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Author Topic: Why are there different sound types of thunder?  (Read 21389 times)

Joseph Reninger

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Why are there different sound types of thunder?
« on: 28/04/2009 22:30:04 »
Joseph Reninger  asked the Naked Scientists:
   
Love the show!

I currently have a thunderstorm going on where I live and some of the thunder sounds like one loud bang or clap and other thunder sounds like a long rolling sound like a bowling ball going down an alley. What causes the difference?

Thanks!

Joseph R. from Columbia, Maryland, USA

What do you think?

stereologist

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Why are there different sound types of thunder?
« Reply #1 on: 29/04/2009 00:54:46 »
The difference is due to the way in which the lightning jumps from one spot to another. A vertical lightning strike from cloud to earth arrives at the ear as a bang. A cloud to cloud strike can sound like rolling thunder because the bang you hear comes along the length of the bolt.

Sound moves at about 300 meters a second or about 1000 feet a second. That's fairly rough, but gives you an idea of the speed. If a lightning bolt is quite long across the clouds, say 1500 meters, then you hear the bang over 1500/300 = 5 seconds. That's the rumble you hear.

paul.fr

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Why are there different sound types of thunder?
« Reply #2 on: 29/04/2009 23:41:32 »
The reason thunder rumbles is due in part to two things. The first being, a lightning bolt is very rarely a straight line and is never equally distant from you at all points. A lightning bolt on average is 4 miles long, it zig-zags all over the place, and can have many limbs that branch out in many different directions separated by many miles. As a result, the compression waves created by each part of the lightning bolt reach you at different times. The sound wave that has traveled a greater distance will be softer and arrive later than a compression wave created by a part of the lightning bolt that was closer to you. The second thing is the compression waves (or the thunder) will bounce around and off the clouds, the ground, and other objects nearby. Much like your voice echoes in a canyon or large auditorium, so do the compression waves generated by lightning. These two things will cause some compressions waves to arrive at the same time which is why the thunder might get loud, then soften a bit, then get loud again (the rumbling we hear). If you have had a lightning bolt crash down really close to you, the thunder doesnít rumble as much and sounds more like an explosion. Thatís because the compression waves didnít have a chance to bounce off many things before you heard it. Whereas if you were further away, you would of heard the rumbling.

http://www.weatherimagery.com/blog/facts-about-thunder/

stereologist

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Why are there different sound types of thunder?
« Reply #3 on: 01/05/2009 03:17:11 »
I wish I had that as well as you did.

peppercorn

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Why are there different sound types of thunder?
« Reply #4 on: 28/06/2011 14:01:04 »
Ha !
Was just wondering why thunder (as it did here just now) sometimes emanates as a long rumble followed by *BANG!*

So I thought I would 'search' my fav. science-based forum place...
And here (almost) is the answer on a plate!

...
Still seems odd that if it's sound of one far away bolt bouncing around and interfering with itself :o it can make a  *rumble rumble rumble rumble BANG* sound... hmmm?

imatfaal

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Why are there different sound types of thunder?
« Reply #5 on: 28/06/2011 14:33:45 »
Hi PepperC - does thunder sound different depending on the direction?  Cos I heard the thunder an hour or so ago, from SW1, and just got a long low rumble. 

peppercorn

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Why are there different sound types of thunder?
« Reply #6 on: 29/06/2011 17:02:01 »
Hi PepperC - does thunder sound different depending on the direction?  Cos I heard the thunder an hour or so ago, from SW1, and just got a long low rumble.

I reckon the rumble you were hearing in SW1 was part of the same storm front I heard half an hour earlier in SE23! ;D

Why the long rumble followed by a bang though  - I don;t know!?

imatfaal

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Why are there different sound types of thunder?
« Reply #7 on: 29/06/2011 17:14:32 »
An echo off denmark hill?  i am looking at places in se22 and that damned hill worries me as I want to cycle to work and first thing in the morning I reckon it will be hard going!

peppercorn

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Why are there different sound types of thunder?
« Reply #8 on: 30/06/2011 09:16:45 »
An echo off denmark hill?  i am looking at places in se22 and that damned hill worries me as I want to cycle to work and first thing in the morning I reckon it will be hard going!

The London cycle maps are pretty useful - I do quite a bit of cycling (or did till my back wheel fell apart at the weekend! grrrr!)  Good luck with your house hunt :)

Ahum! .. I think I hear the 'topic police' approacheth...
Er , as I was saying, the reflective compounding effective of compressive waves follows the inverse square law of ... few I think they've gone past now :D

Michael J. McFadden

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Re: Why are there different sound types of thunder?
« Reply #9 on: 07/05/2012 14:30:58 »
I'd like to share a memorable and unique thunder experience I had roughly 30 years ago.   I was lying down and just barely drifting into sleep in an attic with large windows about a block away from the Atlantic Ocean on the Jersey shore.  It was a summer night, late, no storm activity that I was aware of, either before or after.

I was lying there with my eyes closed, not quite asleep, when there was an absolutely blinding flash that came right through my closed eyelids and simultaneously (as far as I could tell) an IMMENSE crack of thunder ... which then, over a period of five to ten seconds "rolled" off into the distance with slight, seemingly wave form, undulations.

I was up and on my feet within a second or so of the flash, listening to the receding thunder and trying to put together in my head what just happened.  I imagine that a significant bolt of lightning must have come "out of nowhere" (so to speak) and hit a lightning rod on top of one of the cupolas of the house and that I was then listening to echoes of the thunder bouncing back to me as the sound wave moved outward.   My adrenaline level was so high it took me over an hour to calm down and get back to sleep (after wandering around looking out all the windows for either evidence of damage or other storm activity.)  I was so spooked I was wondering for a bit if I'd gotten hit and was actually dead!  LOL!

Heh...  glad I hadn't picked that night to sit out on the roof and do any stargazing!

  :)
MJM

 

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