|2-Liter Bottle Rocket|
2 liter plastic bottle
Bicycle Tire Pump
Needle for pumping up balls
1/4" diameter metal rod
For other activities, see the Activities Chapter.
These are fairly safe rockets that are a lot of fun in warm weather. The rocket can go 60 or more feet into the air.
Let's start with the launch pad. You could make a fancy launch pad, but pushing the 1/4" metal rod into the ground works just as well.
The propulsion system (bicycle pump, needle, and stopper) is easy to construct also. Drill a 1/16" hole all the way through the rubber stopper. Push the needle into the large end of the stopper. Note that water may drain back into the pump and rust it. Be sure to clean out the pump after each use.
The rockets are made by duct taping a piece of straw (6" long) to the side of a 2-liter bottle. Lay the straw in the middle of the duct tape and attach it to the bottle. Make sure the straw is straight, not tilted with respect to the bottle. That's all you really need for a rocket, but children may want to decorate them more. To make the fins, cut out three triangles from stiff paper or poster board. Color them as desired. Use a strong clear tape or duct tape to attach the fins to the 2-liter bottle. Cut half of a circle about 8" in diameter out of paper. Roll it into a nose cone and tape it. Color it as desired. Tape it to the top of the rocket using rolls of tape (sticky side out).
To launch the rocket, fill the bottle one-fourth to three-fourths full of water. You might want to experiment to see what the best amount is. Push the rubber stopper firmly into the bottle mouth. Attach the pump to the needle. Place the rocket on the metal rod. Make sure no one stands over the rocket. Start pumping. Pressure will build up in the bottle until the rocket jumps into the air on a column of water. The person pumping in almost guaranteed to get wet. Be careful not to get hit by the falling bottle. Even though they don't weigh much, it still can hurt.