[Phys-l] Frequency and Wavelengths

["Ricca, Bernard P" <bricca@sjfc.edu>]

Two replies in one...First:
 
>  Whith that in mind, I have read the
> various explanations of the physics of sound crossing a boundary... I urge
> others to reread these explanations from a similar viewpoint and see if
> they can't come up with more picturesque and compelling explanations.
Maybe this helps: Take a string (or twine or cord) and a thicker rope (like hemp) and tie them together. Tie one end to a wall (or hold it tightly). One can shake the other end, and if done carefully, one can see that the pulses in both media have the same frequency, but different wavelengths.
 
Second: 
> p.s. I wonder is there is an acoustical frequency doubling, etc.  
> analogous to that in optical non-linear crystals?
Yes, there are nonlinear effects in acoustical waves; in this case period doubling ("sub-harmonics") can also occur: It can be heard if one carefully bows a string using a large bow pressure.
 
Barney
 
Bernard Ricca, Ph.D.
Assistant Professor
Graduate Program in Math, Science, and Technology Education
Department of Mathematical and Computing Sciences
Saint John Fisher College
3690 East Avenue
Rochester, NY  14618
585-899-3866 (Office)
585-899-3872 (FAX)
bricca@sjfc.edu