If a tree falls in a forest

I've always thought it was a stupid question. I mean, duh, of course it makes a sound. So I wondered what all the brouhaha surrounding that riddle was about so I decided to wiki it.

The possibility of unperceived existence

Can something exist without being perceived? - e.g."is sound only sound if a person hears it?" The most immediate philosophical topic that the riddle introduces involves the existence of the tree (and its sound) outside of human perception. If no one is around to see, hear, touch or smell the tree, how could its existence occur? What is it to say that it exists when such an existence avoids all knowing? George Berkeley in the 18th century developed subjective idealism, a metaphysical theory to respond to these questions, coined famously as "to be is to be perceived".

and

The dissimilarity between sensation and reality

What is the difference between what something is, and how it appears? - e.g., "sound is the variation of pressure that propagates through matter as a wave"
Perhaps the most important topic the riddle offers is the division between perception of an object and how an object really is. If the tree exists outside of perception (as common sense would dictate), then it will produce sound waves. However, these sound waves will not actually sound like anything. Sound as it is mechanically understood will occur, but sound as it is understood by sensation will not occur.

Why can't we study about things like these in school. :(