If your matches have tested at fewer markers than you, you will want to encourage them to upgrade to see if the match holds up. You will be able to see the Most Distant Ancestor for your matches who have provided them. Look down the list to see if any look familiar.
In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a medium such as air or water. In physiology and psychology, sound is the reception of such waves and their perception by the brain.
Sound is a kind of energy created when something vibrates. When this vibration reaches an ear, it is translated into what we recognize as a sound. Sound vibration must travel through matter. This is typically air. When you say, Hello, to a friend, the air parts (called molecules) vibrate in small waves which travel to the friend and they hear the word Hello.. Sound can also travel through other matter. Tap on the table.