You can also show how IR being part of the Electromagnetic spectrum will undergo Total Internal Reflection.
The LED holder I used came from the mindsets Sep Sample Pack Waves And Radiation
It is worth purchasing the kit, however I have emailed mindsets to enquire about just purchasing the holders.
Then you need some optical fibre
I cut a length then glued it into the holder using epoxy resin.
I had one with a red LED in to show you all TIR in the optical
Then make the same thing with an IR LED and use your modified camera to show TIR.
I also like the way you can show how the thick plastic is transparent to the IR from the LED. Look at the holder in the video above, you can see all the IR passing straight through it.