Rockets illustrate Newton's third law: "For every action, there is an equivalent and opposite reaction." The first rocket is believed to be a steam-powered wooden pigeon invented by the Archytas of Tarentum in the 4th century BC. Steam was replaced by gunpowder tubes by the Chinese and by liquid fuel in rockets devised by Konstanin Tsiolkovsky and Robert Goddard. This article will teach you five ways to build your own rocket, from the simplest to the most complex. At the end of the article you will find an additional section that explains some of the principles that guide the construction of these rockets.
Method 1 of 5: Bladder Rocket
Step 1. Tie the end of a sewing or fishing line to a support
Possible supports include chair backs and door handles.
Step 2. Pass the thread through a straw
These items will act as a steering system to guide the rocket's path.
Miniature rocket kits usually have a straw attached to the body of the rocket. This straw is passed through a metal pin on the launch pad to keep the rocket straight
Step 3. Tie the other end of the thread to another support
Stretch it out well before tying it.
Step 4. Inflate the bladder and hold the tip of the bladder to prevent air from leaking
You can use your fingers, a paper clip or a clothes peg.
Step 5. Glue the bladder to the straw
Step 6. Release the air from the bladder and the rocket will travel from one end of the line to the other
- You can experiment with different types of bladder and straw to see how the rocket travels. You can also change the angle of the line to see how it affects the distance covered.
- You can create a boat in a similar way: Cut a milk carton in half lengthwise. Punch a hole in the base and pass the tip of the bladder through it. Fill the bladder and place the boat in a bathtub before releasing the air to make it move.
Method 2 of 5: Straw Rocket
Step 1. Cut out a rectangular strip of paper
Its length should be three times its width: suggested dimensions are 12 cm by 4 cm.
Step 2. Wrap the strip securely around a pencil or pin
Place it near the tip of the pencil, as part of it should be beyond the edge.
Use a pencil or pin that is a little thicker than a straw, but not too much
Step 3. Glue the end of the strip to prevent it from coming off
Put a duct tape along the length.
Step 4. Fold over the remainder to create a tip or cone
Glue the beak so that it retains its shape.
Step 5. Remove the pencil or pin
Step 6. Check that there is no air leak at the tip of the rocket
Try to hear the noises of air leaking from the side or nozzle of the rocket while watching the joint to see if there is any movement caused by the blow. Plug leaks and retest until there are no more leaks.
Step 7. Add wings to the open part of the rocket
As this model is narrow, it may be easier to add the wings in pairs rather than placing them one by one.
Step 8. Insert a straw into the open side of the rocket
Make sure it extends beyond the rocket so you can pick it up with your fingers.
Step 9. Blow hard into the straw
The rocket will fly, propelled by its breath.
- Always aim the rocket upwards and never aim it at anyone.
- Vary how the rocket builds to see how it affects its flight. You can also vary the intensity of the breath to see how this changes the distance covered.
- A toy similar to this rocket consists of a stick with a plastic cone at one end and a plastic parachute at the other. The parachute must be folded over the rod, which must be inserted into a cardboard tube. After blowing the tube, the cone must launch the rod which, after reaching the maximum height, will fall, opening the parachute.
Method 3 of 5: Photo Roll Container Rocket
Step 1. Decide the desired length of the rocket
A good measure is 15 cm, but it is possible to assemble the larger or smaller rocket if you wish.
A good diameter is 4 cm, but this measurement will be determined by the diameter of the rocket's combustion chamber
Step 2. Get a photo roller container to be the combustion chamber
Look for containers at developers and photo studios that still shoot on film.
- Look for a container whose lid has an internal rather than an external lock.
- If you cannot find a container, you can use an empty medicine bottle with a snap-on lid. If you can't find one of these too, carve a cork stopper that will fit into the mouth of the bottle.
Step 3. Assemble the rocket
The easiest way to do this is to wrap a strip of paper around the container, as you did with the pencil when making the straw rocket. Since the roll container will launch the rocket, glue the end of the paper together before rolling it up completely.
- Remember to point the container's mouth outward when attaching the rocket frame to it. The mouth will serve as a mouthpiece for the rocket.
- Rather than bending the tip of the rocket out of the container, creating a cone, you can create a separate nozzle by cutting out a circle of paper, making a cut from the edge to the center of it, and folding it into a cone. Then secure the cone with tape or glue.
- Add wings. Since this rocket is wider than the paper model, cut out and attach the wings individually. You can also opt for three wings instead of four.
Step 4. Decide where you want to launch the rocket
An open location is recommended as the rocket can reach considerable height after launch.
Step 5. Fill 1/3 of the container with water
If the water source is not close to the launch base, carry the rocket upside down or carry the water in a bottle to fill the container at the launch site.
Step 6. Break an effervescent tablet in half and pour half into the water
Step 7. Cover the container and turn the rocket on the right side over the launch pad
Step 8. Stay at a safe distance
As the tablet dissolves, it releases carbon dioxide. Pressure will build up until the container lid explodes, launching the rocket.
