Question: Hello Duncan! How do fibre optics work and are there lots of reasons they can be used for?

Duncan McNicholl answered on 4 Nov 2017:

Go find a window.

I’m serious: go now, and find a window. Have a look at it, and have a look at you in it. Can you see that there are two overlapping reflections? The reason for that is that the light that’s bounced off of you is bouncing off the front of the window *and* the back of the window.

A fibre optic works by shining light into a glass tube in a way that it keeps bouncing off the inside of the glass, the way the light bounced off the back of the window that you looked at. You did go and look at a window, didn’t you? If you didn’t, you really should. The great thing about science is that you never have to just trust anything that someone says to you: you can go and check it out yourself.

So fibre optics keep the light inside themselves because of all the reflections, and that means that you can get light from one end to the other even if you bend it or wind it up or unwind it, and that means that we can keep one end near and put the other wherever we want and get light from here to there. Mostly we put the two ends really far apart and flash lights along them to move data for the internet ( that’s why you can email people in america, there’s a fibre under the ocean), but I’m using them because we can also put one end inside you and shine light through it to have a look at your insides if you don’t feel well. We can also use them to look inside car engines, or anyhere that we wouldn’t be able to see normally.

I hope my answer wasn’t too long.