The concept of echo must be familiar to most of us. While standing in an empty space, if you let out a loud shout, you can hear a faint sound coming back after a few seconds. This reflected wave of sound that resembles the original is called the echo. It can be experienced when you are standing on top of mountains, in remote places, in big and empty rooms, in caves etc.
The term echo is derived from the Greek word meaning sound. There are many factors influencing the creation of echoes. Typically, the sound waves can bounce off only if the objects they hit are smooth and hard. It is like a rubber ball bouncing off the ground. If the waves meet a soft surface, for example a cushion, they will be absorbed, and hence, no echo will be created.
There are multiple uses for echoes. They can be used to measure distance, velocity, and the shape of objects. It is to be noted that an improper arrangement of echoes will result in unclear sounds.