echo
Definition
An echo is the repetition of sound caused by the reflection of sound waves from a surface. This can happen when sound waves hit a solid surface, such as a wall or a cliff. The sound waves bounce off of the surface and travel back to the listener.
The echo is a weaker version of the original sound, and it is delayed by a fraction of a second. The delay is caused by the time it takes for the sound waves to travel to the surface and back.
The echo is most noticeable when the sound waves are reflected from a surface that is smooth and hard. This is because smooth surfaces reflect sound waves more effectively than rough surfaces.
The echo can also be used to measure the distance to a surface. This is done by measuring the time it takes for the echo to return to the listener. The distance to the surface is equal to the speed of sound multiplied by the time delay.
The speed of sound is about 343 meters per second at sea level. This means that if you hear an echo 0.5 seconds after you shout, the surface is about 171.5 meters away.
How can the word be used?
The cave was filled with echoes.
Different forms of the word
Noun: echo, reverberation, reflection.
Verb: to echo, resound, reverberate.
Adjective: echoic.
Adverb: echoically.
Synonym: reecho, repeat, reiterate.
Antonym: silence.
Etymology
The word "echo" comes from the Greek word ēkho, which means "sound" or "reverberation". It is made up of the two Greek words ēk (sound) and o (to send forth).
Question
Where is it easy to produce an echo?
AQA Science Exam Question and Answer
Question:
Explain the phenomenon of an echo and the scientific principles behind its occurrence. Describe how sound waves are reflected and transmitted, resulting in the perception of an echo. Provide examples of situations where echoes are commonly heard and the factors that can affect the clarity and duration of an echo.
Answer:
An echo is a reflection of sound waves that occurs when sound encounters a surface and bounces back to the listener. The scientific principle behind this phenomenon lies in the behaviour of sound waves. When sound travels through the air, it consists of compressions and rarefactions, creating a pressure wave. When this wave reaches a surface, like a wall or a canyon, it gets reflected and travels back towards the source.
The time between the original sound and the echo reaching the listener is called the echo's delay. The clarity and duration of an echo depend on several factors, including the distance between the source and the reflecting surface, the shape and texture of the surface, and the absorption properties of the surrounding environment.
Examples of situations where echoes are commonly heard include shouting in a mountainous area, clapping in an empty hall, or talking in a large, open space. Understanding the principles of sound reflection and echo formation not only enhances our understanding of acoustics but also allows us to control and manipulate sound in various environments for better communication and entertainment experiences.