Introduction

Six balloons tied together in a bunch arrange themselves in an octahedral fashion.  As balloons are popped the resulting number conforms to the molecular shapes of VSEPR theory.

To Conduct Demonstration

  1. Show six balloons in octahedral arrangement.  Pull tightly on the slack end of the string to enhance the shape.
  2. Pop one balloons.  Show how the five now conform to trigonal bipyramidal shape.
  3. Continue popping balloons one at a time, showing resulting arrangements (4 is tetrahedral, 3 is trigonal planar, 2 is linear).

Note: Do not pull short end of string through the glass tube after balloons are popped!