Download the Water ... bottle? Look for air bubbles in the water when you pump. If no, make sure the valve can open to let air through from the pump. It may be damaged or screwed shut. If the ...

Water gets pushed down, bottle flies up. Done? Oh no! The first step into more sophistication is the aerodynamics. But honestly, if you make something vaguely rocket-shaped with fins, it’ll ...

The problem with a lot of these water bottle rocket projects is that they leak where the bottle meets the launcher. In most cases this is a good thing as it’s almost impossible to build up ...

When the rocket is released from the launcher, the high pressure inside the bottle equalizes with the air outside, pushing the water out through the hole in the bottom, propelling it forward.