CHAPTER 17&18 NOTES
KONICHEK
I. WAVE- A rhythmic disturbance
through matter or space
A. Medium- any matter through
which the wave travels through
B. Mechanical wave- waves
which require a medium
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Light waves
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A. Travel through empty space
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B. Travel at 3x108m/s
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c. Called electromagnetic waves
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1. Visible light, others
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2.Combination of 2 forces, the
electrical and magnetic forces vibrating at
right angles to each other
 III. WAVES TRANSFER ENERGY
 A. Waves have the ability to do work.
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1. Sound on eardrum
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2. Tsunami/Tidal waves
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IV. ENERGY SPREADS OUT AS A
WAVE TRAVELS
A. As distance increases a sound wave
loses some of it’s energy
1. Energy spreads out over distance,
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V. VIBRATIONS AND WAVES
A. Waves are related to vibrations.
1. Vibrations are created by energy
B. Vibrating objects produce waves
C. Vibrations involve transformation of
energy.
1. Oscillating spring
D. Waves can pass through a series of
vibrating objects.
1. The Ke of the wave can pass through
Harmonic motion
VIBRATIONS CAUSE WAVES
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VI. Transverse and Longitudinal
waves
A. Transverse wave- A wave which
vibrates at right angles to the direction it
moves
1. Water wave, light waves
B. Longitudinal waves- waves which
vibrate in the same direction as they move
1. Sound wave
TRANSVERSE WAVE
SOUND WAVELONGITUDINAL WAVE
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VII. Surface wave-occurs on the
boundary area between different
mediums
A. Move both perpendicular and
parallel ( water waves)
VIII. CHARACTERISTICS OF
WAVES
A. wave properties
1. All transverse waves look
about the same
a. Sine curve- S shaped
1. Sine wave- Waves
which are made up of Sine curves.
 2. Crest- highest point if a wave
3. Trough- the lowest point of a wave
4. Amplitude- This is the height of a wave
from a fixed point( normal)
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a. Determines the amount of energy
in a wave.
 5. Wavelength- the distance from one
point on a wave to the same point on the
next wave
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a, Units are cm, angstroms,
nanometers
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AMPLITUDE – THIS IS THE
HEIGHT- DETERMINES ENERGY
WAVELENGTH
WAVELENGTH
DETERMINATION
 6. frequency- The number of waves past a
point in one second
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a. Units Hertz( Hz)
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b. Wave Speed= wavelength x frequency
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1. Depends on the medium
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a. Sound waves
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B Kinetic theory- the structure of the
matter will determine the speed
a. solids, liquids, gases-- examples
C. Speed of light is finite 3x108m/s
1. 7 ½ times around the Earth in 1
second
D. Doppler effect- The apparent change in
frequency of the wave caused by the
motion of the source or the observer
1. Towards the source - wavelength is
shorter( blue, higher pitch)
2. Away from the source- wavelength is
longer( red or lower pitch)
DOPPLER EFFECT
 IX. wave interactions
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A. Reflection- The bouncing of a wave off a barrier.
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1. Incident wave-source to barrier
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2. Reflective wave-barrier to detector
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3. Angle of incidence-angle formed from the
normal to source
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4. Angle of reflection-angle formed from the normal
to detector
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5. Law of Reflection- the angle of incidence equals
the angle of reflection
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B. Diffraction-The bending of a wave around
a barrier.
1. Diffraction gratings- pieces of
glass or plastic with many parallel slits
a, Spreads out white light into the
spectrum
b used to determine the
composition of celestial objects
REFLECTION
REFLECTION OF SOUND-ECHO
C. Refraction- The bending of light as it
passes from one medium to another
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1. Change in the speed of the
wave
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REFRACTION OF LIGHT
REFRACTION IN WATER
SEPERATION OF WHITE LIGHT
• D. Interference- The result of when waves collide
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1. Constructive- crest meets crest and troughs
meet troughs
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a. Waves reinforce each other
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2. Destructive- crest meets trough
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a. Cancel each other out.
