A zipper Möbius strip from Mathjams

Saw this tweet yesterday:

A few weeks ago we’d done another Möbius strip-related project I saw in one of James Tanton’s books:

An absolutely mind-blowing project from James Tanton

After seeing the re-tweet from Mathjams I thought it would be fun to try this project, too. I ran to Joann Fabrics and found some 48 inch zippers and my wife helped me figure out how to make the shape. She did the sewing and commented that she was surprised that the pins we had holding the shape together started on once side and ended up on the other side! So, there’s a neat “what do you notice” math and sewing project here, too. See also:

How to sew like a mathematician by Evelyn Lamb

I had each kid go talk about the shape separately so that the other kid’s ideas wouldn’t spoil theirs. Here’s what my younger son had to say as he played with the shape:

and here’s what my older son had to say:

I love this shape and exploring it is a great math project for kids (and probably for everyone!). Thanks to Mathsjam and to Andrew Taylor for sharing it.