This piece of engineering is so simple and elegant, you’ll want to build a pretty serious water ... the parachute and is then slipped over another bottle that makes up the body of the rocket.

It sounds really easy: you put some water in a soda bottle ... you make something vaguely rocket-shaped with fins, it’ll probably work. Then you probably need a parachute release mechanism.

Practise and challenge your friends! Download the Water bottle Rockets PDF(378 Kb). Adobe Acrobat is required. SAFETY: This rocket uses air pressure to fling a bottle at high speed 20–50 metres.