How You Hear Sound

EQ: How do you hear sound?

The Ear

• There are three main sections of the ear:– Outer Ear– Middle Ear– Inner Ear

Outer Ear – Funnels sound waves

1. Curved section of ear collects sound

2. Ear canal – funnels sound to the ear drum. Few centimeters long

3. Eardrum – small, tightly stretched, drum like membrane. Sound waves make it vibrate

Middle Ear

Contains the body’s three smallest bones

hammer

anvil

stirrup

The hammer is attached to the ear drum. When the eardrum vibrates, the hammer does too. Then the hammer hits the anvil and shakes the stirrup

Inner Ear

Cochlea – cavity shaped like a snail shell, that is filled with liquid. Inside it is filled with more than 10,000 hairs.

Inner Ear

When the stirrup vibrates against the membrane, the vibrations pass into the cochlea. As the liquid moves, the hairs sway back and forth. The nerve endings attached to the hairs send a message to the brain …sound has arrived!

Hearing Loss

• Occurs from injury, infection or aging

“Old MacDonald ... Had Two Ears”

Verse One

Old MacDonald Had Two EarsE… I… E… I… …O

Three parts each so he could hearE… I… E… I… …O

With an outer ear, middle earInner ear hear, Inner ear there

Here an ear, there an earEverywhere an ear, ear

Old MacDonald Had Two EarsE… I… E… I… …O

Sound Waves enter the outer earE… I… E… I… …O

They hit the drum and it is clearE… I… E… I… …O

With a Wave, Wave here and a Wave, Wave thereHere a Wave, there a Wave, everywhere a Wave, Wave

An outer ear, middle earInner ear hear, Inner ear there

Here an ear, there an earEverywhere an ear, ear

Sound waves enter the outer earE… I… E… I… …O

Vibrations move the little bones E… I… E… I… …OMoving fluid so we hear tones E… I… E… I… …O

With a Whoosh, Whoosh here, and a Whoosh, Whoosh thereHere a Whoosh, there a Whoosh, Everywhere a Whoosh, Whoosh

Wave, Wave here and a Wave, Wave thereHere a Wave, there a Wave, everywhere a Wave, Wave

An outer ear, middle ear Inner ear hear, Inner ear thereHere an ear, there an ear Everywhere an ear, ear

Vibrations move the little bones E… I… E… I… …O

This moving fluid signals my brain E… I… E… I… …OI hear the sound of a jet airplane E… I… E… I… …O

With a Zoom, Zoom here, and a Zoom, Zoom thereHere a Zoom, there a Zoom, everywhere a Zoom, Zoom

Whoosh, Whoosh here, and a Whoosh, Whoosh thereHere a Whoosh, there a Whoosh, Everywhere a Whoosh, Whoosh

Wave, Wave here and a Wave, Wave thereHere a Wave, there a Wave, everywhere a Wave, Wave

An outer ear, middle ear Inner ear hear, Inner ear thereHear an ear, there an ear Everywhere an ear, ear

Sound Waves signal my own brain!!!E… I… E… I… …O !!

Class Work and Homework

• Fill In – What did I learn– Confused– Say– Read pages O 62 – O 64– Questions 1-5, page O 64