- One 2 litre plastic fizzy drink bottle
- A wine cork that fits snugly in the bottle spout
- Something that can hold the bottle, neck down, at an angle to the ground – the handle of a garden fork works well but branches, bits of wood or plant pots will all work as a launch pad
- A few litres of tap water
Top Tips for Leaders
- You might want to build a prototype and give it a go ahead of the meeting so you can get a feel for how it works and help inform your risk assessments.
- If the below instructions don’t make sense, there’s loads of YouTube videos and instructions on how to build water rockets on the internet OR you can buy ready made kits if your programme budget allows.
Check the cork will be a good tight fit in the bottle. You can wrap tape around it to make it a bit bigger.
Check the pump needle is long enough to poke through the cork and still let you attach the pump. You can shorten the cork by slicing it through if you need to.
Make a launchpad that holds the bottle with the neck downwards, lets you attach the pump and stand behind the bottle. One good method is to plant a spade or garden fork in the ground at a low angle and poke the bottle through its handle.
Into the bottle put roughly 500ml of water (a quarter of its capacity). Seal the bottle with the cork and valve. Carefully drive the pump’s needle through the cork so you can add air.
Check the launch area is clear before you start pumping. Get anyone watching to stand at least 3 metres back.
Start pumping gently and steadily, keeping the bottle lined up as best you can.
Keep pumping until the cork pops and the bottle flies away.
If the rocket doesn’t fly at all, check two things:
- Is water escaping from the bottle? Look around the cork to check if it’s sealing reasonably well.
- Is air getting into the bottle? Look for air bubbles in the water when you pump.
If the rocket does fly but not very well, there are things you can adjust.
- The amount of water makes a big difference. Start with the bottle one quarter full (500ml water in a 2l bottle) and adjust it up or down for best flying distance.
- Check that your launchpad allows the bottle to fly cleanly away. You may need to try a few methods depending on your pump and the shape of your bottle.