Here is my lesson on why the sky is blue. It's a combination "springboard"/presentation. That means students get a sheet with questions to be answered through class discussion during the presentation. The presentation includes images and animations to illustrate what's going on. Read over the student worksheet (and especially the teacher's edition with answers) and step through the interactive presentation before trying this one in class. This is no autopilot-style lesson. The teacher must teach this one and you need to know some details to flesh the whole thing out.
Student Springboard (worksheet)
Teacher's Edition (answer key)
Presentation (zipped interactive QuickTime: 39MB)
Means to project the presentation (not free)
Resonant tuning forks
PTSOS visible optics "skinny fish" tank
Scattering agent (Mop-N-Glo or equivalent)
Flashlight (mini maglite or equivalent)
As always, I'm eager to hear your comments.