Make a shampoo bottle boat - Fun at-home activities for Kids.

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Make a shampoo bottle boat

Build a small boat from an empty shampoo bottle, add a sail or motor, test buoyancy and speed, and learn simple engineering.

Table of contents

Step-by-step guide to make a shampoo bottle boat

What you need

Empty shampoo bottle, waterproof tape, modelling clay or putty, wooden skewer or sturdy straw, paper or thin plastic for a sail, scissors, string, rubber band, craft stick or small plastic propeller (optional), tub or sink with water for testing, adult supervision required

Step 1

Rinse the empty shampoo bottle thoroughly with water to remove any soap residue.

Step 2

Dry the bottle completely with a towel or let it air dry until no water remains.

Step 3

Replace the cap tightly on the bottle so it is closed.

Step 4

Wrap waterproof tape around the cap and neck to seal any tiny gaps and stop leaks.

Step 5

Press a small lump of modelling clay into the bottom inside the bottle to act as ballast and help it sit steady.

Step 6

Place the bottle gently in a tub or sink of water to check if it floats level.

Step 7

If the bottle tips or sinks, add or reshape small pieces of clay until the bottle floats upright and steady.

Step 8

Decide whether you want to add a sail or a rubber-band motor and do only the steps for the choice you picked.

Step 9

(Sail) Cut a rectangle from paper or thin plastic about the height of the bottle to make a sail.

Step 10

(Sail) Tape one long edge of the sail to the skewer or straw so the sail is firmly attached.

Step 11

(Sail) Push the skewer carefully through a small hole in the cap or tape the skewer to the bottle top so the mast stands upright.

Step 12

(Motor) Make a simple rubber-band motor by looping a rubber band around a small craft stick or plastic propeller and winding it so it can spin when released.

Step 13

(Motor) Tape the rubber-band motor to the back of the bottle so the propeller sits in the water and can turn freely.

Step 14

Launch your finished boat three times from the same start point and count seconds to compare which run was fastest.

Step 15

Share a photo and what you learned about buoyancy and speed with your finished shampoo bottle boat on DIY.org.

Help!?

What can I use if I don't have waterproof tape or modelling clay?

If you don't have waterproof tape, wrap duct tape or clear packing tape around the cap and neck (step 4), and if you lack modelling clay press rolled-up aluminum foil, small coins, or pebbles into the bottom as ballast (step 5).

My boat keeps tipping or taking on water — what should I check and fix?

If the bottle tips or sinks, reshape or add small pieces of modelling clay inside the bottom to adjust ballast (steps 5–6) and check the cap is tightly replaced and sealed with tape around the neck to stop leaks (steps 3–4).

How can I adapt this activity for different ages?

For toddlers, have an adult rinse and seal the bottle and pre-cut and tape a paper sail (steps 1–4 and sail steps), while older kids can build the rubber-band motor themselves (motor steps) and time three launches to analyze which run was fastest.

How can we extend or personalize the experiment beyond making a simple boat?

Decorate the shampoo bottle with waterproof markers, test different sail sizes or materials (sail steps), and change ballast amounts (steps 5–6) or rubber-band tensions (motor steps) to compare effects on speed across your three launches.

Watch videos on how to make a shampoo bottle boat

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DIY Toy Boat: How to Make a Fun Boat with a Recycled Plastic Bottle! KidiesTime7

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Facts about buoyancy and simple engineering

🧴 An empty shampoo bottle floats because the air trapped inside lowers its overall density below water.

⚖️ Archimedes' principle explains buoyancy: the upward force equals the weight of the water the boat pushes aside.

🌬️ Even a tiny sail on a lightweight bottle boat can catch enough wind to move it surprisingly fast across a pond.

🚤 Hobby model boats and RC speedboats can reach speeds over 100 km/h — small things can be very speedy!

♻️ Upcycling a shampoo bottle into a boat keeps plastic out of landfills; many plastics take hundreds of years to decompose.

How do I build a shampoo bottle boat and test its buoyancy and speed?

Start by rinsing and drying an empty shampoo bottle and tightening the cap. Add ballast (modeling clay, coins, or washers) near the bottom for stability. Create a mast from a skewer or straw and attach a paper or foam sail with tape or hot glue. Seal any holes with waterproof tape. For speed, try a rubber-band propeller or a small waterproof motor mounted securely. Test in a bathtub or pool, then adjust weight and sail position until it floats straight and moves well.

What materials do I need to make a shampoo bottle boat?

You’ll need an empty rinsed shampoo bottle with cap; waterproof tape or glue; modeling clay, coins, or washers for ballast; wooden skewers, straws, or craft sticks for a mast; paper, foam, or fabric for a sail; scissors and a craft knife (adult use only); tape or hot glue; optional rubber-band propeller or small waterproof motor and battery. Have markers or waterproof paint to decorate, plus a tub, sink, or pool for testing.

What ages is building a shampoo bottle boat suitable for?

This activity suits ages 4–12 with appropriate adult supervision. Ages 4–6 enjoy simple sail boats with help cutting and taping. Ages 7–10 can build more independently, add ballast, and try rubber-band propellers. Ages 11+ can experiment with small motors, hull trimming, and engineering tweaks. Always supervise use of sharp tools, small parts, batteries, and any water testing to ensure safety and learning.

What are the benefits of making shampoo bottle boats and how can I keep kids safe?

Making shampoo bottle boats teaches basic engineering, buoyancy, problem-solving, creativity, and fine motor skills through hands-on trial-and-error. Safety tips: rinse bottles thoroughly, avoid small choking hazards for toddlers, provide adult help with cutting, hot glue, or motors, use waterproof materials, and always supervise near water. Test in shallow, calm water and keep towels and a first-aid kit nearby for safe, fun experimentation.

Ready to create?