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Why does the thunder from lighting last much longer than the flash?

  1. Jun 18, 2014 #1
    I was walking home today when I noticed that the flash from a lighting takes a fraction of a second while the sound lasts a good 5-6 seconds.
    I couldn't think of an explanation for this, except a wild guess that maybe the source of sound is a line source and sound from different points on the lightning bolt takes different times to reach the observer.
  2. jcsd
  3. Jun 18, 2014 #2


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    Science Advisor

    That's most of the answer. Lightning bolts can be miles long. Sound in air needs several seconds to travel a miles-longer path. Another answer depending on your surroundings is the presence of echoes, which create additional paths.
  4. Jun 18, 2014 #3


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    Homework Helper

    Here is a video of an unusual (for southern California) thunderstorm. There are a few instances where you see the flash and hear the thunder. At this particular location, echoes from nearby hills add to the sound.

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