Planar graphs via squashing polyhedra and dynamic geometry

Extract

Planarity is a concept that appears in most discrete mathematics courses (in particular, it is a syllabus item in all A level Discrete mathematics syllabuses). I have recently taught a unit in graph theory to a group of BEd students and, when I came to the concept of planarity, I decide to approach it in a different way – through the context of Cabri Géomètre, a dynamic geometry package. In the article I would like to share some of my ideas and reflections on this approach to teaching this topic, paying particular attention to the role of Cabri Géomètre in scaffolding the important ideas involved in an understanding of planarity.