What sort of waves are produced by tuning forks? Is it transverse, longitudinal or both? We often know tuning forks are used to to produce wave in various experiments that we do in lab. But the matter of concern is what sort of waves are produced by it? Is it transverse, longitudinal or both?
 A: Sound is a pressure wave, alternating deviations of pressure from the equilibrium. So, depending on the medium in which the pressure wave passes, you can get either type of wave (longitudinal or transverse):


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*In gases and liquids, the pressure deviations causes compressions and rarefactions, meaning these are longitudinal waves.

*In solids, the pressure deviations cause shear stresses along the perpendicular direction to the direction of motion of the wave, meaning these are transverse waves.
As far as I know, tuning forks are used in air, meaning they generate longitudinal sound waves.
A: Well, as Kyle said the sound produced by a tuning fork (or any other source) is longitudinal.
But, the tuning fork itself does both, transversal and longitudinal.
The 2 prongs are in a transversal movement (bending towards each other). But the thing is that when something bends it is doing it like a wave. So in the middle of the "U" shape of the tuning fork the two waves collide and make a standing wave which travels down through the handle.
That is why you put the handle over a surface and can hear the sound much better, because the tuning fork sends the longitudinal wave through the handle.
The most wonderful about the tuning fork is that dampening the longitudinal wave in the handle does not stop the tuning fork oscillation... 
The old egyptians had some staffs called "was scepter" that is a long metal rod (which if made in steal would have a longitudinal natural vibration of about 4~5 KHZ) and in one end of the rod they had a tuning fork, with the prongs short enough to vibrate at about 4~5 KHZ... on the other end of the rod they had other shape that it would probably vibrate at the same frequency. So they had that thing that when the tuning fork end was put to resonate, the hole thing would resonate like pushing a child on a swing... So they wonder how they cut those stones, etc etc, .. that might be a way.
