can air make a sound

[fondie]

heh heh heh heh

yes enery is conserved, but by transferring some form of energy to sound, surely the process by which this is caused is 'making a sound'. that's how i would view it at least. it's rather pedantic to say that a power stations doesn't 'make' electricity, it only converts one form of energy to another. a potter may only form a pot from clay of another form, rather than having conjured it from nowhere, but you would still say he had 'made' the pot (i hope?).

in those terms, it is possible for air to 'make' a sound, as wilsonian says, if two air currents collide a sound wave is created eminating from the point of impact, just as 2 cars colliding would, the principle is just the same although the density of the bodies are different. with both examples it is the transfer of energy from kinetic energy to sound (and other forms) of energy, but i would still say the cars, or the air, had made a sound.

[shiato storm]

sound cannot be carried in a vacuum - sound is the compression of air at frequencies at which our hearing can detect.
the compression waves in air actually cause the ear drum to vibrate which in turn vibrates soemthing in your ear called the cochlea to vibrate. (the cochlea is a spiraled structure that may vibrate anywhere along its length depending on the frequency of the sound - high freq at one end, low freq at the other - and thus sounds of many frequencies cause different parts to vibrate...)
therefore 'sound' is merely carried as compression waves in the medium of air, without which they cannot be carried and oscillate the eradrum to initiate the perception of sound.
to say that air 'produces sounds' is neither incorrect or correct - as air alone, just sitting there minding its own business, wont make much noise. similarly adding two airflows doesn't do much.
you 'hear' wind because of its effect on the eardrum (that sort of roaring sound you get) as it 'blasts' your ear a bit...

So I think the question you may be arguing over seems a little confused. sound is ultimately a perception - just as how one person experiences colours - and that when air 'makes a noise' it is merely the compression of the air causing pressure differences localised within the auditory canal etc. to cause hearing. so it can't really be defined as air 'making a sound' merely it causes us to percieve sound or thinking of it another way, its how we may detect a change in our environment,,,

[windog]

Aah yes but if a tree falls in a forest and there is no-one there to hear it does it make a sound?!!!!!!!

[shiato storm]

no, no one was around to exerience the perception of sound as defined in my previous post as a series of compression waves through the air. sound does not travel infinitely due to the friction and buffering effect of other air currents.

[Donny John]

/Jumps up on Desk in Homer fashion.....

AIR MAKES SOUND... AIR MAKES SOUND...AIR MAKES SOUND...

Heh

[5lab]

thunder = air making a sound

[shiato storm]

nope, sorry. thunder is the sound of static discharge in the form of lightning striking out through the air from being uilt up inside clouds, dense moist regions at altitude. the sound is the same as that as when you pull a woollen jumper off - sort of crackling sound - only very much greater as it reaches towards a 'grounding' object into which it can discharge itself. the speed at which it oves and electrifies the suffounding air molecules causes the sound to be made... but the air is not making sound again, its being used to conduct electricity and because its reasonably unconductive a sound it made as it jumps from molecule to molecule on its way to the ground - at 'lightning speeds'...air is just carrying it.

[Nick]

Um shiato, I thought that the sound of thunder was air collapsing back into the temporary vacuum created by the super heating of air by the lightning strike. When the strike is over the air stops expanding away from the strike and collapses back in, causing the thunderclap sound....

I reckon an easy way to solve this one is to ask anyone to stick their head out of a car window travelling at any reasonable speed... what's that 'rushing' noise in yer ears? Ooh, its the wind... therefore air can generate sound... nuff said...

Pub, anyone?

[Big RICHARD]

Originally posted by Elmo
you cant MAKE or DESTROY energy, it is conserved.

Now does a nuclear fission reaction work then?????

[TiG]

Originally posted by wilsonian
g/f and i had a bit of a tiff about air making sound.... god knows why it just came about! lol

my argument was that air doesn't make a sound unless put under presure (air currents, friction etc) were her argument was air carries sound not produces it.

my question is, if two diferent directioned air curents colide do they make a sound (to the human ear of other wise)?

Of all the stupid things to have an arguement about

TiG

P.S i still think Shinato Storm has got the best explaination
P.P.S - Big Richard i'm sure you'll get an answer soon enough, i could explain but i've got work to do

[spikegifted]

Originally posted by Big RICHARD
Now does a nuclear fission reaction work then?????

