Make Your Own of Water Rocket

Water rockets are easy to make and use materials found in daily life. Children will be thrilled, and their creativity stimulated, watching their hand-made rockets soar skyward to unexpected heights. Water rockets that perform well have good science behind them. Similarly, behind every failure is a scientific concept that has been violated.So it is essential that children understand the fundamentals of water rockets. Water rockets have much in common with real rockets, allowing children to experience the same excitement that rocket engineers do. Several key points must be remembered if your students are to succeed in making water rockets that fly high, straight and safely – and enjoy themselves in the process.

Project by Prof. Nobuaki Ishii
Institute of Space and Astronautical Science Japan Aerospace Exploration Agency

Make Your Own of Water Rocket

Preparations for Making Water Rockets

This chapter will introduce the terminology for water rockets, as well as materials, tools and equipment needed to make the water rocket body and launcher.

Basics of water rocket

Terminology for the water rocket

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Basics of launcher

Terminology for the launcher
Launch gear :Hand-made device to launch the water rock-et It is made by attaching a ready-made join-ter (to set the nozzle onto) to a break bar of a bicycle.

Materials needed to make the water rocket and launcher

Essential materials and tools

Materials needed to build one rocket

2 PET bottles (for carbonated drinks).

Get two PET bottles that have been emptied, cleaned and dried, and had their labels removed. One bottle will be used for the rocket body, and the other to make the nose cone. While it is usually advisable to use 1.5-liter round (cylindrical) bottles, smaller 500-milliliter bottles can also be used.

However, the PET bottles must be for carbonated drinks, as these can withstand greater pressure than bottles used for non-carbonated drinks. Bottles must also be smooth and free from damage.

When launching your rocket, the air pressure should not exceed 7 atmospheres. For the sake of safety, we recommend 4~5 atmospheres. Technically speaking, only the bottle from which the rocket body will be fashioned needs to be for carbonated drinks since the rocket body, and not the cone, will be put under pressure. The other bottle, used for the nose cone, can be for other types of drinks. However, to avoid confusion during the rocket building process, it is better to use two carbonated drink bottles.

2 PET bottles (for carbonated drinks).

PVC sheet (or any thin sheet of flexible yet sturdy plastic) 10cm ×20cm

To make fins, get a sheet of PVC that is 1~2mm in thickness. You can find these at your local do-it-yourself outlet. If PVC sheets are unavailable, you can substitute them with any type of thin, flexible yet sturdy plastic, such as writing boards made of poly-styrene.
This is used to make the skirt. Available at your local stationery shop, etc.

Modeling clay approx. 50g

Modeling clay is used as ballast. If you will be mak-ing several water rockets at one time – for example, as a school project – it is advisable to prepare a suitable number of individual lumps of clay before-hand, each weighing about 50g.

Vinyl bag (as cushion: 45-liter capacity trash bag) 1 piece

A vinyl bag is put into the nose cone as a cushion to absorb the impact when the rocket returns to Earth. Please use one 45- to 70-liter vinyl garbage bag for each rocket.

Vinyl tape

Vinyl tape is used to put parts and materials togeth-er. By offering an assortment of tapes of various col-ors, children can combine them to create their own colorful designs.
As a safety precaution, we strongly recommend the use of mass-produced nozzles. While it is possible to use a rubber stopper, you run the risk of the stop-per failing as air pressure increases; such unpre-dictability makes them a poor choice as far as safety is concerned. Commercially available nozzles also can be used repeatedly.

Tools and equipment

While most of the cutting work can be done using a pair of common scissors, a cutter or specially designed pair of scissors with pointed tips is used to cut the nose cone from the second PET bottle.

We advise you to take every precaution when handling these tools.


The type of scissors as shown here is used for most of the cutting, such as for the fins, skirt and nose cone. Special PET bottle scissors are also available.


A cutter is used when making the nose cone. You are tasked with explaining to the children the proper way to hold the cutter, how to handle other tools, and other safety precautions to ensure that risk of injury is reduced to a minimum.

Cutter mat

When using the cutter, students should be given a mat to protect their desks.


If you will be making the rockets in a classroom, gymnasium, or other similar location you might choose to place a piece of plywood on each student's desk or on the floor to prevent damage to the desk or wood floor.

Permanent marker

A permanent marker is used to draw cut guidelines and names on PET bottles. The use of various color markers can enhance enjoyment of the building process as they allow your students to illustrate their rocket bodies.

Materials, tools and equipment needed build the launcher

The launcher we describe in this manual is simple to make and uses materials and tools encountered in your daily life. The launcher is designed to be adjustable, allowing you to adjust the launch angle as desired.

  • Wood slabs: 2 types each for the guide rail and base sections These wooden slabs constitute the core sections of the launcher. Strong and durable materials like waterproof plywood are recommended.
  • Square wooden rods: 4 pieces These square rods are used as guide rails.
  • Hinges: 2 pieces

Used to connect the wooden slabs for the base section.

  • Hooks and hetons: 2 pieces each

Used to connect the guide rail section to the base section.

  • Protractor, kite string, weight

Used to make the mechanism to determine the launch angle.

