(To search from previous posts on this topic, use the Search box on the right.) I suspect that by far the most common introduction to geometric construction in US classrooms is a presentation by the teacher (or textbook) on various compass and straightedge construction techniques. “This is how you construct a perpendicular bisector. This is… Continue reading More on Geometric Construction
If you’ve been reading my blog for a while, you know that I’m a big fan of geometric construction. I have written about it here more than once, and my Web site includes quite a bit of curriculum involving construction. See the end of the post for additional links. I have many reasons for this… Continue reading Geometric Construction for Middle School
Readers of this blog probably realize that I’m very much into geometric construction. This is in part related to my general interest in puzzles, in and out of the classroom. (In my other life, I construct cryptic crosswords.) My first math education publications were books of geometric puzzles for grades K-10. My pentomino puzzle books stayed… Continue reading Geometric Construction, continued
In the days preceding a recent lunar eclipse, my daughter saw an illustration that seemed to show that the Moon’s diameter was just about equal to the width of the penumbra. She conjectured that if that were true, it may be because of the fact that the apparent diameter of the Moon (as seen from… Continue reading Astronomy and Geometric Construction
“Proofs Without Words” are proofs based on a visual representation of a theorem which provides a convincing argument about its validity without the need for any accompanying text. The genre has been much enriched by the increased availability of computer animation. This is of course relevant to math education: many of the concepts we teach can be illustrated visually, including with… Continue reading Seeing is Believing?
I taught geometry for decades, starting in the 1980’s, and loved it. I’m reasonably good at manipulating algebraic symbols, but I don’t especially enjoy it. In contrast, I am happy to spend plenty of time on visual puzzles, and I am enthusiastic about sharing that passion with colleagues and with students. Early in my high… Continue reading Transformational Geometry for Teachers
As my retirement starts to kick in, I no longer attend conferences — except for one: the annual meeting of the California Math Council (Northern Section.) Once again, I had a great day at Asilomar, a beautiful spot near Monterey, right on the Pacific Ocean. Here is my annual report. Conic Sections Figuring out an approach to… Continue reading Asilomar Report: Conic Sections
When I was much younger, I was under the impression that anything students “discover”, they will remember. Over time, I realized that this is not really true. First of all, what I hope they discovered may not be what they actually understand. But also, it’s not clear to them what is important about their discovery,… Continue reading Towards Inquiry
In addition to my blog on WordPress (this site) I maintain a huge math education site, featuring articles about teaching math and tons of curricular materials. You should definitely check it out. I keep track of updates to the site on this page. I added an applet about the graph of y = ax2+bx+c :… Continue reading Math Ed Page Updates
4 December 2021: I presented a hands-on workshop at the California Math Council conference in Asilomar — Tiling: a Springboard for Geometry. Tiling the plane (tessellation) provides opportunities for students to do creative work they take pride in. It connects with art (e.g. Escher) and culture (e.g. Islamic design). And it provides a rich context… Continue reading News
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