A sprinkler is a device that sprays water in a pattern, usually to water grass, gardens, or crops. The simplest sprinklers attach to a garden hose and spin or oscillate back and forth, sending arcs of water across a lawn. On hot summer days, kids love running through sprinklers, dodging the cold spray as it sweeps across the yard.

Sprinklers can be much more sophisticated than the lawn sprinklers you might play in. Farmers use massive sprinkler systems with pipes hundreds of feet long to irrigate their fields, keeping crops alive during dry weather. Some buildings have fire sprinklers in their ceilings: these specialized sprinklers detect heat from a fire and automatically spray water to put it out before firefighters even arrive.

Whether it's watering a garden, cooling off on a summer afternoon, or protecting a building from fire, sprinklers do their job by breaking water into many small droplets and spreading them over a wide area.