Education Blog

Building polyhedra to teach geometry to middle school students


If you’re a middle school math teacher and want some tips on how to develop your students’ spacial sense by identifying, describing and constructing regular polyhedra, then visit Geometry:  Let's Face It, a professional development video lesson with support materials available for free in the basic version of PBS LearningMedia.

Though the video was made in 1994 when on-demand educational videos and professional development meant turning on the VCR and popping in a VHS cassette, the content is “excellent,” according to Jayadev Athreya, assistant professor and director of the Illinois Geometry Lab at the University of Illinois.

The video was made during a lesson in a real classroom (early reality TV!).  We see Barbara Urell, a middle school teacher from Oxford, Ohio, introduce her students to three-dimensional figures by reviewing polygons and regular tessellations. Students construct five regular polyhedral with straws and record the number of faces, edges and vertices for each.  At the end of the 27-minute video we see the students looking for the relationship between the number of faces, edges and vertices.  They are asked to figure out a pattern and prove or disprove it in front of the class. Ultimately, they discover Euler's formula.

There are points in the video where we hear a voice-over of Ms. Urell assessing her teaching and thinking as she develops each part of her lesson.  For example, by starting class with a math answer and asking her students to come up with the answer, she’s hoping to teach them divergent thinking.   She has students work in groups to teach them how to talk to each other without putting anyone down.  Straws are used to build the polyhedra and help students explore 3-D figures: “You can’t use paper to do that,” she explains.  One lesson learned: devote more time for students to relate polyhedra shapes to the real world.

What’s in the collection?

There are four videos in the collection: one 27-minute video (as described above) and three excerpts under two minutes each. The collection also contains a written geometry lesson plan and professional development discussion topics.  The Common Core State Standards met by the lesson are listed as well.

If you like what you saw in Geometry:  Let’s Face It, you might be interested in the other 11 (as of the writing of this post) professional development videos for middle school geometry teachers available for free in the basic version of PBS LearningMedia.