosis

Uncovering Alternative Conceptions of Diffusion and Osmosis Through Lesson Study

Through lesson study, a research lesson on diffusion and osmosis was developed collaboratively among four Biology teachers of a partner high school in Metro Manila and four NISMED researchers.  The group developed a structured inquiry activity on diffusion and osmosis using existing activity sheets of the partner teachers as references.  Student learning and alternative conceptions were closely observed during the implementation of the lesson.

Through classroom observations, analysis of accomplished activity sheets, and student interviews, it was revealed that students have difficulties in differentiating diffusion from osmosis, and understanding the terms hypertonic, hypotonic, and isotonic.  Students also perceived that there is a directed movement of particles from a higher concentration to a lower concentration.  This suggests their inability to integrate random molecular motion and collisions in explaining the movement of molecules.  Identification of these alternative conceptions is an important prerequisite to developing appropriate lessons and activities.  Appropriate computer animations may be used in conjunction with other instructional strategies to scaffold students’ understanding and visualization of random molecular motion and collisions to better understand diffusion and osmosis.  To improve the research lesson and address the misconceptions identified, the next step would be going through another cycle: revisiting, revising, and implementing the research lesson.

The full text of the study is one of the chapters of the book titled “BOOK 1.  LESSON STUDY: PLANNING TOGETHER, LEARNING TOGETHER” which will be published in print form by UP NISMED this first quarter of 2013.

By Maria Helen Catalan