Here’s a quick & easy one: We have an assortment of lasers lying around the house. 3 wavelengths (colors) that have become cheap in recent years are red, green, & ultraviolet (purple). Purple is especially handy for an assortment of uses- one of them being that it will energize phosphorescent materials like crazy. It’s a good idea to use some filtering glasses when using UV especially concentrated in the form of a laser. We didn’t in this clip, but we’re pretty conscientious about it in general- fortunately Delilah’s very good about following the rules with this stuff. Your mileage may vary.
Anyway, so in a nutshell, we tie a thread to a rigid axle attached to this pocket laser. Along that axle are two threaded parts: A steel ballast that can be adjusted along the length to change the center of gravity. The next part is just a little threaded plastic hanger. That’s what we attach our thread to.
In this iteration we cut two plastic rings from standard PVC tube. After you cut them into rings you can put a vertical cut perpendicular to their axis. That will make them into a C shape that can be used to physically connect the weighted part to the laser, and also to hold down the “on” button of said laser. Then you can just adjust all 3 variables (connection point to the axle, ballast point, and connection point along the laser) and observe the effect on different patterns. Obviously spin and bounce play the largest roles in the end result.
The glow sheet I used I just happen to have lying around, but you can get a similar result by painting some glow paint onto a cardboard sheet.