We've gone through several iterations of an activity called Light Play that lets participants experiment with lights, shadows, reflections and refractions. This spring we created a new system for the activity in the tinkering studio and made new lights and screens to work on the museum floor. I've just finished an instructable showing how to make the components and I wanted to share it here on the blog.
While we wanted to share the specific instructions about how we made the set for the wear and tear of daily use in the exploratorium, the recipe is really just a starting point or an inspiration to make a tool for experimentation that makes sense for your setting.
Marlene, a teacher who attended our January Art of Tinkering Workshop and has been active in the coursera class, posted a great remix of the 'light play set' on our rebel mouse tumblr.
These are made with a cardboard box and mylar film for a cheaper and lighter construction. However they create amazing results and would allow students to play with light and shadows.
I hope that you enjoy the instructions and please let us know if you have any feedback or how you adapt the instructable to suit your needs.