Physics buffs: Is this Wiki Answer re: sound waves perturbed by wind true?

[Mike 03]

Q: Can wind affect sound waves?

ANSWER:

Yes
Yes, wind can blow and distort sound waves. This is apparent sometimes when listening to open-air concerts close to the sound stage and far from it. Wind currents and atmospheric phenomena can alter or distort the sound waves, which travel through air (some medium is required) by compressing and decompressing the air molecules. Winds and other air currents can perturb that action and distort the sound, either by altering its amplitude, changing its apparent direction, or even altering its frequency slightly.

***

I was going to post this question here but figured there had to be someone else on the web who has asked this question before, perhaps millions of people. To my surprise only a couple of hits came up on the search engine.

I was sure I was going to get blasted for asking such a stupid question when I was sure that the answer was most likely "No."

:rofl:

My reasoning in thinking the answer was "No" was that sound "seemed" distorted because the impact of the wind waves against my eardrums were creating the illusion that soundwaves had been distorted. I imagined sound waves to be a bit like other oscillating waves, like those emited from a TV tube, that extend from the locus of emission without being disturbed by other environmental factors.

So there ya go. Learn something every day.

This stuff fascinates me. Just want to survey the science-minded DUers here to make sure the Wiki answer is accurate. It is the only "answer" anyone gave and there are no comments as to its accuracy.

[Solon]

1. Well, the thing is, of course, that sound only travels through mediums that can be vibrated by it...

Hence, in extremely low, or no atmosphere(a vacuum), sound cannot be produced. As such, things such as low or high pressures systems in the air, which causes wind, can distort sound in various ways. It also affect how far a sound can be heard. Another example would be in water, because water is so much denser than air, sound can travel much farther and faster than it does in air.

Remember, the definition of the "speed of sound"(Mach) as applied to Aircraft only applies at 1 atmospheric pressure or so.

[Mike 03]

4. Yes, this makes sense. That is why I can stand in my office listening to my

neighbors speak, and when it's windy it's harder to hear what they are saying?

[rug]

2. I am usually perturbed when I hear the sound of someone passing wind.

[Orsino]

3. Yes. Just as gravity wells distort light rays.

Sound waves won't pass through a vacuum, as we know, but what may not be so obvious is that variations in air density can also refract and reflect them.

http://www.britannica.com/EBchecked/topic/555255/sound/63980/Refraction
Refraction is also observable on windy days. Wind, moving faster at greater heights, causes a change in the effective speed of sound with distance above ground. When one speaks with the wind, the sound wave is refracted back down to the ground, and one’s voice is able to “carry” farther than on a still day. When one speaks into the wind, however, the sound wave is refracted upward, away from the ground, and the voice is “lost.”

[Mike 03]

5. Duh, that's an excellent point. I can't believe I didn't think of that.

Yes, gravity distorts light waves, absolutely. At the time I was thinking about sound, I couldn't think of an example of light being perturbed, but obviously, yes... the famous "Einstein Cross" or whatever it's called, where the same star (or is it a binary star system?) appears as a double of itself because of a heavy body (neutron star?)

Thank you for reminding me of this.

[Orsino]

8. A balloon filled with carbon dioxide can act as a sound lens.

It's a very cool effect, which I used to get across the concept of gravitational lensing to my astronomy students (as well as the obvious optics lesson for physics class).

[Mike 03]

6. Problem solved. Thank you! That is why I love this place. NT

[HiFructosePronSyrup]

7. Ever drive on the freeway with your windows down?

Hard to follow a conversation, isn't it?