Students measure how light from a source spreads out using graph paper or a perf board.
What makes this hands-on is that students can put in different parameters and see the effect on the screen. At the end students apply what they have learned to visual data from the Hubble. Requires a reasonably modern computer and modem. Basic activity in which students pull adding machine tape marked with wave cycles through a portal and keep track of frequencies. This demonstration for showing why the sky is blue can be converted to an activity where students show the effect of scattering for themselves.