Transcript Intensity determines loudness

 When you listen to music, you hear
both high and low sounds.
 The characteristics of higher or
lower sounds is called a pitch.
 The frequency of a sound wave
determines the pitch of a sound you
will hear.
 A high frequency wave with short
wavelengths such as the flute make
a high pitched sound.
 A low frequency wave with long
wavelengths , such as a tuba make
a low pitched sound.
 The unit for measuring frequency
and also pitch is hertz. A hertz is
one complete wave, or cycle, per
second.
 The highest a human ear can hear
is about 20,000 Hz per second
,which is also known as
ultrasound.
 Each musical instrument and
each human voice has its own
particular sound, which is called
the sound quality or timbre.
 Sound waves cause particles to
vibrate through the air.
 These vibrations have a
frequency or number of cycles
per second.
 All objects have a frequency at
which they vibrate called a
natural frequency.
 Resonance occurs when the
strength of a sound wave
combines with an objects
natural frequency.
 The Doppler effect is the
change in perceived pitch that
occurs when a object is moving
such as an ambulance or a
train.
•How does energy
determine loudness
according to sound?
•The more energy
sound waves carry
the louder it will
sound to listeners.
•The intensity of a
sound is the amount
of energy its sound
wave has.
 The unit to measure sound
intensity is a decibel.
 Some of the softest sounds are less
than 10 decibels and very loud
sounds are usually more than 100
decibels.
 Amplitude is related to wave
energy, so the greater the intensity
a sound wave has the louder the
sound will be.
 All sound waves spread out
as you get further away from
the sound wave the intensity
of that sound will decrease.
 As sound waves travel the
sound gets weaker and
weaker and then finally
undetectable
 The pitch does not get
weaker, therefore even as the
amplitude decreases the
frequency will stay the same
 Sound intensity can be controlled,
an example would be mufflers on
cars and trucks.
 A muffler is designed to absorb
some of the energy of the sound
waves and then it will decrease its
amplitude.
 Sound Waves can also be amplified.
 Amplification is the increasing
of the strength an electrical
signal.
 It is used to increase the
intensity of a sound.
 An example of this would be
when you listen to a stereo.
 The scientific study of sound is
called acoustics.
 Acoustics involve how sound is
produced and how it is received
and heard by humans and
animals
 Acoustics can also refer to the
way sound waves behave in a
space.
 Sound can also damage hearing,
continual exposure to 90 db or
louder can damage or destroy the
hair cells needed to hear.
 Noises above 130 db are
especially dangerous. Noises
above 140 db are even
painful.