Nuclear fission works because the nuclei of some elements, due to extra neutrons they carry, are unstable. Upon fission, the nucleus of the original atom (which has a high level of energy used up to bound the particles together) is split into smaller atoms (which require lower levels of energy to hold the particles together). The excess energy is given out as particles (neutrons) and electro-magnetic radiation (x-rays, gamma rays, etc). The overall energy is conserved because the total energy of the system before fission (ie. neutron travelling towards the nucleus at high speed + energy bounded in unstable nucleus) is the same as the total energy of the system after fission (ie. neutrons travalling away from the fissioned nuclei + radiation + energy bounded in stable nuclei).

[spikegifted]

Originally posted by wilsonian
my argument was that air doesn't make a sound unless put under presure (air currents, friction etc) were her argument was air carries sound not produces it.

my question is, if two diferent directioned air curents colide do they make a sound (to the human ear of other wise)?

There are two different issues here that need addressing...

1) Air, while filled with gas molecules, has huge gaps between the travelling molecules, which means that although the chances of these molecules colliding with each other is quite high, I don't think they will occur at a scale large enough to produce a sound loud enough to become audiable for human ears, unless they're somehow compressed. (see next answer...)

2) It is correct to suggest that air carries sound, but that's the same for water, rails or any other materials. If you're diving in a swimming pool, you can hear someone diving into the pool because water conduct the sound to your ear drums. It is entirely possible to make sound out of air by compressing it and increasing the rate of collision - swing a tennis racket hard enough, you'd hear the sound of air or at least the sound of the racket travelling through air...

[shiato storm]

Originally posted by Deckard
I reckon an easy way to solve this one is to ask anyone to stick their head out of a car window travelling at any reasonable speed... what's that 'rushing' noise in yer ears? Ooh, its the wind... therefore air can generate sound... nuff said...

which will bring great amusement as a passing lorry smacks your head off...now, I'm sure that will make a sound but one thing I'm not so sure on is whether you will hear it or not...

in resonpse to your way of solving this question please see my earlier post explaining that it is not the air making the sound but the percieved sound that is created by the process of an increased pressure around the ears. the reason it sounds like it is roaring is that the quantity of air entering the small space that is your auditory canal cannot be contained and spills out a little, this leaves a bit of space which is then filled by air forced in again.
now think of how the ear drum will be recting during this time...in-out-in-out, though being pressed continuously it will oscillate and produce the effect of sound, though strictly speaking all it is is the vibration of your eardrum through increased pressure.

a simple test is to hold your nose and blow - you will maybe detect a change in pitch of hearing - this is because the ear drum is being distented (bulged) away from its natural position. similar to when you go diving and the increased pressure causes a 'squeese' on the ear drum until you equalise...
failure to do so may rupture your ear drums

[fondie]

Originally posted by shiato storm
sound is ultimately a perception

Originally posted by shiato storm
no, no one was around to exerience the perception of sound as defined in my previous post as a series of compression waves through the air

neither of these statements make any sense. sound is a wave, it is there whether you are there to experience it or not. do you also believe that if we all closed our eyes the sun wouldn't be shining?

the question isn't about whether/how sound propergates through air or how sound is percieved by your ear, any basic physics/biology text book will tell you that.

the question is if 2 air streams collide do they produce a sound. i think my previous post expresses my thoughts. the air molecules effectively are hitting a wall (of air molecules travelling in the opposite direction), this creates a compression wave travelling away from the point of impact (ie. a sound).

Originally posted by Deckard
Pub, anyone?

yes

[Donny John]

Originally posted by fondie





The question isn't about whether/how sound propergates through air or how sound is percieved by your ear, any basic physics/biology text book will tell you that.

Yes, the argument is: "Does air make sound?" and the answer is............YES

[Big RICHARD]

Originally posted by spikegifted
Nuclear fission works because the nuclei of some elements, due to extra neutrons they carry, are unstable. Upon fission, the nucleus of the original atom (which has a high level of energy used up to bound the particles together) is split into smaller atoms (which require lower levels of energy to hold the particles together). The excess energy is given out as particles (neutrons) and electro-magnetic radiation (x-rays, gamma rays, etc). The overall energy is conserved because the total energy of the system before fission (ie. neutron travelling towards the nucleus at high speed + energy bounded in unstable nucleus) is the same as the total energy of the system after fission (ie. neutrons travalling away from the fissioned nuclei + radiation + energy bounded in stable nuclei).

Close!

Nuclear fission is the exchange between energy and mass. The equation E=mc^2 gives the energy released when a mass, m is converted to energy. The energy holding the nucleus together is the strong force and this accounts for a very small amount of energy compared to the energy produced from the reduction in mass.

The reason I asked is because energy is effectively created from mass.