Why do sound waves stop or disappear as they move through medium??

Question

what stops them as the move through medium?

Answer 1

If you are talking about the attenuation of sound as it travels tthrough a medium, the loss of sound is due to dispersion--the spreading out of the wave. Just like ripples in a pond, as the wave spreads out, the height decreases. You could think of it as energy conservation--as the wave travels further, and the wavefront becomes larger in space, then the size of that disturbance must shrink--as it is being spread out.

Answer 2

It depends a bit on the medium. Sound energy can be absorbed into some materials. This means the energy gets converted into heat or motion or chemical change.

http://en.wikipedia.org/wiki/Sound_proofing
Damping
Damping is the process by which sonic vibrations are converted into heat over time and distance. This can be achieved in several ways. For example, use of a material such as lead that is both heavy and soft, with the softness allowing it to damp the noise rather than allowing transmission. Making a sound wave transfer through different layers of material with different densities also assists in noise damping. This is the reason why open-celled foam is a good sound damper; the sound waves are forced to travel through multiple foam cells and their cell walls as sound travels through the foam medium. Improperly done, however, structural compliance can make things worse, enabling resonance. This process is analogous to a string holding wind-chimes: the string helps the chimes ring by isolating the vibration instead of damping it. Foam tapes may therefore be undependable in a soundproofing protocol.

Answer 3

As people have already answered, sound waves would not stop (or be destroyed) when travelling through mediums unless they come into contact with other oncoming waves of the same amplitude and frequency that could be deconstructive.

Try this test. Get a long wooden table. Sit at one end andput your ear to the table top. Have a friend, standing on the FAR end (farthest away from you) knock on the table top. You should be able to hear the knock in the table BEFORE you hear it in the air.

Certain mediums can speed up or slow down the soundwaves due to their density, as previously mentioned.

Answer 4

The only way a wave could "stop" would be by destructive interference - it hits an equal and opposite wave and is "cancelled out".
If the medium is dense, it can slow the wave down, but should not be able to stop it because of conservation of momentum.

Answer 5

the surface are and mass of the object stops the sound waves. They stop but if there was no one there to hear them how would you know if they make a sound. now thats the question you sould be asking.