Stereo Sound consists of a vacuum cleaner hose bent into a U-shape with and earpiece at each end. One visitor holds the earpieces up to his or her ears and another taps the hose with a stick. When the tap is off-center, most people have a very clear sense that the sound comes from a place to one side of the head or the other, although the sound comes to both ears. Even though the time delay is very brief, our ear-brain system can detect it. This demonstrates how we are able to locate the sources of sounds as accurately as we do.