What causes an echo?

Related questions

1. Is it bad to whisper?
2. Is whispering talking?
3. What is echo chamber effect definition?
4. How does echo occur?
5. What are the two applications of Echo?
6. How is echo formed?
7. Is it rude to whisper in front of someone?
8. How much is a studio booth?
9. What does an echocardiogram tell you?
10. Why do rooms echo when empty?

Tags

1. #echoes
2. #changes
3. #reflected
4. #sound
5. #original
6. #sounds
7. #smooth
8. #bounces
9. #ground
10. #bounce
11. #repeated
12. #rubber
13. #direction
14. #objects
15. #although
16. #because
17. #waves