Echo By Eliana Muah by alma muah https://padlet.com/almamuah/37d5o5mgu2y8 en-us 2017-01-26 03:28:38 UTC 2017-05-17 07:34:10 UTC hello@padlet.com When moving sound waves hits a surface, the energy bounces off back at us. That is called an echo. almamuah https://padlet.com/almamuah/37d5o5mgu2y8/wish/149502153 2017-01-26 03:29:05 UTC https://padlet.com/almamuah/37d5o5mgu2y8/wish/149502153