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3.standing waves-The reflected wave have the
same amplitude, speed and frequency.
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a. Don’t move through the medium- cause the
medium to vibrate
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Constructive Interference
DESTRUCTIVE INTEREFRENCE
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X SOUND WAVES
A. PRODUCING SOUNDS
1. VIBRATION -Needs energy- The back and forth motion of
matter
B Sound wave- a longitudinal wave produced by a vibration in a
medium
C. SPEED OF SOUND- Depends upon the medium, it’s traveling
through, and the temperature of the medium
1. in air at 20 degrees Celsius 340m/s
2. in solids 15 times faster
3. in liquids 4 times faster
D. The speed of sound changes as the temperature of the medium
changes
1.speed increases or decreases .6m/s for each degree
Celsius
XI. INTENSITY AND LOUDNESS
A. Loudness is the perception of the
rate at which sound energy enters the ear.
B. Intensity- The actual measurement
of the rat-. high intensity waves produce
large amplitude and this produces a loud
sound.
C. Intensity level- measured by
comparing sounds to the lowest possible
sound heard by humans
1. measured in decibels( dB)
a. breathing =10 dB, chain
XII. DANGERS OF SOUND
A. intensity levels over 90dB cause
permanent ear damage
B. a single exposure over 150 dB can
break the eardrum.
1, ear protection in places which are
extremely loud
C. Noise- bothersome, harsh, unappealing
sounds.
 XII FREQUENCY AND PITCH
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A. Pitch- the ears perception of frequency
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1. high frequency= high pitch
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2, low frequency= low pitch
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B. Ranges of frequency
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1. humans- 20 to 20,000 hz
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2. dogs- 15 to 50,000
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3. bats 1000 to 120000
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C ultrasonics- sounds above the human
range of hearing.
 XIV. SOUND WAVE BEHAVIOR
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A. echoes- the reflected sound wave is an
echo
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1. echoes can’t be detected if the
time between the sound and the echo is at
least .05 seconds.
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B. Sonar- Uses the reflection of sound
waves as an information gathering process.
SOUND NAVIGATION AND RANGING
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C. DIFFRACTION OF SOUND
 C. DIFFRACTION OF SOUND
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1. sounds bend around corners
rather easily because of their long
wavelength
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D. Refraction of sound waves- Sound
traveling through differnt densities of air.
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1. during the day sounds don’t
travel as far because of the warm air
refracting the sounds upward,
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2. at night the warm air above
refracts the sounds downward so the sounds
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XIII. HEARING
A. regions of the ear- outer, middle and inner
1. outer ear is fleshy and funnels sounds into the eardrum
a. eardrum- a tympanic membrane which vibrates
when struck by sounds
2. Middle ear- 3 bones composition
a. hammer( malleus)
b. anvil( incus)
c. stirrup( stapes)
3. Inner ear- Cochlea and semicircular canels
a. changes the mechanical sound wave into the
electrical impulse which is sent to the brain.
The ear-who’s listening?
VI. MUSIC
A. Regular patterns of sound
B. Musical inturments- produce sounds
by vibrating strings or columns of air, or
vibrating membranes
1. rely on standing waves.
C, Classification of instruments
1. strings- Use a vibrating string and
a resonating cavity
a. pitch depends on the diameter
and the length of the string
2. Woodwinds- Use a vibrating reed,
and pitch is changed by changing the
length of the column of air
3.BRASS- The lips vibrate and the pitch is
changed by using a slide or keys which
change the lengt of the air column
4. drums- they keep a beat
a. Tympany- able to change the
pitch by regulating te tightness of the
membrane
D. Resonance-The vibrating of the body
of the insturment at the same frequency as
the nusical notes being played.
VIII. ULTRASOUND AND SONAR
A. SONAR- SOUND NAVIGATION
AND RANGING
1. used to determine the depth of
waters, and schools of fish
2. distance calculations from time.
a. D=VT, V is the velocity of
sound in water, T is the time it takes for
the return wave.
