The “Julia Child” of kids’ hands-on science
Test the idea yourself: Put a holiday light on one rim of a heavy glass measuring cup or dish. See where the light emerges on the rim on the opposite side. Move the light back and forth and watch what happens on the other side. The light travels down the side, and bends to go across the bottom and up the other side, but if you look at the cup sideways you can’t see the beam. Light stays inside the glass as it travels from rim to rim.
Could we make something like a wire from glass that can transmit light? Absolutely! An optical fiber is a flexible, transparent fiber made of glass or plastic that acts as a wire for light. Imagine a beam of light entering a fiber at exactly the right angle to bounce off the inside wall of the fiber where it meets the air. It is then reflected at exactly the same angle to bounce off the opposite wall making a zig-zag path until it reaches the end of the fiber. This internally reflected light stays inside the glass fiber as it travels at the speed of light.
HUGE quantities of all kinds of information—words, pictures, music, and videos—can now be sent through optical fibers, much more than through wires. A modern network with copper wiring can handle about 3,000 telephone calls at the same time, while a similar system using fiber optics can carry more than 30,000!
So when you hit “send,” know that your holiday message is a blinking beam of light, bouncing off the inside walls of a glass fiber on its speedy journey to friends and family. How ‘bout that!
Want to know more about optics? Have a look at Vicki Cobb's book Light Action! She co-authored it with her son, Josh, who is an optical engineer and her other son, Theo, drew the pictures. It's full of experiments that let you use optics to
Best wishes for the holiday season from the Nonfiction Minute authors. We are going to be joining all of you teachers and students for a holiday break. Even though we won't be posting during the holiday, we will still be thinking of interesting things to write about in 2015. Watch for us to resume on January 5 with a Minute on how January 1 got to be the start of the new year.