Sounds CoolSounds CoolExploring Sound waves

http://www.youtube.com/watch?v=_ovMh2A3P5k

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

Key TermsKey Terms

ResonanceInterference

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

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

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

Essential LearningsEssential Learnings

Carefully read and copy each of these down after we discuss them!!!!!

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

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

Essential Learnings

Sound waves may be reflected from dense forms of matter.– Sonar

http://www.youtube.com/watch?v=Z_E3zxx2l9g

– Ultrasoundhttp://www.youtube.com/watch?

v=VJKc9WE7OaM

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

Essential Learnings

Constructive interference happens when rarefactions and compressions combine to increase sound quality (working together)

Essential Learnings

Destructive interference happens when rarefactions and compressions cancel each other out (working in opposition) eliminating any sound

Essential LearningsEssential Learnings

The End!