VOCAB PREVIEW—DO YOU KNOW ANY OF THESE WORDS?
Sound wave
Pitch
Loudness
Pupil
Nerves
illumination
opaque
Optical illusions
outer ear
frequency
Decibel
Iris
Nearsightedness
transparent
reflection
inner ear middle ear
doppler effect
tinnitus
cornea
lens
retina
farsightedness
Translucent
diffraction
SOUND WAVES
• A sound wave is a longitudinal wave
generated by a vibrating material.
• It is then carried through a medium
and transfers energy.
• Sound waves travel in all directions
away from their source
• Sound has to have a medium
• Sound can not travel in a vacuum
Middle Ear
Three bones
(hammer, anvil, stirrup)-
act as levers to
increase the size of
the vibration
Inner Ear
Outer Ear
collects sounds
Turns vibrations
into signals for the
brain
Sound is:
1. Collected (by outer ear)
2. Amplified (by middle ear:
hammer, anvil,
stirrup)
3. Converted to Electrical signals
for the brain (by inner ear)
1. Sound waves vibrate the ear drum
(lightly stretched membrane in middle
ear)
2. Vibration of ear drum vibrates
hammer-anvil-stirrup
3. Oval window vibrations create waves
in liquid in cochlea
4. Movement of liquid causes tiny hair
cells to bend
5. Bending of hair cells stimulates
nerves, sends electrical signals to
brain
Do Not Copy
HSW Sound/How we hear VIDEO
(not saved)
HSW New Hearing Implant VIDEO
The speed of sound depends on the
1. Medium
2. Temperature
Cool
AIR
Warm
LIQUID
Slower
SOLID
Faster
Fastest in solids
Slowest in gases
Pitch- how high or low a sound seems
Frequency- (number of waves in a given amount
of time)
Frequencies Heard by Different Animals
bat
2,000- 110,000 hz
porpoise
75- 150,000 hz
Cat
45-
Beluga
64,000 hz
1,000- 123,000 hz
Elephant
16-
12,000 hz
Human
20-
20,000 hz
dog
67-
45,000 hz
Doppler effect: apparent change in
frequency of sound caused by motion of
observer or source.
Sound waves
are moving
forward/same
direction of
the train:
Constructive
interference
makes it
sound louder.
http://www.windows2universe.org/earth/images/doppler_e
ffect_jpg_image.html&edu=high
Loudness- how well a sound can be
heard
Decibel-measures loudness
0 dB: softest humans can hear
120 dB: hurts
Which one is loud?
Which one is soft?
How do you know?
HEARING PROBLEMS
Damage to the cochlea or any part of
the inner ear usually results in
permanent hearing loss.
Tinnitus- caused by long term
exposure to loud sound
PROTECT YOUR HEARING
HOW CAN YOU PROTECT YOUR HEARING?
Use ear plugs
Use a lower volume
Move away from loud sounds
LIGHT WAVES
• Are transverse waves
• Can travel through a vacuum
(empty space)
• Travels faster than sound
• Faster in empty space
• Slowest in solids
• Travels in straight lines
1. Cornea- membrane that
protects the eye
HUMAN EYE
2. Pupil-opening of the eye
that light passes through
3. Iris-controls size of pupil
(colored part)
4. Lens-refracts light to
focus an image on back of
eye
5. Retina- back of eye that
pick up light with rods &
cones
6. Nerves-attached to rods
& cones send info to brain
Rods: sense dim light
Cones: sense bright light
Light bounces off an object and enters our
eyes. We see red because red light is
reflected off of the red object.
Near sightedness
person can see something
clearly if it is nearby; blurry
vision of things far away;
eye is too long
Far sightedness person
can see something clearly
far away; blurry vision of
things up close; eye is too
short
Illumination- We see objects because
a light is reflecting off of it into our eyes.
We see a light source even in the dark
because it goes directly into your eyes.
Room with a
lamp on
Room with a
lamp off
Materials can be classified
in 3 ways
1. transparent clear
2. translucent
cloudy
slightly
3. opaque light cannot
OPAQUE
TRANSLUCENT
TRANSPARENT
Reflection: when the wave bounces back
towards the source
Refraction: the bending of a wave as the wave
passes from one medium to another at an angle
Diffraction: the bending of waves around a
barrier or through an opening
Diffraction
What do you
notice?
Optical Illusions
Optical Illusions
Optical
Illusions
http://www.colorbasics.com
/Optical-Illusions/
What do
you see?
HUMAN EAR
HUMAN EYE
Turn to your neighbor. Name 2 new
things you learned about the
ear and the eye.