IX. ULTRASOUNDS IN MEDICINE
a. In pregnancies to detect any defects
b. Echogram of the heart to see if the
muscle is fully functioning
c. Advantages- does subject tissue to
x-ray radiation which may cause tissue
damage
d. High frequency waves can pass
through soft tissue very easily
CHAPTER 18 NOTES
 XIV. NATURE OF LIGHT
 A. Theories on the composition of light
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1. Wave model-Light travels in waves
a. interference patterns like a wave- Young’s
observation
b. transverse wave-electromagnetic in nature
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c. electric and magnetic waves vibrating at 90
degrees to each other
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d. Einstein's photoelectric effect- won the noble prize
for the discovery ( EARLY QUANTUM THEORY)
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1. Problem- why do electrons fly off metal when
struck by high energy light
 2. Particle theory of light- Light occurs in
nature as discreet little bundles of energy
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a. photon-a packet of radiant energy.
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b. No mass
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c. Energy of the photon is dependant
on the wavelength of light
 2. Light is weird- sometimes it acts like a
wave, other times acts like a particle.
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B. Energy of light is proportional to the frequency of the
light.
1. high frequency short wavelength high energyBlue light.
C. Speed of light depends on the medium-3xlO8 m/s in
space.
1. according to most scientists is the speed limit of
the universe- special relativity.
2. E=mc2
D.Light intensity- the quantity which measures the
amount of light illuminating a surface
1. obeys the inverse square law. I=1/d2
XV.ELECTROMAGANETIC SPECTRUMa listing of all the possible kinds of light
energy from short to long wavelength.
A.Cosmic rays-energy photons produced
by the reactions of high energy nuclear
transformations-such as the creation of the
universe.
1. studying- the structure and
formation of matter.
2.Big bang- the event which
supposedly created the universe.
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B.Gamma rays- High energy photons
1. produced by the decay of a
neutron
a.Ne- + e+ + protons +
neutrinos
2.Used in cancer therapy.
3. Gamma ray burst- These are stars
near the end of their life which explode
in huge burst of gamma rays- if they
C.X-Ray- Caused by bombarding tungsten
with fast moving electrons.
1. Used to examine inside the body
2. Given off when a black hole sucks in
matter from a binary star
 D. Ultraviolet
 1. responsible for suntan, sunburn,
skin cancer
 2. earth is protected by the Ozone
layer- filters out UV
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 3. Used in surgery to sterilize the
surgical equipment.
HERE YA GO SUN BATHERS
Cancerous growth- SUNBATHERS!
 E. Visible light- Detected by living organisms
with their eyesight
 1. Composed of R.O.Y. G. B.I.V. this is
from long to short wavelength.
 2. Red light is bent the least and blue light
is bent the most in a rainbow
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a. Blue has shorter wavelengths, red
has longer
Visible spectrum- ROY G BIV
• F. Infra Red- This is the radiation given
off by warm objects.
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1. Pit Vipers detect warm blooded prey
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2. night time photography
G. Microwave- short wave radio
1 Used in communications
2.cooking- water must be presentthe water molecule resonates at the
same frequency, so it causes objects
to warm..
• H. Radio waves- Used in communications
• 1. AM- amplitude modulations- The height
of the wave is being changed, a.news, sports
types of programming b. Travels a longer
distance- bounces off the ionosphere.
• 2. FM- the frequency of the wave changes a.
Usually musical programming.
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U. Television- The combination of an audio
and visual signal
1 .High definition TV - combines the
technology of computers and TV to get
more pixels on the screen, hence the
picture is so much better.
• XVI Polarized light- This is light of only one
plane.
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A. Polarized filters- This allows light of
only 1 plane to pass.
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1. Reduces glare- That’s why they
are good to wear when you’re in a boat or
in snow covered areas.