1. Interactions of Sound Waves Sound Quality
Unit 13 Section 3
Sound

2. I. Reflection of Sound Waves
A reflection is the bouncing back of a wave after it hits a barrier.
A reflected sound wave is known as an echo.
Sound waves reflect best off of smooth, hard surfaces.
That’s why you can hear an echo in an empty gymnasium better than in an auditorium.

3. II. What is Echolocation?
Echolocation is the use of reflected sound waves to find objects.
Animals like dolphins, bats and birds use echolocation to hunt for food and find objects.
Echolocation helps them to tell how far away something is based on how long it takes the sound waves to echo back to their ears.

4. Echolocation

6. Echolocation animation

7. III. Echolocation Technology
Sonar is a type of electronic echolocation.
It can help:
fisherman locate fish
ship captains locate icebergs
oceanographers map the ocean floor.

8. Ultrasonography is a medical procedure that uses echoes to ‘see’ inside a patient’s body without surgery.

9. IV. What is a Sonic Boom?
When a jet flies at supersonic speeds (speeds faster than the speed of sound), it overcomes the compressed sound waves in front of it. Those sound waves crash together and spread behind the jet and create a shock wave.
A sonic boom is the explosive sound heard when a shock wave reaches your ear.

10. Video of a Sonic Boom

12. http://video. search. yahoo. com/video/play

13. Quickie Quiz
An echo is most likely to result when sound hits a surface that is:
Bumpy and soft
Smooth and soft
Smooth and hard
Bumpy and hard

14. Quickie Quiz
The use of reflected sound waves to find food or other objects is called:
Sound wave
Echolocation
Resonance
Decibel

15. Quickie Quiz
The use of sound waves to look inside the body is known as
Echolocation
Sonic booms
Ultrasonography
Fish finder

16. Quickie Quiz A sonic boom occurs because Sound waves are reflecting.
Sound waves get compressed in front of the jet and then trail off behind it.
Sound waves move from the back of the jet forward.
Sound waves are absorbing.