ChatterBank2 mins ago
No best answer has yet been selected by fwbb. Once a best answer has been selected, it will be shown here.For more on marking an answer as the "Best Answer", please visit our FAQ.
incitatus is almost right. It is not the particles that vibrate though. Sound is propigated by a pressure wave, air (for eg). Consider a speaker, the diaphram moves in and out, this compressed the air in pulses. The distance between these is the wavelength. How quickly the sound can travel then depends on how quickly the pressure wave can propigate. This depends on the air pressure.