Sound waves affected by wind/sound waves in materials

In summary, sound waves can be affected by wind and their speed is dependent on the medium they are traveling through. When a medium is moving, that motion is added to the motion of the sound. The speed of sound in brass is much higher than in air. When a bell is struck, the sound is transferred to the air and then to the listener's ear. When striking train tracks, the sound travels through the rails and is also spread to the nearby air. When the sound is close to the listener, it is heard through the air. However, the sound travels better along the rail than in air, so the listener may need to be closer to the rail to hear it.
  • #1
aspodkfpo
148
5
Homework Statement
Are sound waves affected by wind?
Sound waves in materials, listen by ear?
Relevant Equations
n/a
Are sound waves in air affected by wind? If the medium of the air propagation travels forward, does the sound also travel faster or is the sound simply vibrations in positions of space which disregard the movement of its medium.
Would a transverse wave similarly move faster?

If I was to attempt to record the speed of a wave (e.g. smashing the metal with a hammer) traveling in a metal over a distance of 1km. Would I have to press my ear against the metal to hear it, or would I hear it while standing as well?
If I stand would I hear both the wave in air and the metal, or only the air?
 
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  • #2
Sound waves are affected by wind.
The speed of sound is a speed within the media (air).
So if the media is moving, that motion vector is added to the motion vector of the sound.

The speed of sound through brass will be 6 to 16 times as high as it is in air - depending on the grain of the brass.

It you strike a bell, you are hearing sound in the bell transferred to the air and then to your ear.
 
Last edited:
  • #3
.Scott said:
Sound waves are affected by wind.
The speed of sound is a speed within the media (air).
So if the media is moving, that motion vector is added to the motion vector of the sound.

The speed of sound through brass will be 6 to 16 times as high as it is in air - depending on the grain of the brass.

It you strike a bell, you are hearing sound in the bell transferred to the air and then to your ear.
If I strike the train tracks, and put my ear against it, do I hear the speed of transmission through the material?
 
  • #4
.Scott said:
It you strike a bell, you are hearing sound in the bell transferred to the air and then to your ear.
Yes, but in the scenario in this thread you have the option of also hearing sound which has covered most of the distance by rail. That will arrive at a different time.
(I'm assuming @aspodkfpo means that you are listening next to the rail some distance from where it was struck.)
 
  • #5
haruspex said:
Yes, but in the scenario in this thread you have the option of also hearing sound which has covered most of the distance by rail. That will arrive at a different time.
(I'm assuming @aspodkfpo means that you are listening next to the rail some distance from where it was struck.)

So the sound travels through the rails while also spreading to nearby air, and when it is close to you, you hear the sound via air?
 
  • #6
aspodkfpo said:
So the sound travels through the rails while also spreading to nearby air, and when it is close to you, you hear the sound via air?
When what is close to you, the original impact or the rail?
The sound will travel better along the rail than in air, partly because it is not getting spread out over a sphere. By the same token, it doesn't travel well from the rail into the air, so you can be a long way from the impact by rail, but then need to be close to the rail to hear it.
 
  • #7
haruspex said:
When what is close to you, the original impact or the rail?
The sound will travel better along the rail than in air, partly because it is not getting spread out over a sphere. By the same token, it doesn't travel well from the rail into the air, so you can be a long way from the impact by rail, but then need to be close to the rail to hear it.
when the rail is close
 
  • #8
aspodkfpo said:
when the rail is close
Ok
 
  • #9
haruspex said:
Ok
so I am right about that?
 
  • #10
aspodkfpo said:
so I am right about that?
Unless you lay your head on the rail you can only hear the sound by air as the last hop. And the sound always starts in the rail, so there are always the two stages.
If you are close to where the rail is hit, there's a lot of sound energy in the rail, so despite the hurdle of transferring it to air you hear it well. But it doesn't carry as well in air as it does along the rail, so you can be a long way from the strike point as long as you are close to the rail.
 
  • #11
haruspex said:
Unless you lay your head on the rail you can only hear the sound by air as the last hop. And the sound always starts in the rail, so there are always the two stages.
If you are close to where the rail is hit, there's a lot of sound energy in the rail, so despite the hurdle of transferring it to air you hear it well. But it doesn't carry as well in air as it does along the rail, so you can be a long way from the strike point as long as you are close to the rail.

So I suppose laying your head on the rail is much more accurate for trying to experiment for the speed of a sound through the rail?

Why is there a hurdle of transferring it to air? Doesn't the rail just vibrate, and the surrounding air particles vibrate around it?
 
  • #12
aspodkfpo said:
So I suppose laying your head on the rail is much more accurate for trying to experiment for the speed of a sound through the rail?

Why is there a hurdle of transferring it to air? Doesn't the rail just vibrate, and the surrounding air particles vibrate around it?
Change of medium is always a bit of a barrier for a wave, including light. The bigger the change, the greater the barrier.
Consider a wave front radiating out from the centre of a solid cylinder (rail) and reaching the outer surface. Most of the energy will be reflected back in, and only a small proportion transferred to the air. That's why the rail continues to ring, and why the sound can go a long way along the rail with only modest attenuation.
 
  • #13
haruspex said:
Change of medium is always a bit of a barrier for a wave, including light. The bigger the change, the greater the barrier.
Consider a wave front radiating out from the centre of a solid cylinder (rail) and reaching the outer surface. Most of the energy will be reflected back in, and only a small proportion transferred to the air. That's why the rail continues to ring, and why the sound can go a long way along the rail with only modest attenuation.

How is most energy reflected? is there some boundary, what causes this boundary?
 

1. How does wind affect sound waves?

Wind can affect sound waves in a few different ways. First, wind can cause sound to be distorted or muffled as it passes through the air. This is because wind creates turbulence and changes the density of the air, which can cause sound waves to bend or scatter. Additionally, wind can also affect the speed of sound, making it travel faster or slower depending on the direction and strength of the wind.

2. Can sound waves travel through different materials?

Yes, sound waves can travel through different materials, but they may be affected by the properties of the material. For example, sound waves travel faster through denser materials like solids compared to less dense materials like gases. Sound waves may also be absorbed or reflected by different materials, which can change the way they travel and how they are perceived by our ears.

3. How does the temperature of a material affect sound waves?

The temperature of a material can affect sound waves in a few ways. First, temperature can affect the speed of sound, with higher temperatures causing sound waves to travel faster. Additionally, temperature can also affect the density of a material, which can impact how sound waves are transmitted through it. For example, colder temperatures can cause a material to become more rigid and dense, which can affect the way sound waves travel through it.

4. Can sound waves be blocked by certain materials?

Yes, sound waves can be blocked by certain materials. Materials that are dense and have a high absorption coefficient, such as thick walls or soundproofing materials, can block or reduce the transmission of sound waves. Additionally, materials that reflect sound waves, like smooth and hard surfaces, can also block or redirect sound waves away from a certain area.

5. How does the direction of wind affect sound waves?

The direction of wind can affect sound waves in a few different ways. First, wind blowing towards a sound source can increase the loudness of the sound by pushing the sound waves towards the listener. On the other hand, wind blowing away from a sound source can decrease the loudness of the sound by pushing the sound waves away from the listener. Additionally, wind blowing perpendicular to a sound source can also cause sound waves to bend and change direction, which can impact the way we hear the sound.

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