SOUND WAVES are the result of VIBRATIONS

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SOUND WAVES are the result of VIBRATIONS
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A SOUND WAVE is a LONGITUDINAL WAVE but it is
drawn as a transverse wave
Since a sound wave consists of a repeating
pattern of high pressure and low pressure regions
moving through a medium, it is sometimes referred
to as a pressure wave
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Sound is a MECHANICAL WAVE

• Sound requires a medium
• Sound can travel in a solid, liquid, or gas

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The Speed of SOUND in AIR

• The speed of sound 331 m/s at 00C
• The speed of sound increases about 0.6 m/s for
  each 0C rise in temperature
• Sound travels faster in liquids and fastest in
  solids than in air (a gas) because the molecules
  are closer together

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The Frequency of a SOUND WAVE

• Represents the PITCH or a NOTE on a MUSICAL SCALE

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Frequencies of Sound

• The human ear is capable of detecting sound waves
  between 20 Hz to 20 000 Hz.
• Any sound with a frequency below the audible
  range of hearing is an infrasound and any sound
  with a frequency above the audible range of
  hearing is known as an ultrasound.
• Dogs can detect frequencies between 50 Hz and 45
  000 Hz.
• Bats, who must rely on sound echolocation for
  navigation and hunting, can detect frequencies as
  high as 120 000 Hz.
• Dolphins can detect frequencies as high as 200
  000 Hz.
• An elephant possesses the unusual ability to
  detect infrasound, having an audible range from
  approximately 5 Hz to approximately 10 000 Hz.

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The AMPLITUDE of a SOUND WAVE

• Represents the LOUDNESS of the sound

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LOUDNESS in Decibels
0 Silence
10 Heartbeat
20 Whisper
30 Soft piano
50 Soft talking
60 Conversation
80 Street traffic
90 Food blender
110 Thunder
120 Painful sounds
170 Jet engine
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Resonance

• Resonance occurs when two interconnected objects
  share the same frequency.
• Resonance occurs when one object vibrating at the
  same natural frequency of a second object forces
  that second object to vibrate.

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The Doppler Effect
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The Doppler Effect