Let's look a little closer a the argument (as posed by some of the above posts) that a sound is only truly a sound when it is heard. I can see where the argument comes from that a tree falling would create a pressure wave that our brain interprets as sound. However, it is unlikely there is nothing with a brain in the forest even if there are no humans around. Any animal would experience the pressure wave and interpret the sound.
This question is an example of a zen koan, a riddle used to demonstrate zen principles and/or to inspire the mind to either emptiness or a sense of universal mindedness (two things that are, in the end, the same when it comes to zen philosophy).
The point is not to answer the question but to contemplate the contradiction which functions as a symbolic representation of the "illusion of duality", the sensory limitations we are taught to live within, according to zen philosophy, and which we must escape in order to achieve a zen state.
It depends on your definition of sound. The tree falling will create what we think of as "sound waves". However the noise is created within our human body not outside. Is sound defined by someone hearing it? or the possibility that someone could hear it? That is why this has always been more of a philosophical question than a scientific one.
The tree falling would create pressure waves, which could be heard as sound by the human ear and brain. But the question says that no one hears it. So it would only be in a very limited sense that you could say it makes a sound, because those vibrations become sound in an epistemological sense only when they are converted into comprehensible signals by our brains.
First of all, I think you need to stipulate that there is no one in the forest to hear it.
Of course it does. Sound is not something that is caused by the person hearing it. It is a physical phenomenon that is caused by certain physical events. When the tree falls, it will make a noise regardless of whether anyone is there to hear it.
Yes but different trees make different sounds depending on their size for example a really thin tree would make less noise that a really bir tree. As well as this is depends on how old a tree is older trees make more noise and younger trees make less noise.... But most of this has to do with science because of all the forces the tree obtains to actually fall first and then make the noise...