What are some practical ways we use sound energy?

The Human Ear

IntroductionYour 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 EarContains 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 SoundsHigh 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 LoudnessThe 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-Oz-Goes-Inside-the-Human-Ear-Video

http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/

http://www.noiseaddicts.com/2009/02/hearing-test-hear-like-teenager/

http://www.betterhearing.org/hearing_loss/how_we_hear/virtualeartour.swf

http://video.about.com/pediatrics/Ear-Pressure.htm