Acrylic Light Pipe

PIRA 6A44.40

The acrylic light pipe shown at right works well to illustrate internal reflection and how a fiber optic cable works.  Shine a laser at one end of the rod, and laser light will be visible coming out the other end.  The index of refraction of the acrylic can be estimated by changing the angle of the incident beam until the critical angle is reached for the first internal reflection.