3D30.20 Closed Ended and Open Ended Organ Pipes

PURPOSE: To show that an organ pipe has a higher frequency when it is open ended.

DESCRIPTION: Two organ pipes with the same size are shown in the photo at right.  One is open ended and the other is closed ended.  When they're activated by blowing carefully into the mouthpiece the open ended pipe will have a higher frequency than the closed ended pipe. 

This effect can also be shown by forcing the end of an open pipe to be closed with a stop, as shown in the photo above left, or with your hand.

References:

Neville H. Fletcher and Suszanne Thwaites, The Physics of Organ Pipes, Scientific American, 94-103,
(Jan. 1983).

Derwent M. A. Mercer, The Physics of the Organ Flue Pipe, AJP 21, 376-386, (1953).  

W.H. Barnes, The Contemporary American Organ Pipe. (1948).

EQUIPMENT:  Organ pipes, as photographed.

SETUP NOTES: None.