This is a great way for students to visualize intersecting planes in 3-D space.
It also very hands-on and does not require a lot of time.
6 sheets of paper (3 different colors x 2 sheets each)
I buy colorful reams of paper and take them to Kinkos (a copy shop) and have them cut off one end of each ream.
Turn the 8.5" x 11" paper into 8.5 "x 8.5" squares.
They usually charge a dollar or two per ream.
You could also do this yourself if you have a big paper cutter. It just takes longer since you have to cut 4-10 sheets at a time.
I usually pair up my students. It makes the folding go quicker and it is much easier to put together if you have 4 hands working and holding pieces.
My students are good at seeing Points and Lines and intersections in 2D. But when I introduce Planes in 3D space, they have a hard time visualizing it in their head. So I do this activity to give them a physical object that represents Intersecting Planes in 3D space. It is important to have the 3 colors, as these represent the 3 different planes. This is not a perfect example, but the kids really seem to get into it and they have a much better grasp on 3D space.
You could also extend this later to include Concave Polyhedrons.
Folding the Paper
I did not create this lesson. I was taught it in a training seminar. I do not remember the presenter or even the name of the seminar. It was shared freely with me, and you should share it with others :-)
Step 1: Folding the Paper
1) Fold the square in half each direction
2) Flip the paper over
3) Fold the square in half diagonally each direction
4) Form a pyramid with the paper
5) Repeat steps #1-4 for each square
Why this process:
There are simpler ways to fold the paper to get all the creases you need. But, I fold them this way to make the paper naturally form the pyramid.
A common error of my students it to make a Diamond instead of the Pyramid. To fix this, just flip the Diamond inside-out.