If a tree falls in the forest, does it make a sound?

If a tree falls in the forest, does it make a sound? Is the philosophical thought experiment that raises questions about observation and the knowledge of reality. It is the concept that if you are in a forest with all of the other sounds around you, and a tree falls; would you even hears it? It is also worded as If a tree falls in a forest and no one is around to hear it, does it make a sound?; in other words; how do you know what happens when nobody is around?