The Hoberman Sphere: An All-Purpose Prop

Participants at the recent Wendy's International Trainers' Conference wanted more information about "the shrinking and expanding sphere". Actually, I borrowed that sphere from Raja Thiagarajan. Here is his own explanation of the Hoberman Sphere. -- Thiagi

ISPI 1998 -- 99 Seconds Presentation

The Hoberman Sphere: An All-Purpose Prop

Raja Thiagarajan, Workshops by Thiagi, Inc.

Technical Info

The Hoberman Sphere was invented by Chuck Hoberman, an inventor with degrees in art and mechanical engineering. It isn't really a sphere: Technically, it's a icosadodecahedron, which means that it is a geometric solid consisting of 20 triangles and 12 pentagons. Or you can look at is as a collection of six great circles, approximated by polygons.

The Hoberman sphere expands and contracts with its hubs moving in straight lines radiating from the center. Each point of intersection reinforces the structure. If you fully expand the sphere and rest it on a pentagonal face, it will hold its shape. If you turn it slightly so that it's resting on a hub, it will quickly close.

The largest Hoberman sphere in existence is in the atrium of the Liberty Science Center in Jersey City, NJ. It is 18 feet in diameter (when fully expanded), made of aluminum and stainless steel, and weighs 700 pounds.

Using the Hoberman Sphere

You can use the Hoberman sphere as a dynamic analogy for many things. Here are some examples:

Begin with the closed sphere and explain that this is the scope of Instructional Technology. Expand the sphere and explain that this is the scope of Human Performance Technology.
Show the closed sphere and explain that this is the classical view of intelligence. Expand the sphere and announce this is Howard Gardner's view of multiple intelligences.
Show the expanded sphere and explain that this is the audience's current understanding of the use of the sphere. Close the sphere and explain that this is what will happen to their memory of the device unless they come up with personally meaningful application examples.
Show the expanded sphere and explain that this is the time consumed by a lecture. Now close it and explain this is what happens during a 99-seconds presentation.

Availability

The Hoberman sphere is available from many sources. We recommend The Discian Group. They have a nice a Hoberman sphere page, including ordering information.