Yesterday I was in the waiting area while the J was doing jazz dance and I overheard some women talking.
One was helping her son with his homework and screeched, "What kind of question is this? If a tree falls in the forest and nobody is around to hear it, does it make a sound? Of course it makes a sound!" The lady across from her, who explained that she was a HS chemistry teacher, was in full agreement. I was aghast.
Such sloppy thinking. Before jumping to conclusions they should have wondered about definitions. If sound is defined as vibrations in the air, then yes, it will make sound. If sound is defined as a person having a sensation caused by vibrations in the air, then it is nonsense to say there is sound. Put it another way: If I showed you a nice fresh strawberry and asked, "What does this taste like?" You would probably say, "like a strawberry". But it only tastes like a strawberry while you are eating it, it doesn't taste like anything when it is sitting in a bowl.
There is a lot more to think about with that question such as the whole mind/body issue & etc. Really the issue is that it should be assumed that a question like the falling tree one is meant to provoke thought. To dismiss it out-of-hand is to miss the point and to show yourself a rube--to anyone who isn't--Or in my case, at least is slightly less of one.
Added: In this Family Guy episode, Peter has a vision where the trees are talking to him; so he asks them if they make a sound if they fall down and nobody is around to hear. One of them answers that Steve fell down last week and hasn't shut-up about it since. I don't remember the exact quote and that is why I didn't use quotation marks above.