The Echo

An echo occurs when sound waves hit a surface, like a wall or mountain, and reflect back to the listener. This reflection causes the sound to repeat after a short delay, creating the familiar reverberation. The distance to the reflecting surface determines the time gap between the original sound and the echo; the farther the surface, the longer the delay. Echoes are more noticeable in open or mountainous areas due to fewer absorbing surfaces. They help in navigation and can be used in technology, such as sonar, where sound reflections detect objects underwater.