Sound Board - Tuning Fork And Lecture Table
To demonstrate the effect of a sounding board.
If a tuning fork is struck and held in the air, it is not very loud, due to lack of good coupling between the tuning fork and the air. On the other hand, if the bottom of the tuning fork is held firmly in contact with the lecture table or other large surface, it will be much louder. The vibrations are transferred much more efficiently from the tuning fork to the table (the sounding board) and then from the table to the air.◙
R. M. Sillitto, Angular Distribution of the Acoustic Radiation from a Tuning Fork, AJP 34, 639-644, (1966). ◙Mario Iona, Sounds Around a Tuning Fork, TPT 13, 324, (1975).