Introduction
2-liter soda bottles turned water rockets are as shrieking good a time as a water park and a lot easier to build. They streak into the air faster than the eye can track while dousing everyone in the launch area with water. Occasionally, my middle school students host and teach classes of elementary school kids from across the street to make a take-home science project, and we always finish off with a couple of launches. Years later, when I teach those now-middle school kids, they never remember me, but invariably remember the water rockets! I have been searching for the "perfect" water rocket for two decades. I finally have a design that I'm happy with: it's easy to make with locally available materials, dirt cheap, and it launches safely overhead. Of course, 2-liter bottles are free, and the launcher is virtually indestructible--no "O" rings or anything to wear out. A bicycle air pump provides the air pressure. I am confident that a normally handy person can make this project in an hour or two. I have created step by step instructions for making a water rocket launcher. It's free--I do ask that you give me feedback about things like clarity of the directions and I ask that people outside North America inform me about the availability of the pipe sizes in their respective countries using metric measurement. It is a great joy when experimenters share design innovations and improvements that I can in turn share with everyone through this site. Feel free to link to sciencetoymaker.org or any page of it so others can access the material directly (there are many other science projects)
A frank discussion of the safety issues involved with water rockets.
See the links to the best water rocket web sites I've found--including slow-motion launches, aerial photography and multi-stage rockets