The Sphere of Fear 
Hiding behind every amazing feat is a great application of physics. Many circus performances include something known as the sphere of fear, or circle of doom, or the Globe of Death. The basic design consists of a metal cage in the shape of a sphere that is big enough to allow a motorcycle or two to ride around inside. If the rider goes fast enough they can even ride upside-down or around the side of the sphere without falling. If you are interested in...
