A cylindrical and hollow metallic or wooden tube used to produce sound is called organ pipe. Organ pipe can produce sound of different harmonics by means of vibration of air particle. Musical instruments like flute, whistle and violin are some of the examples of organ pipe. To be a organ pipe:
- The body should be hollow.
- The body should have diameter less than its length.
There are two types of organ pipe in general:
1. Open organ Pipe: The organ pipe whose both ends are open is called open organ pipe. Flute is an example of open organ pipe. When air is blown through the flute (open organ pipe), wave travels through the tube from one end to another end which is then reflected back on striking the free air. When the waves collide, superposition of wave forms the stationary wave. There is one node between two antinodes in simplest mode of vibration.
2. Closed organ Pipe: The organ pipe whose one end is open is called closed organ pipe. Whistle is an example of closed organ pipe. When air is blown through one end of the whistle (closed organ pipe), wave travels through the tube from one end to another end which is then reflected to the same end from where air is blown. Due to the superposition of incident and reflected waves, stationary waves are produced. There is one antinode in between two notes in the simplest mode of vibration.