People have been making and launching water rockets for generations. Some of the people most passionate about this hobby have spent years perfecting their rocket designs and there are thousands of different ways to make one. It can be a bit intimidating to make your first rocket out of a bottle, with all the technical information that is available. The principle is very simple, and making a rocket out of a bottle doesn't involve a long list of things you have to buy at a hardware store.
Steps
Method 1 of 3: Make a Rocket
Step 1. Make a cone out of a sheet of paper
This will give the rocket more flight stability. It is also a very important decorative element for your rocket to look like a rocket ship, so be sure to choose a paper color that you like.
- Draw a circle that is 1 foot (30 centimeters) in diameter. The measurement does not have to be precise, you can always adjust the size later. The easiest way to do this is to find a good-sized bowl, place it face down on the sheet of paper, and trace the outline.
- Cut the circle and cut a straight line from the outside to about the center of the circle. Again, it doesn't have to be precise, just as far as you think the center is.
- Slide the edges of the cut over each other to create the cone. Hold it over the cone to see if it is the correct size, then tape or glue the ends together to hold the shape.
Step 2. Cut three charcoal fins
As with the cone, these will help stabilize the flight and make your rocket look more like a rocket. There is no one correct way to make the fins, they just have to look like scalene right triangles (the sides are all different lengths) with the second longest side of the triangle attached to the sides of the rocket.
You have to decide the exact dimensions of the fins. Start cutting out a cardboard triangle and clip it to the side of the rocket to see if you like the way it looks. Adjust the shape until you are satisfied, and then trace the fin you just made twice on the cardboard to have two more identical triangles
Step 3. Attach the spout and fins to the bottle
The paper cone goes to the bottom of the bottle. The fins go to the middle of the body, spaced equal distances from each other around the circumference. Use a not-too-hot glue gun to avoid melting the plastic.
Method 2 of 3: Make the Launch Pad
Step 1. Cut the bottom of the oatmeal can
You can also use any other can of food or a piece of PVC pipe. Just make sure it's the right width for the bottle to fit inside the can and not too tight, with the neck of the bottle (the bottom of the rocket) pointing down. This will serve as a launch pad for your rocket.
Step 2. Tape a dowel or garden stake to the side of the can
You'll drive that stake into the ground to stabilize the pitcher, so it should come out about 0.5 to 1 inch (15 to 30 centimeters) from the can. Just make sure you stick it firmly in place.
Step 3. Drill a small hole in the cork
Use the smallest drill you can find. This hole needs to allow the air pump needle to smoothly enter the cork and exit the other side so that you can pump air into the rocket.
- Artificial cork works wonders for this project, as real cork tends to crumble.
- The cork is most likely too long, so you need to cut it a bit so that the needle goes through the entire length of the cork.
Step 4. Assemble the pieces
Pass the nozzle of the air pump through the can so it comes out the top. Put the needle of the air pump through the hole in the cork.
Method 3 of 3: Launch the Rocket
Step 1. Put water in the bottle and seal it
Fill the bottle 2/3 full with water. Insert the cork (once attached to the air pump) into the nozzle of the bottle. It needs to be as tight as possible for it to work, so make sure you insert it well into the mouthpiece and that it doesn't come off easily.
Step 2. Prepare for take off
Pull the excess air pump tubes out of the oatmeal can. Place the rocket on top of the can and drive the garden stake as far into the ground as you can, so that the bottom of the can is on the ground. Get away.
Step 3. Increase the pressure inside the rocket
Start pumping air into the rocket with the air pump. It will not be long and the pressure of the rocket should increase to the point that the rocket will fly into the sky.
If the rocket does not fly, it is most likely because it is not well sealed. Make sure there are no holes in the bottle. If there are holes, fix them with tape. If there are no holes, the cork may not be tight enough on the spout of the bottle. Try applying hot glue or industrial glue around the nozzle of the bottle. It is also likely that the hole you made in the cork is very large, if so you have to find another cork and make a smaller hole
Warnings
- Remember to always be very careful with hot glue guns. Have a cup of ice handy in case you burn your finger, you can immediately apply ice to the burn. Unplug the gun as soon as you're done.
- Get as far away from the rocket as possible as the air bomb allows, and make sure any bystanders are at least 10 feet (3 meters) away when you launch the rocket.