How Do Sound Waves Travel?
Chapter 12 Lesson 3
Pages 422-429
How Do We Hear Sounds?
• When the vibrations travel through air and
reach your ears, they make your eardrum
vibrate.
• Those vibrations travel through bones and
tissues until they reach your inner ear.
• Special cells in your inner ear change the
vibrations into electrical signals.
• The electrical signals travel along a nerve to
your brain and it recognizes the signals and
you hear the noise!
Your Ear
1.
2.
3.
4.
Outer Ear- catches sound
waves and funnels them
inward to your eardrum.
Eardrum- the sound waves
make your eardrum vibrate.
Vibrations from the eardrum
travel along three tiny bones,
called the hammer, anvil, and
stirrup.
Cochlea- Bones pass
vibrations to a snail-shaped
organ called the cochlea.
Hairlike cells inside change
vibrations into nerve signals.
Nerve signals from the
cochlea travel along this
nerve to your brain.
1
3
2
How Hearing Works
Reflection
• Light waves and Sound waves are behave in a
similar way when they come in contact with
surfaces.
• When sound waves hit a flat, smooth surface,
they are reflected back in the same pattern.
This is what causes an echo.
• When sound waves hit a rough surface, they
are scattered all over.
• The sound waves are bouncing off the surface,
a process called reflection.
A flat, smooth surface
preserves the pattern of
the sound waves.
A rough, uneven surface
destroys the pattern of the
sound waves.
Absorption
• Some materials stop
the sound waves from
reflecting or traveling
any farther. This
process is called
absorption.
• Walls, curtains,
carpet, etc. “absorb”
the vibrations and
thus cause there to
be no more sound.
Transmission
• You can hear sounds when waves keep vibrating through some
kinds of material.
• They travel through air or other matter, all the way to your inner
ear.
• The sound waves keep moving through the material to produce
sound– a process called transmission.
• When we hear someone in another room, the sound waves are
being transmitted through the air in that room, through the wall,
through the air in your room, and then into your ear.
• Materials that can vibrate are materials that can transmit sound.
• How do sound waves travel through different materials?
Quietly take out your remote
______ means that sound waves keep
moving through materials to produce sound.
A. Reflection
B. Absorption
C. Transmission
A wave’s bouncing off a surface is called
___________.
A. Reflection
B. Absorption
C. Transmission
__________ stops sound waves from
traveling any farther.
A. Reflection
B. Absorption
C. Transmission
Suzy yells her friend’s name very loudly. What
might she hear when the sound waves bounce off
the smooth surface of a cliff?
A. An echo
B. Silence
C. A jumble of sounds
Which part of the ear acts as a funnel for
sound waves?
A.
B.
C.
D.
Cochlea
Eardrum
Hammer, anvil, and stirrup
Outer ear
Sound waves cause which part of the ear to
vibrate first?
A.
B.
C.
D.
Cochlea
Eardrum
Hammer, anvil, and stirrup
Outer ear
In which part of the ear are vibrations
changed to nerve signals?
A.
B.
C.
D.
Cochlea
Eardrum
Hammer, anvil, and stirrup
Outer ear
Carpet absorbs sound waves.
A. True
B. False