What it shows
Pumped-in air pushes the water out of the nozzle downwards, and the rocket is pushed upwards (Newton’s third law). A little water (about one third of the bottle is a good start) gives far more thrust than an empty bottle.
This idea has a short entry only. For the science behind it, read the sentence above with your textbook and ask your teacher to explain the law or idea it shows, so you can describe it in your own words.
Materials
- A fizzy-drink PET bottle
- Card fins and a nose cone
- A cork or a launcher with a valve
- A bicycle pump
- Water
Safety
For this project: Launch outdoors in an open space with an adult. Wear eye protection, keep everyone at least 5 metres away, never stand over the rocket, never use a cracked bottle, and stop pumping if the bottle bulges.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
How to go about it
Numbered steps have not been written for this idea yet. Plan it with your teacher: sketch the design with measurements, build one part at a time, test each part, and write every observation with the date. The free ebooks below have step-by-step projects of the same kind.
Free ebooks for this project
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