LinuxMusicians

I was thinking how audio waves go through air and move their molecules to generate sound and the way our ear receives the signal.

But, using a piano as example, if we take a piano in outta space and start playing it, is it audible?? Dose it generate audio waves??? Or is the impact completely mute?

thanks.

space is "nothing". so, no way soundwaves can be transmitted.

crazy, even violin as well? no matter how hard the strings are played??

Sound waves are compression waves in a physical medium (air, water, wood, etc). If there is no physical medium, i.e. the vacuum of space, there is no way to transmit the sound.

also a string wouldn't stop to vibrate unless you force it to. (or am I thinking wrong?)

There's a neat experiment that nicely shows that when you remove the air from a stolp under which a bell is ringing, you stop hearing the sound (because it has nothing to travel though anymore):

https://www.youtube.com/watch?v=ce7AMJdq0Gw

It's even more convincing when you see/hear it in real life, of course.

Capoeira wrote:also a string wouldn't stop to vibrate unless you force it to. (or am I thinking wrong?)

It would probably stop because of the tension within the string. At least that's what I think. It's not the air that stops the string, eventually.

karm wrote:

Capoeira wrote:also a string wouldn't stop to vibrate unless you force it to. (or am I thinking wrong?)

It would probably stop because of the tension within the string. At least that's what I think. It's not the air that stops the string, eventually.

ooooh yea. you are right

HILARIOUS VID!!!

That's crazy, so ALL sound depends on air molecules?? so weird.

But what happens to the impact? If the sound waves are result of excess force, where does that excess force go to if there isn't any air?? The atoms still get the shaking from the hammer note.

A string will vibrate until is dissipates all of its vibrational energy. In air energy will be lost producing sound waves and also by stretching and heating the string and transfer of energy to the support structure holding the string. In space, a string would vibrate for a lot longer since energy is not lost to sound waves.

varpa wrote:A string will vibrate until is dissipates all of its vibrational energy. In air energy will be lost producing sound waves and also by stretching and heating the string and transfer of energy to the support structure holding the string. In space, a string would vibrate for a lot longer since energy is not lost to sound waves.

Intuitively I'd say the energy needed to actually get the air molecules to wobble should be tiny compared to other losses (friction etc), and so there should be fairly little difference in how long a string keeps vibrating in space. But I'm not sure how to test that intuition.

[quote="raboof"Intuitively I'd say (..) there should be fairly little difference in how long a string keeps vibrating in space.[/quote]
I guess it's noticable - http://www.usc.edu/CSSF/History/2009/Projects/J1917.pdf

raboof wrote:Intuitively I'd say the energy needed to actually get the air molecules to wobble should be tiny compared to other losses (friction etc), and so there should be fairly little difference in how long a string keeps vibrating in space. But I'm not sure how to test that intuition.

Play the violin in front of the beach in a nice morning. Then go into the water up where the water reaches your neck, the play the violin again and see how long the strings last vibrating.

A simpler analogy would be waving your arms in the air, then wave them under water. There's a noticeable difference in friction.

If you were playing a piano in a vacuum then the vibrations would still travel through whatever it was standing on. If you put your space helmet against the piano you would be able to hear it as it made the air in your helmet vibrate. If you taped a microphone to the piano you could record it. Sound is vibration, not necessarily through air (or liquid).