Vocabulary
•Ch. 10 •Ch. 12
• P. 290
(1-4)
• P. 296
(1-7)
• P. 303
(1-5)
•Ch. 11
• P. 327
(1-6)
• P. 354
(1-3)
P. 360
(1-7)
•Ch. 13
• P. 384
(1-5)
Waves
Notes
Waves Notes
• LINEAR MOTION= • HARMONIC
motion from one
point to another
without repeating.
–
–
–
–
Distance
Time
Speed
Acceleration
MOTION= motion
that repeats over and
over.
HARMONIC MOTION
• Cycle (cyclic motion) = a unit of motion that
•
repeats.
Oscillator (oscillating system) = a system
that shows harmonic motion.
• clocks
• solar system
• Seasons
• music & musical instruments
• cell phones
• fm radio
• Period = time it takes for one cycle to occur.
Frequency
= the number of cycles per second.
unit = Hertz (Hz) 1 Hertz = 1 cycle/second
ex: human heartbeat = ½ to 2 beats per second
ex: human voice = 100 to 2000 cycles per second
Amplitude
• a measure of how large the cycle is.
• This is the energy of a wave.
ex: waves = height of the wave
sound = volume
WAVES
Transfer energy from place to place without
transferring matter
• a disturbance in a medium.
• medium = matter that are able to carry a
wave.
– ex: air carries sound waves
–
water carries waves
QUESTION: Can sound travel
in space, in other words, could you
hear in outer space?
ANSWER: NO! Sound requires
a medium to carry its energy. Since
matter does not exist in space the
sound energy would have nothing
to travel on.
Transverse Waves
• = oscillations that are perpendicular (90º)
to the direction the waves is moving.
•
oscillation^
wave motion >
ex: water, light, S-waves in an earthquake
Longitudinal (compression) Waves
• = oscillations that are in the same
directions as the motion of the waves.
•
oscillation>
wave motion >
•
ex: sound, shock waves, P-waves -- earthquake
NOTE CHECK
TAKE 2 MINUTES:
With a partner, check each
other’s notes to be sure both
filled in all blanks
WAVES
Can be:
Can be:
transverse
compressional
Matter moves:
@ right angles to wave direction
Matter moves:
Along wave direction
Wavelength is measured:
Wavelength is measured:
Crest to Crest
Compression to
Compression
Examples:
Examples:
Wave on a rope
Sound waves
Waves on a lake
Shock waves
PROPERTIES OF WAVES
WAVE TERMS
• Frequency (f) = waves per second
(measured in Hertz)
– known as Pitch in sound & music
• Amplitude = the height of the waves,
the energy of the wave.
– Measured from the resting position to
the crest.
• Wavelength (λ) = the length of one
cycle. Distance from a point on a wave to
the identical point on the next wave.
Which of the graphs has an
amplitude of 10 centimeters?
5
Name five parts of a wave:
1. __________________________________
2. __________________________________
3. __________________________________
4. __________________________________
5. __________________________________
3
1
Compare and contrast the 2 types of waves:
1. Both = _______________________________
2. Matter = ______________________________
3. Matter = ______________________________
A wave is =
1. _____________________________________
WAVE SPEED
• Speed = the velocity the wave is traveling.
• velocity = wavelength x frequency
•
v=λx f
•
units
f = Hertz (Hz)
λ = meters (m)
v = meters/second (m/s)
Ex: An ocean wave has a frequency of 2 Hz and a speed
of 20 m/sec. What is the wavelength of this wave?
λ = v/f
λ = 20 m/s ÷ 2 Hz = 10 m
Examples of the Speed of Waves
• Speed of Light
300,000,000 m/s
300,000 km/s
186,000 miles/s
NOTE CHECK
TAKE 2 MINUTES:
With a partner, check each
other’s notes to be sure both
filled in all blanks
Examples of the Speed of Waves
• Speed of Sound
• Calculate the Speed
– Approx 340 m/s
– Approx 770 miles/hr
– This will vary a great deal due to
temperature and atmospheric
pressure
of Sound
WAVES INTERACTIONS
what results from waves hitting
objects
• Reflection = The wave can bounce off
and go in a new direction.
• Angle of Incidence = inbound angle
• Angle of Reflection = outbound angle
• measured from the perpendicular and
both angles are EQUAL
Which is the angle of incidence?
Which is the angle of reflection?
Refraction = The wave can pass
straight into and through the obstacle
and are bent due to the change in
density of the medium.
Diffraction = The wave can
bend around or through holes in
the obstacle.
Absorption = The wave can
be absorbed and disappear.
NOTE CHECK
TAKE 2 MINUTES:
With a partner, check each
other’s notes to be sure both
filled in all blanks
WAVE INTERFERENCE
• when 2 or more waves meet.
• Constructive Interference = When waves
meet “in phase” trough to trough or crest to
crest. The resulting waves become larger.
