Echos

An echo is like when you yell something really loud in a big empty place, like a cave or a huge room, and then you hear your voice come back to you. It's like your voice is bouncing off the walls and back to your ears.

This happens because sound waves travel through the air and bounce off surfaces. When there's a big empty space with lots of surfaces for sound to bounce off of, like a cave or a big room, the sound waves bounce around and eventually come back to your ears as an echo.

The time it takes for the echo to come back to you depends on how far away the surfaces are that the sound is bouncing off of. If it's a very big space, the echo might take a few seconds to come back to you.

People use echos to do cool things like measure how deep a well or a cave is, or to create special sound effects in movies or music. It's a fun way to play with sound!