1. Sound
Chapter 17

2. Sound Waves Caused by vibrations of molecules.
The molecules bump each other and the sound wave transfers energy.
Remember they are a type of compressional wave, so sound has to have matter to travel through.

3. The Speed of Sound
Travel at different speeds through different mediums
Because in a ________ the particles are closer together, sound travels faster in this type of matter.
Because particles in a warm substance move _________, sound travels faster in this temperature

4. Amplitude and Loudness
Loudness: Human perception of how much energy a sound wave carries
Amplitude in compressional wave: The more compressed the compressions and the more spread out the rarefactions, the higher the amplitude.
Higher amplitude=more energy

6. The Decibel Scale
Measures the loudness of sound
Hearing loss starts occurring at 85 dB
Amount of damage depends of frequency of sound and period exposed

8. Frequency and Pitch
Pitch: how low or high it sounds
The higher the pitch, the higher the frequency
The higher the frequency, the smaller the _____________.

9. The Human Voice Vocal cords vibrate as you speak or sing.
The length and thickness of your vocal cords determine the pitch of you voice.
Short or thin vocal cords= higher frequency/higher pitch voices
Think or long vocal cords=lower frequency/lower pitch voices

11. The Doppler Effect
The change in frequency as the source of sound is moving relative to the listener.
Example: ambulance, chiming clock
Remember 6th grade science?

12. As planets move away from us, their light is shifted to lower frequencies.
What color has a lower frequency in the rainbow?
So this is called a _____ __________.
As planets move toward us, their light is shifted to higher frequencies.
What color has a higher frequency in the rainbow?
So this is called a _______ _________.

13. Music

14. Just Like Me Country? Rap? Metal? Pop? 80’s? 90’s? Alternative?
Boy Bands?

15. Music
A group of sounds that have been deliberately produced to make a regular pattern.
Created by vibrations

16. Every object will vibrate at a certain frequency
Natural Frequency
Every object will vibrate at a certain frequency
Depends on shape and size of the object, or instrument

17. Resonance
Occurs when an object is made to vibrate at its natural frequencies by absorbing energy from a sound wave or another object vibrating

18. The higher frequencies produced by a vibrating object
Overtones
The higher frequencies produced by a vibrating object

19. Stringed Instruments
Pitch of the sound depends on the length, diameter, and tension of the string
Stringed instruments usually have a hollow chamber that amplifies the sounds
Example: guitar, piano, cello

20. Percussion Instruments that are struck to make sound
Pitch depends on the length and tightness of the drumhead or bars
Example: Drums & xylophone

21. Brass and Woodwinds Instruments with pipes or tubes
Pitch depends on air column or length of pipes/tubes
Example: Flute, saxophone, clarinet, oboes

22. Reverberation
Repeated echoes of sound because of a hard surface

23. The Outer Ear
Collects sound and directs to ear canal- reason ear is shaped like a funnel

24. The Middle Ear Sound waves reach middle and vibrate the eardrum
Transmits vibrations to 3 small connected bones- hammer, anvil, and stirrup

25. The Inner Ear Fluid filled part of ear
Different sounds vibrate in different ways