2. 1 Sound waves travel through a medium and can be visualized by Longitudinal or Compressional waves. As the sound moves through the medium, the particles vibrate against one another causing the compressions: Sound A slinky is a good example of how longitudinal waves behave.

3. 2 Rarefaction Compression Wavelength

4. 3 What is Sound? A sound wave is a pressure wave with regions of high (compressions) and low pressure (rarefactions) initiated by a vibrating object. Combination of inertia and restoring force produces harmonic motion and waves Harmonic motion is an oscillation in pressure and the wave is sound wave

5. 4 1. Medium (solid, liquid or gas) 2. Temperature

6. 5

7. 6 Sound requires contact. So which of the above would be a better medium? SolidLiquid Gas Sound does NOT travel in space – there is no air to carry the sound (vacuum) 1525 m/s 3350 m/s 343 m/s

8. 7 Temperature Do molecules move faster or slower as temperature increases? So would sound travel faster or slower as temperature increases? 343 m/s 20°322 m/s 0°

9. 8 All waves have 3 things in common. 1.Frequency 2.Pitch 3.Intensity / Amplitude

10. 9...the number of wave crests that pass one place each second. Frequency is measured in Hertz Frequency and wavelength of sound are inversely related – when frequency goes up the wavelength goes down proportionally A. B.

11. 10 Doppler Effect The sound changes to a higher frequency when the source comes towards you......and to lower frequency when it moves away

12. 11 Depends on the frequency Lower note / Lower frequency Higher note / Higher frequency White noise – equal mix of all frequencies

13. 12 Which wave do you think has more intensity? Intensity is defined as the amount of energy (or amplitude) a wave has... The greater intensity, the louder the sound will be. A. B.

14. 13 Near total silence - 0 dB A whisper - 15 dB Normal conversation - 60 dB Lawnmower - 90 dB A car horn - 110 dB A rock concert or a jet engine - 120 dB Gunshot, firecracker - 140 dB Here are some common sounds and their decibel ratings: Here are some common sounds and their decibel ratings: The measurement for intensity or loudness is in DECIBELS (dB).

15. 14 Human Ear 20Hz to 20,000Hz Ultrasonic - Frequency higher than 20,000Hz Used in Sonar and Medical Diagnosis and treatment. Infrasonic (subsonic) - Frequency lower than 20Hz Elephant Communication and Butterflies flapping their wings, heavy machinery, thunder Supersonic- Motion that is faster than sound-do not hear it until it passes you Example-supersonic jets make sonic boom Best hearing between 100-2000 Hz https://www.youtube.com/watch?v=gWGLAAYdbbc

16. 15 Sonar - Echo - Sound Navigation Ranging Uses sound to estimate the size, shape and depth of underwater objects. Examples: Submarines, whales and bats Sonogram-picture of a baby inside mom Reflected sound waves Examples: Shouting in a cave or canyon

17. 16 How Loud is Loud? You know that you are listening to an 85 dB sound if you have to raise your voice to be heard by somebody else. For example, 8 hours of 90 dB sound can cause damage, but any exposure to 140 dB sound causes immediate damage (and causes actual pain). Any sound above 85 dB can cause hearing loss, and the loss is related both to the intensity of the sound as well as the length of exposure.

18. 17 Resonance prolonged vibrations of sound at their own natural frequency. an opera singer can shatter a glass if the singer resonates at the same frequency long enough

19. 18 SOUND in MUSIC Music has: definite pitch sound quality repeating rhythm Types of Instruments: Woodwinds(flute, clarinet) Brass(horns) Stringed(guitar, violin) Percussion(drum, piano) Acoustics = the science/study of sound

20. 19 Sound of Music rhythm – regular time pattern in a sound musical scale – set of frequencies (pitch) harmony – how sound works together to create effects desired by the composer beats – adding two waves that are only slightly different in frequencies noise-no set pattern and no definite pitch dead spots-areas where sound waves cancel out

21. 20 Sound of Music consonance – more than one frequency and it sounds good –frequencies are far enough apart dissonance – more than one frequency and it sounds bad –frequencies are too close together quality-describes the differences among sounds of the same pitch and loudness

22. 21 Sound of Music reverberation-many reflections of sound (echo) use of carpets, draperies to reduce reverberation interference-ability of two or more waves to combine and form a new wave 1. constructive-different waves arrive at the same place at the same time and cause an increase in loudness 2. destructive-one wave will arrive with the rarefaction of another wave and cancel each other causing a decrease in loudness