Leonid Minkin - 2013-01-18
We consider the oscillations of the tines of a simple tuning fork. The power of oscillations of a tuning fork is small primary because the tuning fork tines oscillate, out of phase. As the distance between the prongs is much less than the wavelength, destructive interference is the case for all points surrounding the fork. Since the tine spacing, while small, is not zero, the interference is not completely destructive (which is why we can hear a tuning fork at all). However, sound intensity is expected to be less from the typical tuning fork with two tines, as compared to one with only a single tine. This is confirmed by blocking the wave propagation of one tine only, by placing a cardboard tube.