Building water rocket is a fun and easy way to demonstrate Newton's third law, In every action, there's an equal and opposite reaction. All rockets are based on this principle.

Supplies

- Cork
- play doh or clay
- Bicycle pump
- Bicycle pump valve
- Tape
- Thin stiff cardboard
- Glue
- Paper
- Soda bottle
-Slightly larger plastic water

Step 1: Make the Nosecone

Roll a piece of paper into a cone wide enough to fit on the bottom of the bottle. Feel free to use colored paper. Wrap the cone with tape so as to make it more durable and water-resistant.

Step 2: Add Ballast to the Rocket

The ballast gives weight to the rocket which makes the rocket fly straight and not tumbling round. Mold a small amount of clay not too little not too much and place it on the bottom of the bottle. Secure it in place with tape. Now tape the nose cone to the bottom of the bottle.

Step 3: Construct and Attach the Fins to the Rocket

Fins add stability to the rocket. Your fins need to be strong and durable to survive multiplelaunches. Cardboard will work for a few launches but a better material would be plastic or corriflute sheet.
• Cut 3 right-angle triangles of about 7cm high and 7.5cm wide. Reinforce the fins by wrapping them with a layer of tape. To attach the fins to the rocket, wrap a strip of paper around the bottle and then divide into three equal parts with a ruler. Transfer the markings to the bottle. This makes sure that the fins are equally spaced round the bottle. Glue the fins in place.

Step 4: Make the Launcher

Make a very small hole right through the middle of the cork just wide enough for the bicycle pump valve to fit through. Secure the valve in place with a generous amount of hot glue.
The launch pad will keep the rocket pointing up before launch. Cut out the bottom of a plastic bottle and cut a hole large enough for the bicycle pump valve adapter to pass through.

Step 5: Launch the Rocket 🚀

Make sure you are in an open area away from trees and power lines as the rocket will be traveling quite fast. Launch procedures:
• Fill the rocket about 1/3 way up with water.
• Stuff the cork tightly into the bottle's mouth.
• Position the rocket with the nose pointing upward on the launch pad.
• Pump air into the rocket. Keep pumping air as the rocket will fly off when the cork can no longer withstand the pressure building up in the bottle.

Step 6: Warning ⚠️

- Make sure that no one goes in front of the rocket while pumping as it can go off at any moment.
- Never point the rocket at anyone while or after pumping.
- If the rocket fails to launch even after vigorous pumping, do not go in front of the rocket as there is a possibility of it launching unexpectedly. Check to see there’s no leakage.