by Bryan Uber

Created on: January 24, 2011

A group of walkers come across a cave and they saw something walk inside. Intrigued they approached the opening of the cave and one walker yelled, “HELLO?” and to their surprise, all they heard was a distorted return of the walker’s voice. Many of the walkers were perplexed on what they had just experience. One walker had an understanding of what they had just experience and decided to explain to the rest of the walkers and this is what he said:

In order to understand what an echo is one must understand the properties of sound. Sound is similar to an electromagnetic wave but it is not to be confused with that spectrum of waves. The reason sound is not classified in the electromagnetic spectrum is because in order for a sound wave to travel it needs a medium to transmit the sound wave and light, X-rays, Gamma rays, and radio waves don't. A medium that enables the transmission of sound waves has to have particles. An example of a medium that contains particles is air and water. Because the sound wave needs a medium to be transmitted this applies some limitations to how sound waves are transmitted. Since a sound wave needs a medium with particles to travel, the distance in which sound can travel is limited to the density of the medium. This is why whales can communicate with each other miles apart; water is denser than air. Another property of a sound wave that is important to understand is the amplitude of the sound wave. The amplitude of a sound wave determines how “loud” the sound is. The perception of a loud sound means that the sound waves have a large amplitude. 

An echo occurs when a source emits a sound wave and this wave reflects off of a surface and returns to the point of origin. The most common demonstration of an echo could be in a gym. If an individual stands on one end of the gym and yells a syllable, the sound will travel to the walls in all directions, reflect off the walls and will eventually travel back to the individual. This feedback is defined as an echo. 

With an understanding of what an echo is, one should ask how or where are echoes used in everyday life. There are many inventions that utilize the echo, such as the radar, Doppler effect, sonar, etc. As many people know that radar is used to determine how fast an object is traveling. This technology is mainly used by police officers. The benefits of the application of an echo have proved prosperous, beneficial, and have saved lives.  

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