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 ...

This water rocket launcher lets you do just that. Built using the frame from an old grill, a soda bottle takes its place ... also pick up some extra PVC to make this pressurized water cannon.

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.