Projectile Motion Sprinkler
The Projectile Motion Sprinkler is a great way of simultaneously shooting streams of water with the same velocity but at different angles. The Sprinkler shoots streams at 20, 30, 45, 60, and 70 degree angles. Note that the 45 degree stream goes the farthest. More importantly, notice that the 20 & 70 and 30 & 60 streams hit at the same spot (try doing that with a garden hose!)
Originally, I built a PVC version (see attached .doc for details), but most people do not have access to tools necessary to build one accurately.
The 3D printed version is about 7" long and was printed vertically. At medium speed and 35% fill it took about 8 Hrs. I used PLA, but I'm sure any type of filament would work fine. I designed it in inches but my printer is in millimeters, so make sure to check the scale before printing.
After printing, affix a 3/4" PVC male adapter to the end using some silicone sealant (don't worry about small leaks if using outside). Mount on a piece of wood for stability. Then attach a standard washer hose to it and connect to outside hose bib. Vary the water pressure to get the desired effect.
Video of original PVC version in action.
Photo of 3D printed version in action.