Sound Transfer

The origin of a sound wave is always an oscillating body. These oscillations can be produced by objects such as a tuning fork, drum, guitar string, bell or vocal cords. Sound propagates in the form of a longitudinal wave and requires a material medium for its transmission. For example, if we place a sound source in a bell jar with air inside, the sound can travel through the air and be heard. However, if we remove the air from the bell jar using a vacuum pump, no sound is heard once all the air is removed. This demonstrates that sound cannot travel through a vacuum — it needs particles and the bonds between them to propagate. Sound is a mechanical wave that results from the back-and-forth vibrations of the particles within the medium it travels through. If a sound wave is moving from left to right through the air, the air particles are displaced both rightward and leftward as the sound wave's energy passes through. The motion of the particles is parallel to the direction of energy transport.