contents Make Your Own
Geometric Space Forms!
These are geometric space forms called "polyhedra," and we're going to show you how to make them. Each one is made of triangles, and each triangle is called a "face." The one on top is a "tetrahedron." It has four faces. Underneath it is an "octahedron," which has eight faces (four above and four below). Below that is a "decahedron." It is hard to tell from this picture, but it has ten faces: five above and five below. (If you could see it from above, it would look like a pentagon.) To the left is a "hexahedron" with six faces. And the biggest one at the bottom is an "icosahedron" with 20 faces. (Do you notice how it almost looks like a pentagon from the side? It looks that way from the top, too.)
Since this is a "real life" project, we turned to the only "real" cat we know, Fatso, to help us. We said, "Fatso, are you sleeping in that baby stroller again? We need you to show some kids how to make polyhedra with just a compass, a straight edge, paper, scissors, and glue. We wish we could do it, but we're just cyber cats. We don't have real paws or anything. So would you help us?"

... But you can see what Fatso had to say about that. Too bad! He's old enough (7 years) and big enough (11 pounds), but he's just plain lazy.

So we asked Emily, who lives in the same house with Fatso. Emily made her very own tetrahedron after watching one big person do it. She is only six (younger than Fatso!), but she knows how to be careful with the sharp point on a compass.

Here is what you will need:
* a compass
* a straight edge (like a ruler, or even the edge of a book!)
* paper (stiff paper makes a stronger space form)
* scissors
* glue, paste, or rubber cement
* thread or yarn and paper clips (if you want to hang them)

Helpful Hints Before We Get Started:

* To make perfect circles with a compass, place the point on the paper, hold the compass steady so that it doesn't change size, and then spin the paper.

* For each polyhedron, be sure that all the circles you draw are the same size.

Ready to get started? Make the tetrahedron first.

tetrahedron hexahedron octahedron decahedron icosahedron

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