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Echo
At the moment when all of us are interested in nature, we want to get the correct scientific answer. In ancient times, people created legends to explain all kinds of events. The ancient Greeks came up with a very beautiful legend to explain the echo. There she is. Once upon a time I lived a beautiful nymph named Echo. She had only one drawback - it is too much to say. As punishment, the goddess Hera forbade her to speak, if it's not a conspiracy. Nymph could only repeat what she said. One day Echo saw the handsome young Narcissus and immediately fell in love with him. But Narcissus did not notice it. Nymph covered such sadness that echo vanished into thin air, leaving only your voice. And we hear her voice, which repeats everything we say. Of course, this sad legend will not be able to explain to us the nature of the echo. To get an answer, you need to remember something about the sound. Sound travels through the air at a speed of 335 m / sec. He transferred to the waves like how there are waves in the water from a pebble thrown back. Sound waves travel in all directions, like light from a light bulb. When meeting with an obstacle such as a sound wave is reflected light. At the same time, we hear the echo. Thus, echo - this reflected sound. But not all the obstacles create an echo. Some objects absorb, rather than reflect sound. That is, the sound does not return, the echo can be heard. But usually smooth flat surfaces such as walls, cliffs, overlap, creating an echo. Do you know that clouds reflect sound and create an echo? And indeed, when we hear thunder, it indicates that the sound of thunder is repeatedly reflected by the clouds. See also: Are there silent disco. The most peaceful place in the world will drive you crazy. As your voice will be heard on Venus?
Source: potomy.ru/world/493.html