Can Lightning Create a Sonic Boom?

[Nymn]

If two metal objects hit, do the objects have to vibrate to make a sound? Or can the air itself vibrate with the sound?

 

[Rainbow Child]

Is there was no air, could you hear the metal objects when they hit?

 

[HallsofIvy]

If the objects did not vibrate, what would cause the air to vibrate?

 

[Nymn]

I don't know. I thought sound was the result of potential energy being released as kinetic energy (I don't know much about this, bear with my ignorance :| ). So one of the metal objects would have to vibrate for there to be sound?

 

[Rainbow Child]

The sound is a wave traveling in the air. When the objects hit they beame sourses of these waves. If there is a medium for these waves to travel (i.e. the air) they will reach at your ears and you will hear the sound.

 

[russ_watters]

If the objects did not vibrate, what would cause the air to vibrate?

The collision itself will push air, creating a sound like thunder or clapping hands. The objects themselves need not vibrate.

 

[Nymn]

Oh, okay. That's what I was wondering. Someone told me that one of the objects would have to vibrate for there to be sound, but I figured the air alone would do it. A thought, is this how things like lightning make sound?

 

[Danger]

In a way. Thunder (the sound of lightning) is basically the aftermath of an explosion. A lightning bolt is in the millions of degrees, which superheats the surrounding air much as a high explosive such as C-4 would. That overpressure radiates in all directions from the path of the bolt, so the inverse square law applies to the intensity where it's heard.