Re: [Audacity-nyquist] Lightning, was Re: Echo Location

[paul b. <sni...@fa...>]

Yes indeed, we have our hands full. I don't own a gun, but apparently,
certain, high velocity shots start with a SHOCK wave. For sure, a
lightning crack starts with a shock wave, even though, there is no
moving object. 

-PB

On Thu, 04 Oct 2007 17:35:17 -0400, "Roger Dannenberg" <rb...@cs...>
said:
> The rumbles that follow a lightning crack are reflections of the sound, 
> largely from clouds. The clouds are very diffuse and very large, so they 
> act as low-pass filters (one could probably explain this in various 
> ways). The distances involved provide long delays, whereas the initial 
> crack is the sound of the lightning coming directly to you. The sound 
> itself is from the rapid expansion of the super-heated air. I believe 
> that if lightning extends over a time of perhaps a few seconds with many 
> branches that the timing and varying distances of the branches will lead 
> to more than a single crack, and I recall some interesting lightnings 
> sounds with more of a crackling of high frequency pops and their 
> evolution. However, since a complex sound could also arise from 
> reflections off of buildings, I can't be sure how those complex sounds 
> came about.
> 
> 
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-- 
  paul beach
  sni...@fa...