Why do we hear an echo in a big empty room or a canyon?
Echo's Round Trip
Why do we hear an echo in a big empty room or a canyon?
Stand in the middle of a big empty room and shout "HELLO!" — and a moment later, a slightly tired copy of your voice comes back: "...hello." That returning copy is an echo. So what just happened? Your shout went on a little trip and came home.
Sound is made of tiny pushes traveling through the air. When you shout, your voice shoves the air in front of you, and that push passes from one bit of air to the next, like a whisper passed down a long line of friends. It races outward in every direction at about 343 meters per second — fast, but not instant.
