16 foot tall tensegrity ball

Here is the introduction to my latest instructable, which was featured on instructables.com.

I made this giant tensegrity for GeoBurst at the Vancouver Island Mini MakerFaire 2012.

GeoBurst creates ZEST for MATHEMATICS by doing hands-on mathematical activities with kids. Check out our website and see what this emerging not-for-profit is up to!

I believe in the intrinsic value of mathematics, and most especially geometry and symmetry. Learning to appreciate math for what it is will reduce our aversion to it when we actually need to use some.

Learning objective: Students will learn about two of the 5 platonic solids, the icosahedron and the dodecahedron. They are both visible in this structure because their dual relationship is highlighted here. The tensegrity ball is neither the icosahedron nor the dodecahedron, yet it is also both. Students will also learn about the principle of tensegrity, and this activity can be partnered with the building of a smaller tensegrity such as the ones on GeoBurst. Students will also learn about knots.

Learning Keywords: 3D geometry, Icosahedron, dodecahedron, platonic solids, dual solids, tensegrity, symmetry (and symmetry groups), triangles, pentagons, engineering, structures, building materials, knots… etc :)

A little background: I first built a small model last year after seeing George Hart’s post on Make. I also had these 1/2-1 inch diameter 8-foot bamboo poles, lying around for a project like this, but the giant tensegrity ball idea went into limbo because I didn’t know how to reliably attach the ropes to the ends of the poles. You can’t just notch bamboo, because it will split to pieces, and I didn’t want to buy fastenersfor 60 ends of poles.

The answer lay in knots, and this is what my instructable is about. Good, non-slipping, easy and fast knots. Tying the knots for this project took nearly 35 man hours, for which I had help from three friends. Veronika Irvine, Eric Davies, and Charles Campbell. The rest of the time was spent rolling the ball around at the park!