A nozzle is a spout or opening at the end of a hose, pipe, or container that controls how liquid or gas comes out. The nozzle on a garden hose lets you switch between a gentle spray for delicate flowers and a powerful jet to blast mud off your bike. A fire hose has a nozzle that firefighters use to direct water exactly where they need it.

Nozzles work by changing the size or shape of the opening, which changes the speed and pattern of whatever flows through them. When you squeeze a nozzle smaller, the water shoots out faster and farther. When you open it wider, you get more water but less force. The nozzle on a gas pump clicks off automatically when your tank is full. Rocket engines have carefully designed nozzles that turn burning fuel into thrust powerful enough to escape Earth's gravity.

You'll find nozzles on spray bottles, showerheads, vacuum cleaners, and even whipped cream cans. Each one shapes the flow differently depending on the job it needs to do.