1. Sounds CoolSounds Cool
Exploring Sound waves
http://www.youtube.com/watch?
v=_ovMh2A3P5k

2. Key Objectives:Key Objectives:
The student will investigate and
understand the interactions of sound
waves
– Comprehend that resonance causes a
second object to vibrate at the same
frequency
– Recognize everyday examples of sound
waves that demonstrate constructive and
destructive interference

3. Key TermsKey Terms
Resonance
Interference

4. Resonance
When sound waves travel in phase
– Can result in other objects
vibrating at the same frequency
– Glass vibrating and then
breaking when a soprano sings

5. Interference
The combination of two
or more waves that
results in a change in
sound quality
If it improves sound
quality, it is called
positive interference

6. Interference
The combination of two
or more waves that
results in a change in
sound quality
If it lessens sound
quality it is called
destructive interference

7. Essential LearningsEssential Learnings
Carefully read and copy each
of these down after we discuss
them!!!!!

8. Essential LearningsEssential Learnings
All sound travels in longitudinal
waves with a clear discernible and
graphable pattern of compressions
and rarefactions
http://www.youtube.com/watch?
v=27a26e2CnuM

9. Essential LearningsEssential Learnings
The speed of sound through a
material depends on the type of
material
– More dense the material (solid),
the faster sound waves travel
– Less dense the material (gas),
the slower the waves travel

10. Essential Learnings
Sound waves may be reflected
from dense forms of matter.
– Sonar
http://www.youtube.com/watch?
v=Z_E3zxx2l9g
– Ultrasound
http://www.youtube.com/watch?
v=VJKc9WE7OaM

11. Essential Learnings
When sound travels in phase, it is
called resonance.
– If it improves the sound quality it is
called constructive interference
– If it decreases sound quality it is
destructive interference

12. Essential Learnings
Constructive interference happens
when rarefactions and
compressions combine to increase
sound quality (working together)

13. Essential Learnings
Destructive interference happens
when rarefactions and
compressions cancel each other
out (working in opposition)
eliminating any sound

14. Essential LearningsEssential Learnings
The End!
