Why does vibration always cause air to vibrate with it?

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Discussion Overview

The discussion centers around the question of why vibrating objects cause the surrounding air to vibrate as well. Participants explore the mechanisms of sound wave production and the interaction between vibrating objects and their medium, specifically air.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that when an object vibrates, it causes the surrounding air to vibrate due to direct contact and energy transfer.
  • Others argue that air can support vibrations over a broad range of frequencies, which facilitates the propagation of sound waves.
  • A participant suggests that resonance increases the efficiency of energy transfer between vibrating objects, but is not necessary for air to vibrate.
  • Another viewpoint emphasizes that the air must move with the vibrating object because it surrounds the object, similar to how fluids behave.
  • One participant notes that the phenomenon of sound wave production involves compression and rarefaction in the air caused by the vibrating object.

Areas of Agreement / Disagreement

Participants express multiple competing views on the mechanisms of air vibration and the role of resonance, indicating that the discussion remains unresolved.

Contextual Notes

Some claims depend on specific definitions of resonance and the conditions under which air vibrates, which are not fully explored in the discussion.

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When an object vibrates next to another object with the same resonant frequency it causes it to vibrate with it. Why is it that when an object vibrates, it always causes the surrounding air to vibrate with it?
 
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Air supports vibrations over a very broad range of frequencies.
 
Scheuerf said:
Why is it that when an object vibrates, it always causes the surrounding air to vibrate with it?

look close up at the vibrating object and the air that is in contact with it
as the object vibrates back and forward, what do you think is happening to that air ?

This is how sound waves are produced, say, from a loud speaker where the vibration of the speaker cone
causes compression and rarefaction pressure waves in the airDave
 
Last edited:
Scheuerf said:
When an object vibrates next to another object with the same resonant frequency it causes it to vibrate with it. Why is it that when an object vibrates, it always causes the surrounding air to vibrate with it?
If the two objects are in contact, the second vibrates even if not at resonant frequency. Even if there is some air in between the second vibrates as well. It's only that at resonance the power transfer between the objects is higher.
So your question does not really have a justification. The air vibrates because is in contact with a vibrating source. There is no need for resonance for this.
A medium like air does not have a resonance unless is restricted to some closed volume which will impose boundary conditions.
 
Scheuerf said:
Why is it that when an object vibrates, it always causes the surrounding air to vibrate with it?

The air surrounds the object, so when the object vibrates the air must move with it. The same thing happens for water or any other fluid medium. Or a solid medium if the vibrating object is in the ground.
 
Vibration can cause energy to be transferred between two objects. The special case of resonance is just the frequency at which energy transfer is at a maximum.
 

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