1. Intensity Determines Loudness
Sect. 16-3

2. How is Amplitude Related to Loudness? Pg 533
How did the loudness of the sounds compare?
How is amplitude related to loudness?
Challenge: Using what you learned from experimenting with the rubber band, explain why swinging a drumstick harder on a drum would make a louder sound than swinging a drumstick lightly.

3. Intensity determines loudness.
16.3
Intensity determines loudness.
A sound wave with a lower amplitude and energy
is perceived as a softer sound.
intensity
decibel
amplification
acoustics
CHAPTER
RESOURCES
SECTION
OUTLINE

4. Intensity determines loudness.
16.3
Intensity determines loudness.
A sound wave with a higher amplitude and energy
is perceived as a louder sound.
intensity
decibel
amplification
acoustics
CHAPTER
RESOURCES
SECTION
OUTLINE

5. Intensity determines loudness.
16.3
Intensity determines loudness.
intensity
A sound wave with a higher amplitude and energy
is perceived as a louder sound.
decibel
amplification
VISUALIZATION
Discover how particles move as sound waves move through the air.
acoustics
CHAPTER
RESOURCES
SECTION
OUTLINE

6. 16.3 intensity Intensity determines loudness.
decibel
The amount of energy of a wave, per wavelength. Intensity is associated with the amplitude of a sound wave and with the quality of loudness produced by the sound wave.
amplification
acoustics
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY

7. The more energy a sound wave carries, the more intense it is and the louder it will sound.
The intensity of a sound is the amount of energy its sound wave has.
A unit called the decibel(dB) is used to measure sound intensity
Amplitude is also a measure of wave energy; The greater the amplitude, the more intensity a sound wave has and the louder the sound will be.

8. Approximate Sound Intensities pg. 534
At more than 100 decibels sounds become very loud.
What is the source of the most intense sound in the picture?
What is the source of the least intense sound in the picture?

9. Why is it harder to hear a person talking far away from you than someone who is closer to you?
Sound waves spread out from their source in all directions. As they spread out, their energy spreads out, so the loudness decreases.

10. 16.3 decibel Intensity determines loudness. dB
The unit used to measure the intensity of a sound wave.
amplification
acoustics
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY

11. Controlling the Intensity of Sound
As the amplitude of a sound decreases, the frequency stays the same.
Change intensity without changing its quality by taking energy away from or adding energy to a sound wave.
Sound intensity can be controlled in many ways. Ex) muffler

12. 16.3 amplification Intensity determines loudness.
decibel
The strengthening of an electrical signal, often used to increase the intensity of a sound wave.
amplification
acoustics
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY

13. Amplification Increases the strength of an electrical signal.
Often used to increase the intensity of a sound wave.
Experienced when you listen to a t.v., radio, or stereo.

14. Amplification
When the frequency of an applied force matches the natural frequency of a system, large amplitude vibrations results in what’s called resonance.
Resonance explains why a glass shatters at a pitch that matches its natural frequency.

15. Amplification in a Stereo
Sound input comes from a microphone in the form of weak electrical signals
Transistors turn these signals into stronger ones, which are converted into vibrations in a coil in the speakers.
The coil is attached to a cone, which vibrates and sends out sound waves.

16. 16.3 Acoustics Intensity determines loudness.
decibel
The scientific study of sound; the behavior of sound waves inside a space.
amplification
acoustics
CHAPTER
RESOURCES
KEY CONCEPT
SUMMARY

17. Acoustics Involves how sound is produced
Involves how sound is received and heard
Refers to the way sound waves behave inside a space.

18. Compare and Contrast p.535
Imagine sound waves reflecting off the surfaces in the two photographs.
How do the reflections differ?
How would the addition of sound absorbing materials affect sound?

19. Intense sound can damage hearing
Damage and destroy the hair cells inside the ear
Ear damage can be lessened by wearing ear protection, such as ear plugs, or by covering the ears.
If the damage is slight, injured cells might be repaired, but such delicate cells could be permanently damaged.

20. 16.4 16-4: Human uses of sound: sonar ultrasound music telephone
Sound has many uses.
echolocation
16-4: Human uses of sound:
sonar
sonar
ultrasound
music
telephone
recording
CHAPTER
RESOURCES
SECTION
OUTLINE

21. 16.4 Bats use sound to locate objects. Sound has many uses.
echolocation
sonar
Bats use sound to locate objects.
CHAPTER
RESOURCES
SECTION
OUTLINE

22. Objects that can be detected by ultrasound
Food sources
Objects underwater
Inside of the body

23. Echolocation
Sending out of ultrasound waves and interpreting the returning echo.
Bats use sound to locate objects

24. Explore Echoes: How did sound change when you added the book?
How can an echo be used to detect an object?

25. Explore Echoes:
How did sound change when you added the book? The sound was louder with the book than without the book.
How can an echo be used to detect an object? An echo can be used to detect an object by reflecting off the object. If there is no object to reflect off, there would be no echo.

26. Sonar Instruments that use echolocation to locate objects
Stands for sound navigation and ranging
Can detect sounds from submarine propellers
Can locate underwater objects
Can find schools of fish
Can be used to map the ocean floor
Can be used to find sunken ships

27. Ultrasound can be safely used on humans
Ultrasound waves cannot be heard by humans, so they can be used on humans at very high intensities without damaging hearing.

28. Medical Uses of Ultrasound
Examine internal organs
Check the health of a fetus during pregnancy.
Can break up kidney stones

29. Sound waves can produce music – Characteristic sounds of instruments
All of the pitches of the instrument, along with the resonance of the instrument itself, produce the characteristic sound of the instrument.

30. Changing the pitch of a drum
Loosen or tighten the drum skin

31. While playing a particularly long and loud song on your guitar, it may become out of tune.
What has happened is that the strings have loosened and the pitch has changed.

32. Two inventions in the late 1800s that changed the world of sound
Telephone
phonograph

33. How telephones transmit your voice to another telephone
As you speak into the mouthpiece, your sound waves cause a thin disk inside to vibrate.
A microphone turns these vibrations into electrical signals.
These signals are sent over wire to a switching station.
Computers connect the wire to the other telephone.

34. How Edison’s Phonograph machine worked
Edison’s phonograph had a needle connected to a diaphragm that could pick up sound waves.
The vibrations of the sound waves were sent to the needle, which cut into a piece of foil.
To play back the sound, Edison used another needle to track along the grooves made in the foil.