Comments about Arbor Scientific Jacketed PMMA Fiber Optic Cable:

In a darkened room, pass one end of a long length (5-10 m) of fiber optic cable through the crowd to the back. Purposely add a few loose knots to the cable and allow it to droop and sag. At your end, place the other end of the cable onto a laser. Have the person holding the far end turn it in various directions toward the group to show the bright light. The light seems to have taken a non-linear path! {It's best to preface this with a demonstration of the laser light's path in clear, large-diameter (~1 cm) plastic, demonstrating total internal reflection paths.} Ask: Is the light coming out the far end still a laser? [Ans: No. It's still monochromatic--but not likely still coherent.]