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Question

What causes an Echo?

Answer 1

an echo is sound waves bouncing off an object

similar to the way light bounces off a mirror

Answer 2

An echo is reflected sound waves.

Answer 3

An echo is caused when a surface is smooth and hard enough  to reflect sound back to you. Even water can do it. The farther away the object reflecting the sound the longer the delay before the echo.

If the sound is reflected off multiple surfaces you'll get multiple echoes. If the sound is reflected back as the voice of God, you'll get on Oprah.

Answer 4

the sound waves that come out of your mouth hit the walls of the room or cave or whatever, and bounce back and you hear them again (and again, and again)

Answer 5

they come from open space and sound waves

Answer 6

open space. for example an empty room, it bounces off the walls. well i think. I could be wrong.