Fiber optics project, need suggestions

We are asked this year, to do a project for Expo-Science prior to our Physics class.
So me and a friend, who's dad works at Nortel and can easily score us fiber optic material which supposedly is related to Physics when it comes to Optics, want to build something which isn't TOO hard but also has to be very interesting.
We believe Fiber Optics is the way to go, but I have no clue what kind of things can we show in front of a big crowd in the school agora, and explain to them!

Any thoughts, links to some prototypes we can try basing our project on? Let it be interesting, and it must have good Physics relationship because we want to demonstrate how Physics affect that item's working.

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Where did your THGC username come from and why did you choose it? <A HREF="http://forumz.tomshardware.com/community/modules.php?name=Forums&file=viewtopic&p=19957#19957" target="_new">Tell here!</A><P ID="edit"><FONT SIZE=-1><EM>Edited by Eden on 09/19/02 09:30 PM.</EM></FONT></P>

Ahem, that would technically be dangerous in an open public place, no?!
Don't wanna fry out too many people!

Also, you sure that coil electricity is Physics? I would say it is more Electricity oriented.
Our project can have Chemistry, Biology into it, but must be Physics based. So you can talk about the Eye and reflection for example, eye being described using Biology, and the reflection being Physics oriented.

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I'm pretty good with physics. Electricity is about as physics as you can get. And a tesla coil isn't what Red Alert made it out to be. Tesla was able to transmit electrical energy over great distances without wires via special coils. Unfortuneatly, we don't know how he did it, and he's not around anymore to tell us.

Fibre optics is pretty cool stuff. You could show how you can bend light around a corner via the fibre cables, and explain what total internal reflection is. Basically how the cables work is this:

You know how when you look into a pond, and you want to poke something at the bottom with a stick, how it never seems to be where it should, and how it looks as though the stick bends at the point where it enters the water? That's because of the difference in optical densities between the air and the water. The light bends as it goes from the water to the air. The degree of the bending depends on the angle at which the light is crossing that threshold (a straight on entrance produces no bending, while a flatter angle produces more of a bending effect).

There is an angle called the critical angle where the light actually is bent so far it is entirely reflected back into the first medium (eg, the water). This effect is called total internal reflection.

The same happens with glass (ie: fibre optic cable). There is a light that shines on the end of the cable at such an angle that the light beam is reflected back into the glass perfectly. Thus, the light is confined to the glass, and must travel down the cable until it reaches the other end.

You can do a simple demonstration with a prism to show the bending effect, and set up a few equations showing how everything works, then wow them all with the fibre optic cable stuff.

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