Instead of water, you can fill half the container with vinegar. In place of the effervescent tablet, you can use a teaspoon (or 5 grams) of baking soda. Vinegar, an acid (acetic acid), reacts with baking soda, a base, to produce water and carbon dioxide. These items are more volatile than water and effervescent tablets, so move away from the rocket more quickly – and be careful not to overdo the ingredients or you could explode the container
Method 4 of 5: Matchstick Rocket
Step 1. Cut out a small triangle from aluminum foil
The triangle should be isosceles, with approximately 2.5 cm at the base and 5 cm from the center of the base to the apex.
Step 2. Take a matchstick
Step 3. Align the toothpick against a pin
Position them so that the tip of the pin touches the thickest part of the toothpick head.
Step 4. Wrap the aluminum triangle around the toothpick head, starting at the top end
Wrap it tightly, but be careful not to move the pin. When finished, the triangle should extend beyond the head by about 6 mm.
Step 5. Use your fingernails to press the foil against the match head
This will bring the coverage closer to the head and better define the channel formed by the pin.
Step 6. Carefully remove the pin from the aluminum
Be careful not to tear the paper.
Step 7. Fold a paper clip to make it into a launch pad
- Bend the outer fold to a 60° angle. This will form the basis of the launch pad.
- Fold the inner fold up and down to form an open triangle. This is where you will support the match head.
Step 8. Place the launch pad where you want to launch the rocket
It is recommended to opt for an outdoor location, as this rocket can travel considerable distances. Avoid very dry places as the toothpick could start a fire.
Clear the area around the rocket before launching it
Step 9. Place the rocket on the launch pad with the tip up
It must support at a 60° angle. If the angle is smaller, adjust the fold of the paper clip.
Step 10. Launch the rocket
Light a match and place its flame under the head of the match wrapped in aluminum foil. The rocket must be launched when it is lit.
- Have a bucket of water on hand to completely extinguish the rockets.
- If a rocket lands on you, stop moving, drop to the ground and roll until the fire is out.
Method 5 of 5: Water Rocket
Step 1. Prepare a two liter PET bottle to serve as a pressure chamber for the rocket
Since this rocket is created from a bottle, it is known in some places as a bottle rocket. There is a firework with a similar name, but it is banned in several places. The rocket taught below is not illegal.
- Remove the label from the packaging by cutting it where it does not stick. Be careful not to scrape or puncture the bottle so as not to weaken it.
- Reinforce the bottle with strong adhesive tape. Current cylinders can withstand pressures of up to 7 kilograms per square centimeter (or 689.48 kilopascals), but repeated releases will reduce the amount of pressure supported without the bottle breaking. Glue several loops of tape around the center of the bottle and halfway to the ends.
- Mark the points where you want to fix the wings with a marker. If you plan to use four wings, draw lines 90 degrees apart. If you want to use five wings, draw lines 120° apart. Wrap a strip of paper around the bottle and make the marks before transferring them to the bottle itself.
Step 2. Build the wings
Since the plastic rocket is relatively durable, however reinforced it is, you'll need durable wings. Firm cardboard may work for a while, but the plastic used in folders and filing cabinets is a better option.
- First you will need to design the wings and create a cut pattern. No matter how you draw them, make a mold that can be folded in half to reinforce it so that it touches at least the point where the bottle tapers.
- Cut out the template and use it as a guide to cut the wing material.
- Fold the wings and secure them to the rocket body with masking tape.
- Depending on the launcher's design, it may be best not to create wings that extend beyond the mouth of the rocket's bottle/mouthpiece.
Step 3. Create the rocket nozzle and weight section
You will need a second two liter pet bottle for this.
- Cut out the base of the bottle.
- Place a weight on the top section of the cut bottle. Use a piece of modeling clay or a ball of rubber bands. Place the lower section inside the upper, with the base facing towards the mouth of the bottle. Stick them in place and insert them into the base of the bottle that serves as a pressure chamber.
- The beak can be made of anything. You can use anything from a bottle cap to a PVC or plastic tube. After choosing what you want, permanently attach it to the cut top section of the bottle.
Step 4. Test the rocket's balance by resting it on your index finger
It must balance above the pressure chamber (the base of the first bottle). If not, remove the weight section and adjust it.
After locating the center of mass, weigh the rocket. It should weigh somewhere between 200g and 240g
Step 5. Create the launcher/stopper
There are several devices that can be used to launch the water rocket. The simplest is a valve and a stopper that fit in the mouthpiece of the pressure chamber.
- Find a stopper that fits snugly into the mouth of the bottle. You might need to cut it a bit.
- Get a valve system like those used on car and bicycle tires. Measure its diameter.
- Drill a hole in the center of the stopper using a drill the same diameter as the valve.
