ok then...if a tree fell and there was no-one to hear it would it really make a sound.........?

No it would not make a sound because no one is there to hear it (that is the catch) because this is the definition of sound.

Vibrations transmitted through an elastic solid or a liquid or gas, with frequencies in the approximate range of 20 to 20,000 hertz, capable of being detected by human organs of hearing.

It would produce the waves not the sound.

Call it a noise or something other than "sound" and you are set.

The answer is NO!

Look up the word 'sound' in your dictionary.

According to my Oxford Pocket Dictionary, one definition is: "sensation caused in the ear by vibration or other medium". This definition indicates that sound is the vibration in the ear. No ear, no sound.

Another definition is "vibration that causes this sensation". Again, that indicates that if the vibration does not cause this sensation, it is not sound.

The third definition is "that which is or may be heard." Again, sound requires the sensation or potential sensation of hearing. Perhaps, the 'may be' part of it is open to some interpretation. But a literal interpretation is that if an ear is not present with a potential of hearing, then it is not sound.

(There are, of course, a number of other definitions that are not related to your question, such as transitive and intransitive verbs about making noises, the state of a person's health, bodies of water, etc.)

So, when a tree falls in the forest, do the air molecules vibrate? Indeed they do.

If there is no one there to hear it, is it sound? Not according to my Oxford Pocket Dictionary.

I just love words. Don't you...?

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edit - Just for laughs, I went to Merriam-Webster also:

"1 a: a particular auditory impression : tone b: the sensation perceived by the sense of hearing c: mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium (as air) and is the objective cause of hearing"

Without the auditory sensation, a perception of the sensation, or the objective cause of hearing, it is not sound.

BTW, it would not make a noise either. Look it up. The definition of 'noise' is 'sound'!

Yes. The sound waves would still travel through the air, even if there was no person or animal for the waves to reach.

It's simple, simple physics. It's also like saying that "If a tree fell in a forest and no one was there to see it, did it still happen?" Of course it would happen! Things don't need a witness for their occurrence.

Most certainly. A sound is a sound... and where there is a tree, there are little creatures living in it or in the near vicinity to hear the noise it would make.

Yes

It all depends how you define sound. If sound is the compression waves travelling through the air, yes it would. If sound is the sensation generated by those waves hitting the eardrum and sending signals to the brain, then no!

Yes, it makes a sound. However, does the fact that no-one exists to percieve said sound render the sound an illusion?

Yes, just because no one hears it doesn't mean it won't make a sound...it just means no one was around to hear it.

Yes.

Yes!

Same as if you didnt hear a song on the radio, the song still played.