Question

Explain why a person at a rock concert will not feel a gust of wind coming out of the speakers.

Answer 1

Hint: Sound is a wave which transfers energy and not matter. The particles of the medium is not macroscopically transferred from one location to another

Complete Step-by-Step solution:
Generally, when the speaker is emitting sounds, this means that the air around the speaker is vibrating along with the speaker at the same frequency.
Sound is essentially propagated through this means. When a source of sound vibrates, the source vibrates the sound in its vicinity, and now this vibrating atoms then vibrates the other atoms in its own vicinity, which in turn also vibrates the atom its vicinity, and so on transferring the energy from one atom to another.
A gust of wind on the other hand, is a translation of the molecules of the air from one place to another, a really macroscopic movement. When a wind is blowing, it means that the molecules themselves, due to some driving force such as pressure difference, move from a long distance from one location to another. Wind allows molecules to move several kilometres away from their original position.
Hence, we do not feel a gust of wind because the sound does not cause molecules of air to travel long distances but rather to vibrate about a mean position.

Note:
Nevertheless, the molecules of the air still move. If one places his hands very close to a speaker, he or she will feel a little breeze. However this little breeze is not felt at farther distances because of the reduction in intensity (and amplitude) of the sound.