Echoes are fun to explore. Most individuals remember their first experience in a building or outdoor area that reflected their voice back to them. For kids this is an amazing new discovery. With discovery comes questions, however. After a while most people really start to wonder how things work, and echoes are no exception. We know they happen, but how? Sound is a complex phenomenon and reacts differently depending on the surroundings.
The Greek word “echos” means “sound”. There is an ancient Greek folk tale that involves a nymph named Echo. She had undergone a curse that only enabled her to speak the last words spoken to her. This mountain nymph is a physical representation of how these sounds work.
The basic explanation for an echo involves the act of reflection. The sound simply has nowhere to go in some instances. If you yell into a well, for instance, those sound waves hit the walls, or the water, and come back to you. Of course, the time frame for the return is very different depending on the area. An echo from a large canyon takes much more time to return than the one from the small well. The time frame it takes for sound to return is used for some interesting distance calculations.
Calculations are used to find out the location of certain items. For humans, this may be a tactic used in the ocean while exploring a shipwreck, for example. When looking for items underground, echolocation can also be helpful. The ocean and underground are two places where it can be difficult to see. Scientists may want to determine how far a certain layer of the earth is, but cannot physically see through the ground. The ocean is also very dark at extreme depths. Calculations are made by understanding the speed of sound and using formulas to determine distance. The time it takes for an echo to return, is put into the formula with the speed of sound. This gives the distance of the item. Thankfully, humans do not need this skill for food or other survival needs, as this takes much longer than it does for animals.
Many animals use their ability to echo sounds for necessary functions. In the deep parts of the ocean, visibility is limited. Many sea animals used echoes to find their way around and “see” what is around them. Dolphins and whales are two such sea creatures. When animals use echoes to determine their surroundings, it is called echolocation or sonar. Dolphins send out clicking sounds at high frequencies and wait to receive the feedback. The returning sounds are gathered by their forehead and jaw. The fatty tissues in these spaces take in the sound and deliver it to their ears, which pass the information on to the brain. The dolphin can then learn about the environment. This process seems lengthy, however, it takes place in seconds.
Bats are land animals that also use echoes to navigate their surroundings. Bats are nocturnal and need this extra ability to explore their surroundings. They also spend a large part of their time in caves, which are perfect for echo experiences. Bats send out ultrasonic sounds from their mouth or nose. Bats are able to locate items as tiny as mosquitos by using echolocation. While humans cannot hear these sounds, many insects can. Moths often try to avoid becoming a meal when they hear the sounds of the bats. They try to defend themselves by escaping the area or flying in random patterns to confuse the predator.
Echo play is often a fun activity to do when out on a hike or while in a cave. This activity may not have a huge impact on how humans find food or navigate, however, it is very important to the survival of many animals. Humans use echolocation machinery to find things underwater, and underground. It is extremely helpful for scientists in research situations. Sound waves are an important part of looking around where eyes cannot see.