Sound Chapter 17

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. https://www.youtube.com/watch?v=JVhYuqr03IQ

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

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

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

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 _____________.

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

https://www.youtube.com/watch?v=cNSx1RdPl04 https://www.youtube.com/watch?v=eb9xuYKJVeo

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?

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 _______ _________.

Music

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

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

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

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

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

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 https://www.youtube.com/watch?v=RxFNHeXKmrY

Percussion Instruments that are struck to make sound Pitch depends on the length and tightness of the drumhead or bars Example: Drums & xylophone https://www.youtube.com/watch?v=eLiZwU0r0Lw

Brass and Woodwinds Instruments with pipes or tubes Pitch depends on air column or length of pipes/tubes Example: Flute, saxophone, clarinet, oboes https://www.youtube.com/watch?v=PjkmmTZXRjU

Reverberation Repeated echoes of sound because of a hard surface

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

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

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