whistle

A whistle is a human-made acoustic device that produces a clear, sustained tone when air is forced through an opening. It consists of a chamber or tube with a mouthpiece, a windway that directs airflow against a sharp edge (the fipple), and an escape hole that creates the oscillation. The pitch is determined by the chamber size and any openings (finger holes, valves) that change the effective air column length. Whistles are built from materials including metal, plastic, wood, or ceramic, and persist through manufacture, use, and transmission across generations as a simple, reliable means of producing standardized sounds for signaling, sport, music, or warning. [formal: whistle | substrate: behavior | horizon: a moment | explicit: yes | epoch: 0.01]