English: A typical garden sprayer uses an arrangement known as a "plug nozzle". The
nozzle is the cone-shaped silver coloured metal object, the
plug is the smaller piece of metal centred in the nozzle.
Water enters the sprayer from a hose connection on the bottom, just out of view. It flows up through the handle and then out of a hole centred in the nozzle, just visible in this image. The knurled plastic just behind the nozzle can be rotated, moving the entire nozzle forward or back in relation to the plug.
When the valve is opened, water flows through the hole and strikes the plug. The plug is shaped so that water striking it is deflected to the side at an angle. If the plug is positioned far from the opening, the water flows around the plug and re-forms into a stream a short distance away. If the plug is positioned close to the opening, the water is deflected into the sides of the nozzle, which deflects it forward again, resulting in a cone shaped spray.
The handle on the back of the sprayer is connected to a valve inside the nozzle, which moves backward to block the hole. A spring keeps it pressed into the "closed" position when pressure on the handle is released.
The same basic system has been proposed for a type of rocket nozzle, allowing it to adjust the exhaust stream to account for changes in atmospheric density as the rocket climbs.