Stereo Sound consists of a vacuum cleaner hose bent into a U-shape with an earpiece at each end. One visitor holds the earpieces up to his or her ears while another visitor taps the hose with a stick. When the tap is off-center, most people have a very clear sense that the sound comes from 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.