## A Geometry Shop Class (Labor Day weekend, 1998)

#### PROJECT:

Concentric hierarchy shapes for classroom demonstrations

#### PROCESS:

Used compass and ruler to define 4" prime vector for tetrahedron, cube etc. Elmers & glue gun to hold edges, cloth tape applied when dry.

Because of the thickness of the bookbinder material (28 ply), Russ incorporated thickness into dimensions of cube faces, so the gluing of adjacent sides might be flush, making for a stronger box with an internal volume having face-diagonals of 4". Other shapes took beads of hot glue along the creases (no attempt to bevel or mitre edges), followed with a tape covering.

We use red lentils (actually orange -- goes well with black tape) for pouring from one shape to another, to demonstrate volumetric relationships (one face left "open" on each shape). Working on pouring technique (might need a funnel).

We decided the rhombic triacontahedron was too precise and complicated to get out of the thick 28-ply so returned to Art Media on First Day for some thinner paperboard (also picked up more roles of cloth tape).

Helps to slightly bend 28-ply stuff apart with each stroke of the Xacto blade. We used a large paper cutter at Kinko's (protected slider cut, not one of those old cleaver-style models, which have been fazed out for safety reasons) to do long strips for the rhombic triaconta, leaving only slant-cuts for the Xacto:

```------------------------------------------------  <-- Kinko's
/    /    /    /    /    /    /    /    /    /   }
/    /    /    /    /    /    /    /    /    /    }
------------------------------------------------  <-- Kinko's
```

Shapes made (over Labor Day weekend):

```                          Volume
Tetrahedron                 1
Cube                        3
Octahedron                  4
Rhombic Triacontahedron     5*
Rhombic Dodecahedron        6
Icosahedron                18.51+
Cuboctahedron              20

* given upper limits on precision associated with these construction
methods, there's no easy way to differentiate the E-module from the
T-module RT, so we'll say this is the T-mod one, with volume 5
precisely.  We might be off by a lentil or two.
```
I have presentations shaping up in Philadelphia, DC and New York in early November but haven't decided if I want to try lugging these shapes in my hand-carry or checked. I am hopeful that local centers will by then have similar props on hand for public domain sharing.

Kirby
Oregon Curriculum Network

```SUPPLIES*

Office Depot
-----------------------
Glue Gun     \$5.79
Knife.Xacto  \$2.49 x 2
3M Tape      \$1.49 x 2
Glue All       .48
Stanley Glue \$2.69
Compass      \$4.59
Ruler.Metal  \$3.99
Ruler.Metal  \$2.99
=====
\$33.28

Art Media
-----------------------
28 Ply Recycled 32x40    \$4.50
Rotex 3/4" Tape (black)  \$1.39
=====
\$5.89

Fred Meyer
-----------------------
Red lentils              \$3.83

* not counting rhombic triaconta paper, didn't use the 3M tape,
had to get 3 more roles of the black stuff.
```