Transcript What are some practical ways we use sound energy?

What are some practical
ways we use sound
energy?
The Human Ear
Introduction
Your
ear converts sound
waves into nerve impulses
that your brain interprets.
Parts of the Ear
 The
Outer Ear
 Contains the pinna, ear canal and
ear drum
 The Middle Ear
 Contains three bones: hammer,
anvil & stirrup
 The Inner Ear
 Contains the cochlea and auditory
nerve
The Outer Ear
 The
pinna is specially shaped to
gather and focus sound waves and
direct them into the ear
 The ear canal is a hollow tube that
carries the sound waves to the ear
drum
 The sound waves hit the ear drum,
causing it to vibrate. The ear drum
transmits these vibrations into the
inner ear where they are amplified.
The Middle Ear
 Has
the smallest bones in the human
body: hammer, anvil and stirrup
 Their job is to amplify the vibrations
of the eardrum and transmit it into
the inner ear.
The Inner Ear
 The
cochlea is a snail-shaped tube
that is lined with receptors that
respond to sound
 The receptors are tiny hair cells that
shake back and forth in response to
sound waves
 When they shake, the hair cells
create nerve impulses which go to
the brain along the auditory nerve
Anatomy of the Human Ear
High vs. Low Sounds
 High
pitch sound carry more
energy and travel further into
the cochlea
 Lower pitch sounds carry less
energy and don’t travel as far
into the cochlea
Intensity and Loudness
The
intensity of a sound
wave is the amount of energy
the wave carries per second
through a unit area.
Loudness, or sound level, is
measured in decibels (dB)
Sound
Loudness
(dbs)
Hearing
Damage
Average Home
40-50
Loud Music
90-100
After long
exposure
Rock Concert
115-120
Progressive
Jet Engine
120-170
Pain
Space shuttle
engine
200
Immediate and
irreversible
Frequency
 Frequency
is measured in Hertz (Hz)
 The frequency of a sound wave is the
number of vibrations that occur per
second


Meaning, a frequency of 50 Hz means fifty
vibrations per second.
People hear sounds with frequencies
between 20 HZ and 20,000Hz.
Ultrasound
sound waves with frequencies above the
normal human range of hearing.
-
Infrasound
- sounds with frequencies below the
normal human range of hearing.
http://www.oprah.com/oprahshow/Dr-OzGoes-Inside-the-Human-Ear-Video
 http://www.noiseaddicts.com/2009/03/ca
n-you-hear-this-hearing-test/
 http://www.noiseaddicts.com/2009/02/he
aring-test-hear-like-teenager/
 http://www.betterhearing.org/hearing_los
s/how_we_hear/virtualeartour.swf
 http://video.about.com/pediatrics/EarPressure.htm
