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SOUND WAVES. A sound wave is a wave of alternating high-pressure and low-pressure regions of air. Sound Waves. How are Sounds Made?.
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SOUND WAVES
A sound wave is a wave of alternating high-pressure and low-pressure regions of air. Sound Waves
How are Sounds Made? When someone or something makes a sound, the air molecules around it vibrate, or move back and forth, and they push into the molecules in front of them. This starts a chain reaction.
Factors that Affect the Speed of Sound Speed of sound depends on: 1. Elasticity = ability to bounce back Faster if more elastic Solids are more elastic than liquids or gases so sound travels fastest through solids 2. Density For materials in the same state of matter Slower in more dense objects- particles do not move as fast because there is more matter in a given area 3. Temperature Slower in lower temperatures (sluggish) Faster in higher temperatures
Doppler Effect is the apparent change in the frequency of a sound caused by the motion of either the listener or the source of the sound. Captain Chuck Yeager
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Doppler Effect the change in the frequency of a sound caused by motion
Speed of Sound • Medium velocity m/sec air (20 C) 343 air (0 C) 331 water (25 C) 1493 sea water 1533 diamond 12000 iron 5130 copper 3560 glass 5640
Loudness= Amplitude Pitch= Frequency How high or low Measured in Hertz low frequency = low pitch, ex. rumble of a big truck high frequency = high pitch, ex. whistle or siren Fun Fact: women have higher frequencies than men. • How loud or soft • Measured in decibels (dB) • Low amplitude= soft • High amplitude= loud
Pitch= Frequency Humans can hear from 20 Hz to 20,000 Hz Ultrasound - sound waves with frequencies above the normal human range of hearing. Sounds in the range from 20-100kHz Infrasound - sounds with frequencies below the normal human range of hearing. Sounds in the 20-200 Hzrange
Resonance the frequency of sound waves exactly matches the natural frequency of an object. http://www.youtube.com/watch?v=O9FrMkhQoA4&feature=related http://www.youtube.com/watch?v=oXV45t6wlWU
How we hear a. Outer ear collects sound. b. Middle ear amplifies sound. c. Inner ear converts sound.
Musical sound a. Noise has no pattern. b. Music has a pattern and deliberate pitches. c. Sound quality describes differences of sounds that have the same pitch and loudness. d. Every instrument has its own set of overtones.