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Sound 1. Energy is transferred from particle to particle through matter .

Sound 1. Energy is transferred from particle to particle through matter . 2. How we hear a. Outer ear collects sound. b. Middle ear amplifies sound. c. Inner ear converts sound. 3. Properties of sound a. Intensity and loudness

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Sound 1. Energy is transferred from particle to particle through matter .

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  1. Sound 1. Energy is transferred from particle to particle through matter.

  2. 2. How we hear a. Outer ear collects sound. b. Middle ear amplifies sound. c. Inner ear converts sound.

  3. 3. Properties of sound a. Intensity and loudness 1) Intensity depends on the energy in a sound wave. 2) Loudness is human perception of intensity. 3) Loudness is measured on the decibel scale.

  4. a) Threshold of hearing (0 db) b) Threshold of pain (120 db)

  5. b. Frequency and pitch 1) High frequency means more vibrations hitting the ear. 2) Pitch is how high or how low a sound seems to be. 3) Healthy humans can hear from 20 Hz to 20,000 Hz 4) We are most sensitive from 440 Hz to 7,000 Hz.

  6. 5) Ultrasonic sound has a frequency greater than 20,000 Hz. a) Dogs (up to 35,000 Hz) b) Bats (over 100,000 Hz) c) Medical diagnosis

  7. 6) Infrasonic sound has a frequency below 20 Hz; they are felt rather than heard (earthquakes, heavy machinery).

  8. 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 Which medium does sound travel fastest? Slowest?

  9. c. Speed of sound 1) 332 m/s in air at 0 C. 2) Changes by 0.6 m/s for every Celsius degree from 0 C. 3) Subsonic – slower 4) Supersonic – faster than sound (Mach 1 = speed of sound) 5) Sonic boom (pressure cone)

  10. SONIC BOOM

  11. d. The Doppler effect – the change in pitch due to a moving wave source. 1) Objects moving toward you cause a higher pitched sound. 2) Objects moving away cause sound of lower pitch. 3) Used in radar by police and meteorologists and in astronomy.

  12. 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.

  13. Doppler Effect

  14. 4. Musical sound a. Noise has no pattern. b. Music has a pattern and deliberate pitches. Noise (B) Pure tones (C) Musical notes

  15. c. Sound quality describes differences of sounds that have the same pitch and loudness. d. Every instrument has its own set of overtones.

  16. e) Beats are pulsing variations of loudness caused by interference of sounds of slightly different frequencies.

  17. 5. Uses of sound waves a. Acoustics – the study of sound. Soft materials dampen sound; hard materials reflect it (echoes and reverberations). b. SONAR – Sound Navigation and Ranging (echolocation).

  18. Sonar Active Passive Passive

  19. Sonar Video

  20. Tsunami Wave length, 500 to 600 km in ocean

  21. Properties of Wave Video

  22. Tsunami Wave

  23. Tsunami Warning • On December 26, they were playing in the sea when Tilly suddenly found the water was bubbling, like on top of a beer. She immediately realized tsunami was coming because the scene reminded her of a geography lesson about Hawaii's 1946 tsunami. • Right away, Tilly told her parents, sister and other tourists to escape quickly, but at first they were in half belief. However, seeing Tilly's serious and firm expression, people started to be convinced of the seriousness of the thing and instantly left the beach. • At last over 100 tourists were ended up in safety with no death

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