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Transcript
Slide 1
Slide 2
The Nature of Sound
https://www.youtube.com/watch?v=7cDAYFTXq3E
Slide 3
Important Vocabulary Compressional Wave Pitch Intensity
Loudness
Slide 4
What Sounds Did You Hear This Morning?
Slide 5
What Causes Sound? Sounds are produced by vibrations of objects
Voice is produced by the vibrations of your _________ The speed of
sound waves depends on the temperature and elasticity of the matter
in the medium Atoms are __________ in a solid. As a result sound is
transmitted faster in solids than in air. Compressional Waves:
matter vibrates in the same direction as the wave travels
Slide 6
Compressional Waves When you squeeze the coil together, the
crowded area is called a compression This compressed area expands,
spreading the coils apart and creating a less dense area The less
dense area of the wave is the rarefaction Have same characteristics
as transverse (wavelength, amplitude, frequencies and
velocities)
Slide 7
Wavelength: the distance between two compressions or two
rarefactions of the same wave Frequency: number of compressions
that pass a place each second Amplitude: depends of the energy
content of the wave
Slide 8
Comparing Media: Solid, Liquid, Gases The speed of sound
depends on The medium it passes through And the temperature of the
medium Air the most common medium Sound waves can be transmitted
through any type of matter Liquids and solids are better conductors
of sound than air because the particles have a greater influence on
each other.
Slide 9
Think about it If you were on the moon, would you be able to
hear someone else talking?
Slide 10
Speed of Sound As temperature of a substance increases, the
molecules move faster and therefore collide more frequently, making
sound travel faster Think about fireworks. Have you seen one
explode before you actually hear the explosion? What does this tell
you about the speed of light and the speed of sound?
Slide 11
Determining How Far Away Is a Thunder Storm? Count the time
interval between when you see a lightning bolt and when you hear
thunder. You see the lightning bolt before you hear the thunder
because
Slide 12
The Ear Being able to make sense of sound waves when having a
conversation involves three stages 1.Gathering and amplification of
the compressional waves by the ear mechanisms 2.Conversion of these
waves into nerve pulses 3.Decoding these signals to the brain
Slide 13
Frequency and Pitch Pitch: highness or lowness of a sound
Depends on the frequency of the sound waves The higher the
frequency, the higher the pitch Lower the frequency, lower the
pitch Noise has no definite pitch
Slide 14
Intensity and Loudness The intensity of a sound wave depends on
the amount of energy in each wave Intensity of a sound wave
increases as its amplitude increase Loudness is the human
perception of sound intensity.
Slide 15
Doppler Effect Doppler Effect: is the change in frequency of a
wave (or other periodic event) for an observer moving relative to
its source.