A group of six balloons are tied together to form an octahedron. The balloons are popped one at a time to form the bipyrimidal and the tetrahedral shapes.
- Six 9-12 inch balloons of different colors
- Push pin in a cork stopper
Blow up the balloons to mid size and tie them together to form an octahedral shape. Pop the balloons to get the various shapes.
Hint: Oddly, balloon phobias are common. You may want to warn your students that you’ll be popping the balloons. Also, the demo works better when the balloons are not over inflated.