A whistle is a simple device that produces a high-pitched sound when air is forced through it. It is commonly made of metal, plastic, or wood and is used in various contexts, such as sports, signaling, and safety. Whistles can be used to grab attention, indicate a start or stop, or communicate over long distances. In addition to its practical uses, the whistle has cultural significance in many societies. For example, referees use whistles to manage games, while lifeguards use them to alert swimmers of danger. Whistles can also serve as a tool for dog training and other forms of communication.