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When you're driving and you open 1 car window, say the front one, there comes a horrible noise, but when you open another window just the slightest bit, this noise goes away (I'm sure most people know what I'm talking about then I mention this 'noise').

  1. Why does this noise occur?
  2. Why does it go away when another window is slightly opened?

(Not sure about the tag).

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1 Answer 1

up vote 11 down vote accepted

The car is behaving like a closed pipe, so you get a resonance set up. There's a Wikipedia article here, but for once the Wikipedia article isn't that great, so there's another better article here. I imagine you (like most of us) will at some point have discovered you can make a sound by blowing across the top of an opened bottle, and it's the same thing happening in your car with the open window acting like the opening in the bottle. Since your car is much bigger than a bottle the resonance frequency is uncomfortably low.

When you open a second window you get an air current flowing through the car and this destroys the resonance.

Later: amazingly someone has actually published a paper about this. See http://www.me.iitb.ac.in/~fmfp/FMFP%20PROC/am_13.pdf. Some people have too much free time :-)

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Finally I know. Someone published a paper, do scientists get paid for publishing papers? –  Olly Price May 22 '12 at 15:33
4  
@OllyPrice - no we just do it for the fame,glory and women –  Martin Beckett May 22 '12 at 15:42
    
Perfectly good reasons if you ask me –  Olly Price May 22 '12 at 15:43
    
Check this out google.com/search?q=why+do+scientists+publish+papers –  raindrop Dec 23 '12 at 6:51

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