- Clean the valve stem and place a piece of tape over the notched portion and opening of the valve.
- Screw the valve into the hole in the stopper and seal it in place with a silicone or urethane sealant. Allow the seal to dry completely before removing the tape.
- Test the valve to make sure air passes freely through it.
- Test the stopper by placing a small amount of water in the pressure chamber, fitting the stopper, and placing the rocket upright. If you find any leakage, reseal the valve and test it. After making sure there is no leakage, test again to determine the pressure needed to remove the stopper from the bottle.
- For instructions on how to build a more sophisticated launch system, go to
Step 6. Choose a launch location for the rocket
As with the film reel and matchstick rocket, an open location is recommended. As the water rocket is bigger than the others, you will need an even larger and more level area.
A raised surface, such as a picnic table, is great for situations where small children are involved
Step 7. Launch the rocket
- Fill between 1/3 and 1/2 of the pressure chamber with water. (You can add some food coloring to produce a colored "exhaust" at launch). It is also possible to launch the rocket without adding water to the chamber, but the pressure required may be different and will need to be measured again.
- Insert the launcher/stopper into the mouthpiece of the pressure chamber.
- Connect the hose from a bicycle pump to the release valve.
- Place the rocket upright.
- Pump the air until you reach the pressure at which the stopper will be expelled. There may be a slight delay before she is kicked out and the rocket is launched.
The Rocket Parts and How They Work
1. Use the booster to lift the rocket and move it through the air
A rocket flies by directing an exhaust stream downward through one or more nozzles. Rocket engines work by mixing the fuel with a source of oxygen (an oxidant), which allows them to work in space and the Earth's atmosphere.
- The first rockets were powered by solid fuels. These types include Chinese fireworks and war missiles, as well as the thin rockets used by spacecraft. Most of these models have holes in the center for fuel and oxidizers to meet and combust. Engines used in miniature rockets use solid fuel thrusters in conjunction with various charges to release the parachute after the fuel runs out.
- Rockets that use liquid fuels have separate pressurized tanks with fuels such as gasoline or hydrazine and liquid oxygen. These materials are pumped into a combustion chamber at the base of the rocket; the exhaust is then released through a conical mouthpiece. The main thrusters of space rockets were liquid fuel rockets supported by an external fuel tank loaded under the shuttle at launch. The Saturn V rockets on the Apollo mission were also liquid fuel.
- Many ships use rockets to change direction in space. These rockets are called maneuver thrusters. The service module attached to the Apollo spacecraft's command module and the maneuvering backpacks used by the astronauts also had these thrusters.
2. Cut the air heater with the conical nozzle
Air has mass, and the denser it is, the more it holds objects that try to move. Rockets must be streamlined (with elongated, elliptical shapes) to minimize the friction encountered when navigating through the air, which causes them to have pointed beaks.
- Rockets that carry payloads (astronauts, satellites, or warheads) typically carry them close to the beak. Apollo's command module, for example, was conical.
- The conical nozzle also charges the rockets' guide systems to prevent them from going off course. These systems can include on-board computers, sensors, radars and radios to provide information and control the course of flight. (Goddard rockets utilize a gyroscope control system.).
3. Balance the rocket around its center of mass
The overall weight of the rocket must be balanced around a certain point to ensure flight without a fall. This point can be referred to as equilibrium point, center of mass or center of gravity.
- The center of mass varies from rocket to rocket, but in general it is somewhere above the pressure or fuel chamber.
- Although the charge helps to raise the center of mass above the pressure chamber, too heavy a charge will cause the rocket's weight to be concentrated at the top, making it more difficult to hold it upside down before launch. Therefore, integrated circuits have been incorporated into the ships' computers to reduce their weight (this technology has led to the use of chips in calculators, wristwatches, personal computers and, more recently, tablets and smartphones).
4. Stabilize flight with wings
The wings ensure that the rocket's flight is straight, creating air resistance against changes in direction. Some wings are designed to extend beyond the rocket's mouthpiece and to keep it upright before launch.
In the 19th century, British William Hale devised another way of using wings to stabilize flight. He created exhaust ports next to weathervane-shaped wings that pressed on the gases and rotated the rocket to keep it from going off course. This process is called spin stabilization
- If you have fun making any of the above rockets, but want a bigger challenge, try the hobby of assembling miniature rockets. These rockets have been sold since the late 1950s in assembly kits and can be launched with black powder engines to heights of 500 meters.
- If it's difficult to launch a rocket vertically, mount it on rails to launch it horizontally (in essence, a balloon rocket is a rail rocket). You can attach the photo film container to a toy car and the water rocket to a skateboard. You will still need to find an open area with enough space.
- Adult supervision is recommended when dealing with rockets launched by something stronger than human breath.
- Always wear eye protection when launching flying rockets (any rocket other than a bladder). For larger rockets, such as water rockets, a helmet is also recommended.
- Never aim the rocket at another person.