How to make an origami water balloon
This page has a UK and a US version. UK version of this page
The traditional water bomb is a flat paper shape that puffs up into a ball when you blow into it. It starts with the waterbomb base and ends with two tricky tucks into hidden pockets – a great challenge for confident folders.
- Tricky
- Age 8+
- About 20 minutes
- 11 steps
- No scissors
- Moves: Watch it bounce
Lesson at a glance
- You need
- A square of thin paper (15 cm or 6 inches). No scissors or glue.
- Time
- About 20 minutes (allow longer the first time)
- Level
- Tricky · age 8+
- How to teach it
- Show the 3D folder on the board and pause after each step, or print the step sheet for each table. Both show the same folds.
Finished!
Step 1 of 11Start with the square white side up. Fold it in half from corner to corner, open it, then fold and open the other diagonal.
Keys: left and right arrows go back and forward, Space plays or pauses, R plays the step again, B shows the back. On the 3D picture, the arrow keys turn it and + and − zoom.
How to fold a water balloon: step by step
You need: one square of thin paper, 15 cm (6 inches) is ideal. Origami paper or thin printer paper works best – thick paper will not puff up. To make a square from A4 or US Letter paper, fold one corner down to the opposite edge, crease the strip that is left over firmly both ways and tear it off carefully.
Start with the square white side up. Fold it in half from corner to corner, open it, then fold and open the other diagonal.
Turn the paper over. Fold it in half from top to bottom and open it again.
Turn it back over. Push the ends of the middle crease in towards the center and let the top half fold down over them. Flatten it into a triangle. This is a waterbomb base.
Fold the bottom corners of the front flaps up to meet the top point. The front is now a small square standing on one corner (a diamond).
Turn it over and do the same on the back: fold both bottom corners up to the top point.
Fold the left and right corners of the front flaps in to meet at the middle line.
Fold the two small loose points at the top down, along a line level with the top corners of the side folds.
Fold each little point again and tuck it into the pocket of the side triangle below it. Push it right in so it holds.
Turn it over. On this side too, fold the left and right corners in to meet at the middle line.
Fold the two little points at the top down, then fold them again and tuck them into the pockets, just as you did on the first side.
Find the little hole at the bottom point. Hold the water balloon loosely, blow hard into the hole and watch it puff up into a ball!
Finished!
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How to make it move
- Blow it up: hold the water balloon loosely by its sides, put your lips to the little hole at the bottom point and blow one short, hard puff. The flat shape pops out into a fat ball. Gently pull out the corners to help it.
- Bounce it: tap it up into the air with your palm, like a balloon, and see how many taps you can do before it lands.
- Make it rounder: push the corners in a little and blow again. Thin paper puffs up more than thick paper.
- Why it is called a water bomb: in Japan this toy is called a paper balloon. Its English name comes from filling it with water – please keep that for outdoors, and only if your school allows it!
If it goes wrong
- The waterbomb base will not collapse (step 3): check that the diagonals were folded on one side and the middle crease on the other. Turn the paper so the middle crease forms a little hill, then push its ends in.
- The flaps do not reach the top point (steps 4–5): fold only the front flap each time, not the whole thickness, and make sure the base was flattened neatly.
- The points will not tuck in (step 8): fold the little point down first and crease it hard, then open the pocket slightly with a fingernail before you slide the point in.
- It will not puff up: the hole is squashed shut or the paper is too thick. Open the hole with a pencil tip, blow one short hard puff and pull the side corners gently.
What kids learn
- From 2-D to 3-D: a flat net becomes a solid shape. Talk about faces, edges and corners (vertices) before and after it is blown up.
- Air takes up space: blowing in pushes the paper walls outwards – air is a material, even though we cannot see it.
- Bases in origami: the waterbomb base is used in many other models, such as our jumping frog.
- Precision: the tucks only work when every fold is accurate, so students see why careful measuring matters.
Classroom tips for teachers
- Demonstrate the base first: fold the waterbomb base together, paused on the board, before anyone starts the flaps.
- Big paper for the tucks: 20 cm squares make the pockets easier to find. Origami paper is better than printer paper.
- Science link: compare water bombs made from different papers. Which puffs up best? Which bounces most times?
- Math link: unfold a finished model and count the triangles in its crease pattern. Which fractions of the square can you find?
- SEND tips: give out squares with the base already folded, and let students work in pairs for the tucking steps. Keep the blowing-up step individual and hygienic.
Standards links
- Math (1.G.A.2, 2.G.A.1): compose 3-D shapes and identify their faces, edges and vertices.
- Math (6.G.A.4): connect a flat net with the solid it makes.
- Science (NGSS 5-PS1-1): develop a model to show that air is matter made of particles too small to see.
- ELA (SL.3.1): explain each step to a partner using precise words.
Links to the Common Core State Standards, NGSS and the National Core Arts Standards. Check against your own state’s standards.
Safety
No scissors or glue are needed. Each child should blow up only their own water bomb, and should not share them mouth to mouth. Play with it in a clear space, away from faces. Do not fill it with water indoors.
More origami to try
More for your classroom
Frequently asked questions
Why won’t my origami water bomb puff up?
The hole may be pressed shut or the paper may be too thick. Open the hole gently with a pencil tip, blow one short hard puff and pull the side corners outwards a little.
What is the difference between a water bomb and a waterbomb base?
The waterbomb base is the triangle you make at step 3. Lots of models start from it. The water bomb is the finished paper balloon.
Can you really fill it with water?
Yes, a well-folded water bomb holds water for a short time, which is how it got its name. Keep that for outdoors and check your school’s rules first.
What paper should I use?
A thin square of origami paper, 15 cm (6 inches) or bigger. Thick card will not puff up.