Why is there a tapping sound when there is an arc of electricity?

[cfauvel]

Not a real outboard question, but we have some knoweledgable folks here so I am asking.

Is the arc creating a mini-lightening flash, and the arc is breaking the sound barrier, thus a mini-sonic boom?

or is it the sound of the air around the spark turning into plasma, thus an explosion of sorts.

 

[JB]

Re: Why is there a tapping sound when there is an arc of electricity?

The snap you hear is the shock wave generated by the arc.

 

[nwcove]

Re: Why is there a tapping sound when there is an arc of electricity?

..............mini thunder? (now that i scale things down....in whats left of my brain......it does sound like that initial "crack" of a close lightning bolt.....only tiny! lol)

 

[cfauvel]

Re: Why is there a tapping sound when there is an arc of electricity?

"mini thunder" well that's what I thought, the bolt is travelling faster than the speed of sound, thus sonic boom, but I've read elsewhere that the bolt is igniting the oxygen and hydrogen in the air, thus the conversion of air to it's forth state, plasma, is the sound of an explosion...I say the sonic boom, but want to know for sure.