The Hoberman Sphere never ceases to amaze. The large version expands from 9" to 30" in diameter; the smaller version from 4” to 12.”
A booklet about the geometry of the Sphere and activity sheets comes with it.
Each sphere includes a pulley, hardware and instructions, so if you ever get bored playing with it, you can hang it as a cool, kinetic mobile.
The instructions recommend 4 and up. We have sold it to younger children (though not babies). Many of our customers buy them for their grandkids, but keep them at their own homes ;).
The original Hoberman Sphere was installed in 1992 as the central exhibit in the Liberty Science Center's atrium. The sphere was re-installed in 2007 in the newly renovated museum's entry hall. Suspended by cables, the 700-pound aluminum sphere expands and contracts smoothly and continuously. http://www.youtube.com/watch?v=xRL0tMaNgjQ
The designer, Chuck Hoberman, is part artist, part inventor, and part architect. He does truly amazing things with unfolding structures. In 2010, the Hoberman Sphere was added to the Museum of Modern Art's permanent collection
Lots of cool examples of his many spheres are available online.