1. Chapter 15-1
Sound

3. What causes sound? Every sound is produced by an object that vibrates.
Sound waves are longitudinal waves

4. Sound
Longitudinal Waves –made of compressions and rarefactions.

6. Sound
Sound waves can travel through any type of mattersolid, liquid, or gas.
Most is through air

7. Sound Matter that a wave travels through is called a medium
Cannot travel through empty space

8. Sound:
Speed of Sound – 340 m/s or 760 mi/hr
In Air

9. Sound
Sound depends on the substance the medium is made of

10. Sound Slow – gas Medium – liquid Fast – solid
Depends on spacing of molecules

11. Sound and Temperature Increase Temperature Increase molecule movement
Increase Speed of Sound

12. Sound Speed Sound Speed - Doesn’t depend on loudness of sound
Loud and soft sounds travel through a medium at same speed

13. Intensity and Loudness
The amount of energy a wave carries corresponds to its amplitude.

14. Intensity
Intensity - amount of energy that flows through a certain area in a specific amount of time.
Decibel – unit of intensity
Loudness - human perception of sound intensity.

18. Pitch Pitch - how high or low a sound seems to be.
Related to frequency (Hz)
Human : 20 – 20,000 Hz

21. Infrasound and Ultrasound
Infrasound – low frequencies < 20 Hz
Ultrasound – high frequencies > 20,000 Hz

22. Hearing and the Ear: See Diagram pg 496
Outer Ear – Focuses Sound Waves
Middle Ear
Ear Drum – Amplifies Sounds Waves
Anvil
Hammer
Stirrup
Inner Ear
Cochlea – Turns sound waves into nerve impulses
Basilar Membrane
Auditory Nerve – Sends messages to the brain

24. Sonar
Sonar –
Sound
Navigation
And
Ranging

25. Ultrasound and Sonar D=vt
Distance = Speed of Sound x The Time for it to travel