  • Chain: 1 piece

Used to fix the launch angle.

  • Nails, adhesive agent, vinyl tape
  • Oil-based varnish for application to wooden materials

Since the launcher we are going to make is made of wood, we coat its entire surface with var-nish to protect against water damage.

Tools and equipment

  • Hammer
  • Saw
  • Wood adhesive
  • Pencil

Rocket flow chart: from building to launch

Rocket flow chart: from building to launch

Watch Video

Water Rocket construction video part 2 by sci-tech

Part 2 Make Your Own Water Rocket

Part 2 Make Your Own Water Rocket

The water rocket body to be introduced in this article will be a basic type that can be made using readily available materials; this type achieves a balance between safety and functionality.

We suggest that you begin by building a water rocket following the process suggested here so that your students can learn the basics of rocket making. After they have mastered the basic design, you can encourage your students to exert their ingenuity in the pursuit of new designs.

What you will need

Assemble the necessary materials and tools and run through the checklist before starting your class/workshop.

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2 PET bottles PVC sheet ,File holder (Clear file), Vinyl bag (trash bag) , Modeling clay , Nozzle , Permanent magic marker (oil base) , Cutter , Scissors , Cutting mat , Vinyl tape, Scale

Water rocket building process

1. Making fins

Cutting out fin patterns Various shapes of fins can be made in height and width. Let’s make 4 fins of the pattern at left.
Using a permanent magic marker, draw fin pattern guidelines on a plastic sheet as shown in the illus-tration at left, then carefully cut out the patterns fol-lowing the guidelines.

2 Preparing the fin base

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Bend the anchors to the left and right by aligning the ruler.

Divide the base of each fin into four equal parts by drawing and then cutting three guidelines. Alternately bend the anchors to the left and right.

You can ensure a straight bend by aligning the ruler along the baseline. Repeat this process for each one of the four fins.

Make 4 fins in the same manner

3.Making the skirt and attaching it to the rocket body

Cutting out the skirt section from a file holder (clear file)

Cut the clear file into a rectangular shape :The width : Wrap the clear file around the pet bottle and add a few centimeters to overlap at the leading edge.The length : Wrap the sheet around the pet bottle and adjust its length so that the cylinder is slightly longer than the bottle’s mouth.

Wrapping the skirt material around the rocket body

Having cut out the skirt, wrap it around the rocket body and use a magic marker to mark the position
where the two edges overlap.

4. Dividing it into four equal parts and making creases

Spread the rectangle flat again and divide it into four equal parts, using the previously marked line as a reference point. First fold the sheet into halves, then fold each half into quarters. Mark each quarter and make creases.

Dividing it into four equal parts and making creases

5. Making cuts along the creases and marked line

Make cuts along the creases and the marked line to divide the rectangle into four equal parts.

Making cuts along the creases and marked line

6. Attaching the fins

Insert the fins one by one into the skirt, then tape the slots securely from the reverse side of the skirt.

Attaching the fins
Attach the fines to the skirt

7. Affixing the skirt to the rocket body

Wrap the skirt around the rocket body and fasten its starting edge with vinyl tape, then use more tape to firmly fix the skirt at its leading edge Check to see the skirt is fixed in the right position Check the skirt position to ensure that it extends beyond the end of the PET bottle’s mouth.

Affixing the skirt to the rocket body

Making the nose cone

1 Marking the other bottle with cut guides

The second bottle is used to make the nose cone. Use the permanent magic marker to mark cut guide-lines for the part that will become the nose cone.

Marking the other bottle with cut guides

2. Making partial cuts with a cutter

As shown in the photo, use the cutter to make partial cuts into each guideline. This is a safe way to open gaps for the use of scissors.

Making partial cuts with a cutter

3. Cutting along the guidelines

Use the scissors to cut off the nose cone. We have found that it is easier to remove the part near the bottle cap first.

Cutting along the guidelines

4. Attaching the nose cone

Weigh out about 50 grams of modeling clay and apply it to the bottom of the rocket’s body

Attaching the nose cone

5. Determine the center of gravity

Place the rocket on your forefinger to determine the center of gravity. The center of gravity should be closer to the nose cone and not the actual physical center of the PET bottle.

Determine the center of gravity

6. Attaching the nose cone

Attaching the nose cone

Push the nose cone over the rocket body and tape it securely into place.

7. Putting the vinyl bag into the nose cone

The vinyl bag acts as a cushion inside the nose cone. Unfold the vinyl bag and stuff it loosely into the nose cone.

Putting the vinyl bag into the nose cone
Sealing the nose cone

Prepare 10 to 15 strips of vinyl tape of a uniform length and use them to seal the nose cone opening.

Final check

The final step is to check the rocket thoroughly to ensure that it is not warped or otherwise damaged, and that all parts are firmly fixed. Attach the nozzle and check the length of the skirt if the top of the nozzle protrudes slightly from the skirt.

Final check

  • Make Your Own water Rocket Launcher

Watch Video Part Two Construction of Water Rocket

Abdul Rauf

Teacher, Innovator, Love to create, explore new ways to view & imagine things and then make them real

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