Physics Central
Physics Central: Physics in the Living Room: Remote Control Tricks
An easy experiment through which students learn about light rays and the electromagnetic spectrum. Requires a TV, its remote, and a hand-held, flat mirror.
University of Wisconsin
The Why Files: Infra Red Eye Special
A description of the ways in which infra-red is used in astronomy, including an extended example describing how infra-red was used to learn about Pluto's moon, Charon. There are also links to other sites of astronomical interest.