Water Bottle Rockets

This summer has been a fun one. Lots of time spent at our local Lake Nokomis Beach. Although water quality isn't what it should be here in the Twin Cities Lakes this year, it has been nearly impossible to stay cool without going for a dip in the lake. HOWEVER...there are other ways...

Recently I taught a class for some kids as part of a summer camp at Leonardo's Basement. The course title was "3,2,1 Water Blastoff!!!." The above rocket was made by the assistant in the class. As you can imagine, it was alot of fun and I found a pretty cheap and easy way to get wet. A PVC water bottle rocket launcher powered by a bicycle pump is not hard to build at all and cheap. I'd say you could find some things in your tool box at home. The rest you can buy for under $20. It comes apart in two easy to carry parts like so:

Here's list of materials you'll probably find at home. You can also go to the link at the bottom of the list if you need more explanation. Just click on Materials List and you'll be all set to go. Here's mine.

List at Home
-Duct tape
-2 two litre bottles
-candle
-hacksaw
-bike pump
-marker
- 3 feet of rope (strong shoelace works)
-drill with 1/2 inch drill bit and a smaller sized bit to fit the twine or shoelace
-tape measure
-scissors


Materials at the store:
-1/2 inch PVC schedule 40 pipe - 10ft section--this fit in the Buick, but you can cut it at 4ft at the store
-short piece of 1 1/2 inch PVC (2 inches long)
-1/2 inch slip tee connector
-2 pieces 1/2 inch slip end caps
- 1/2 inch slip and internal thread
- 1/2 inch slip and external thread
- roll of teflon tape (plumbers tape)
- PVC primer (don't need to have this, but i used it anyway)
- PVC cement
- hose clamp that opens to at least 1 inch
- 8 plastic zip ties
- tire valve from O'Reilly's or auto parts store of your choice. You don't need the expensive threaded kind and you want the thin kind if they offer more than one type.
- you can get a tire pressure gauge if you want


In building my rocket launcher I found the videos at this link very helpful. Same spot i got the materials list from. The videos are very well done and easy to understand so I'm not going to go into too much depth explaining the instructions. The site is very thorough.

Basically you are going to be cutting up the PVC tubing into specific lengths with the hacksaw. You'll be drilling a 1/2 inch hole in one of the end caps to put your tire valve into. Then you'll be gluing your parts together.

Next you've got to create a bump in the pipe so your water bottle rocket will stick on the pipe without leaking. This is probably one of the trickier spots. You've got to melt the pipe with the candle at a specific length to form the bump. There are other ways (o-rings) to make the seal air tight, but this is probably the most effective.

Then you've got to build your trigger mechanism using duct tape, zip ties, shoelace, and the small piece of 1 1/2 inch pipe.

You'll have to line that up with the bump in the pipe you created and tighten it down with the hose clamp. After that you build your safety spring with one of the two liter bottles. Attach one piece of leftover piping to keep that from sliding down, set up your trigger, slide on the remaining 1/2 full 2 litre bottle of water, fix the trigger, pump and let 'er rip!!!