• ex: Sound = resonance
Resonating Chambers = sinuses, guitar,
musical instruments
Wind Tacoma Narrows Bridge collapse
in the 1940s
Tacoma Narrows Bridge
“in phase”
WAVE INTERFERENCE
• Destructive Interference = When
waves meet “out of phase” crest to
trough. The resulting waves become
smaller or even cancel each other.
•
ex: Dissonance = sound waves meet
out of phase and noise results.
“out of phase”
THE DOPPLER EFFECT
• radar speed detectors
• metrology to detect wind speeds & on
coming weather fronts
• very noticeable in auto racing
• Approaching Object = sound wave are
•
compressed due to the speed of the
approaching object thus increasing the
frequency or pitch of the sound of the object.
Departing Object = sound waves are
stretched because the object is moving away
from the listener thus decreasing the frequency
or pitch of the sound of the object.
NOTE CHECK
TAKE 2 MINUTES:
With a partner, check each
other’s notes to be sure both
filled in all blanks
THE ELECTROMAGNETIC SPECTRUM
• Electrons = the negatively charged
particle in the atom is involved in light.
– Electrons can absorb energy by various ways
causing them to jump to a higher energy
level(s).
– Then they give off energy in the form of light
when they move from the higher to lower
energy level(s).
Parts of the electromagnetic
spectrum
• Radio waves
• Microwaves
• Infrared
• Visible Light
Longest Wavelength
Lowest Frequency
– ROY G BIV
• Ultraviolet
• X-rays
• Gamma rays
Short Wavelength
Highest Frequency
THE ELECTROMAGNETIC SPECTRUM
• Radiowaves
(1 km to 30 cm)
– ex: AM & FM radio, TV
signals
• Microwaves
(30 cm to 1 mm)
– ex: microwave ovens,
cellular communication
• Infrared
(1 mm
to 70 nm)
– ex: heat, sensors,
guidance systems
• Visible Light (70 nm - 400 nm)
– ex: ROY G BIV
• Ultraviolet
– ex: sunburns, harmful
to eyes, disinfect by
killing bacteria
• X-Rays
– ex: medical & dental
uses, inspect metal
welding
• Gamma Rays
– ex: originate from the
sun, atomic radiation
ROY G BIV
• Red
• Orange
• Yellow
• Green
• Blue
• Indigo
• Violet
Longest wavelength
Shortest wavelength
Lowest frequency
Highest frequency
Visible Light
• Optics = the study of light
• Lasers = a single frequency of light
COLOR
• Primary Colors of Light
the color of transmitted
light you see.
The light source
–Red
–Green
–Blue
• Red + Green + Blue = White
COLOR
Primary Colors of Pigment
A pigment is a colored
material that is used to
change the color of other
substances.
Reflected light color
–Magenta
–Yellow
–Cyan
• Magenta + Yellow + Cyan = Black
Computer Settings
• pixel = dot = 3 numbers to assign the color (0-256)
• Red, Green, Blue = RGB
– ex: (0, 0, 0) = black
• 256 x 256 x 256 = 16,777,216 *possible different colors
The Eye
• Lens = Tiny muscles around the eye change the
•
•
shape of the eye to focus the image when light
passes through.
Iris = The colored part of the eye that controls
the amount of light entering the eye.
Retina = A membrane lining the inside of the
back of the eye composed of light sensitive
receptors that are stimulated by the different
wavelengths of light that makeup the image.
The Retina
• Rods = Rod-shaped receptors involved in
night vision, peripheral vision (corners of
the eyes) and making out the outline of
objects.
• Cones = Cone-shaped receptors that
contain color-sensitive pigments to detect
red, blue, green and all their
combinations.
Optical Illusion
• seen images that “trick” the brain into
observing something that is not real.
Mirage
• A false image in the distance produced by the
refraction of light through air layers of different
densities.
Ex. The appearance of water in the distance
Mirage
SOUND
• a pattern of air oscillations consisting of areas
of high pressure to low pressure. Sound
consists of longitudinal (compression) wave
thus it is impossible for sound to travel in
space.
• Acoustics = the science or study of sound
• Amplitude = Loudness or Volume measured
in Decibels (dB)
Decibels (dB)
• 10 – 15 dB
• 65 dB
• 70 dB
• 90 dB
• 120 dB
whisper
(3 ft away)
normal conversation (3 ft away)
city traffic
jackhammer (10 ft away)
threshold of physical pain
• 90 dB is 2x louder than 70 dB
Frequency (Pitch)
– 20 Hz
– 100 Hz
– 500 Hz
– 5000 Hz
– 10,000 Hz
– 20,000 Hz
thunder
bass guitar
average male voice
highest note on a piano
jet turbine engine
highest human limits
• human range 20 to 20,000 hertz (best
100 to 2000) *test ???
Speed of Sound
• approx. 340 m/s or 770 mi/hr (in air)
• Calculate
• speed varies greatly based on the density of
the medium
• ex: in air factors include altitude, humidity
and temperature
Supersonic
• super = above
• sonic = sound
• motion that is faster than the speed of
sound.
Ultrasound
• Medical use of sound waves to give
internal images of the human body.
• Sonogram = Images of the baby during
pregnancy.