Getting tired of pin the tail on the donkey? Bowling alley booked? Well, we’ve found that newly-minted 5 year olds and friends like nothing more than to spend an hour decorating and launching their own water rockets.

We’ve thrown this party twice now, and it was blast both times.

Make The Rockets

Making the rocket blanks for the little X-Prize hopefuls is pretty easy if somewhat tedious. I made 10 rockets in about 3 hours. The first thing you need to do is collect some 1 litre bottles. You want to use bottles that once held carbonated drinks. This type of bottle is built to withstand pressures of around 90psi. If you use plain water bottles, they will burst on the launch pad (more on the launcher later).

I used hot glue to attach 3 cardboard fins to each bottle. I tried to emulate the fin design of the famous V2 rocket that the Nazis used to terrorize Europe during WWII, but feel free to succumb to the influence of your own favorite weapon of mass destruction.

Be sure to rough-up the surface of the bottle with some sandpaper where you attach the fins, that way the glue will stick.

Next, I gave the rockets a quick shot of flat white spray paint. This will provide a nice blank canvas for your little Werner Von Braun’s to work with.

I topped the rockets with nosecones made from some light card stock hot-glued into place.

Decorate

Turn the little rocketeers loose with pens, tape, stickers, paint, etc. for as long as they remain interested, then head outside and launch some rockets!

The Launcher

Yeah, you’ll need a launcher. There are numerous launcher designs out there. A search will turn up many simple designs. I really liked the design of the Martinet Launcher, so I built one of those, but there are many other designs out there.

Launch ‘em

Whatever style of launcher you devise, the principal is the same. It’s just like a bigger and way better version of those little red plastic water rocket toys that you had as a kid. You’ll fill the bottle about 1/3 full with water, pressurize it with air, then realease it from the launcher. The air forces the water out through the nozzle, generating thrust and sending the rocket skyward.

See Make magazine vol. 5 for detailed instructions on building the launcher.

Trust me, this is on par with renting a bouncy-house, but a hell of a lot cheaper and more memorable.

This entry was posted on Sunday, September 23rd, 2007 at 8:58 pm and is filed under Easy Projects. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.