Section 5 : Cells
Theme: Dealing with challenging ideas in science
By the end of this section, you will have:
- used pair discussion and probing questions to review and develop students’ understanding of the basic structure of plant and animal cells;
- used mathematical activities that help students gain an idea of the relative size of cells;
- helped students make and evaluate their own models of cells.
Your students will have been taught about cells in primary school. However, they are likely to have a number of misconceptions about what cells are really like. Developing an understanding of the size of cells is difficult. The fact that cells can only be seen with the aid of a microscope adds to this difficulty. Research has shown that some students confuse ideas about cells and molecules, including their relative sizes. Although three-dimensional diagrams of cells may be shown in textbooks, photographs of cells as seen under the microscope are always two dimensional. It is difficult for students to imagine the 3D structure. Other common incorrect ideas that students may hold about cells include thinking that plant cells are surrounded by cell walls instead of cell membranes, rather than by both a membrane and a wall.