Two ears located on either side of the head allows us to locate the source of a sound. Try closing your eyes and have someone clap his hands. You will be able to point at that person because your brain is able to compute how much time went by between when your left ear heard the sound and when your right ear heard the sound. This can work because sound moves through air pretty slowly. It reaches one ear before the other, and your amazing brain can use that information to help you locate the sound!!!
