- What Are Waves? Waves and Energy A wave is a disturbance that transfers energy from place to...
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- What Are Waves? Waves and Energy A wave is a disturbance that transfers energy from place to place. Waves travel through water (or medium, but they do not carry the water (or the duck) (the object or medium) with them. The material through which a wave travels is through a medium. Gases (air), solids, and liquids all act as mediums.
- What Are Waves? Waves and Energy A wave is a disturbance that transfers energy from place to place. Waves travel through water (or medium, but they do
- What Are Waves? Waves and Energy A wave is a disturbance that
transfers energy from place to place. Waves travel through water
(or medium, but they do not carry the water (or the duck) (the
object or medium) with them. The material through which a wave
travels is through a medium. Gases (air), solids, and liquids all
act as mediums.
Slide 2
How do Waves Transfer Energy? Mechanical waves, not
electromagnetic waves, travel through a medium. Sound waves are
mechanical waves. Waves travel through a medium, but they dont
carry the medium with them. For instance, when the wave passes, the
duck and the water return to where they started. Think of yourself
on a raft. If you had not way to propel the raft (oars); youd
remain in the same spot. Electromagnetic waves do not require a
medium
Slide 3
Using what you know, complete the Venn Diagram comparing
Mechanical Waves and Electromagnetic Waves Mechanical
WavesElectromagnetic Waves
Slide 4
What causes waves? Vibration a repeated back-and-forth or
up-and-down motion. Mechanical waves are produced when a source of
energy causes a medium to vibrate. Energy is always required to
make a wave.
Slide 5
Types of Waves Transverse (across) moves at a right angle to
the source of the energy. The highest point is called the crest The
lowest point is called the trough Exactly in between the high and
the low point is known as its resting point. Amplitude is the
maximum distance that the particles of the medium carrying the wave
move away from their rest positions. It is the amount of energy a
sound wave carries. Wavelength the distance between two
correspoinding parts of a wave. Frequency The number of complete
waves that pass a given point in a certain amount of time. Measured
in Hertz
Slide 6
- What Are Waves? Transverse Waves Waves that move through the
medium at right angles to the direction in which the waves travel
are called transverse waves.
Slide 7
- What Are Waves? Longitudinal Waves Longitudinal waves move
the medium parallel to the direction in which the waves travel.
Sound is carried through longitudinal waves.
Slide 8
All Waves have amplitude, wavelength and frequency Amplitude is
the maximum distance that the particles of the medium carrying the
wave move away from their rest positions. It is the amount of
energy a sound wave carries. Wavelength the distance between two
correspoinding parts of a wave. Frequency The umber of complete
waves that pass a given point in a certain amount of time. Measured
in Hertz (Hz). An example of Hertz is : If two waves pass you every
second, then the frequency of the wave is 2 per second, or
2Hz.
Slide 9
- Properties of Waves Amplitude, Wavelength, and Frequency The
basic properties of all waves are amplitude, wavelength, and
frequency. amplitude
Slide 10
What is happening to this wave? The energy is increasing
because the frequency is increasing. As frequency increases, pitch
gets higher. Below is an example of frequency increasing.
Slide 11
Waves Quiz Which set of waves is longitudinal? Type M for top,
A for bottom. Which set of waves is transverse? Type M for top, A
for bottom. Where is the crest on the top wave? Where is
compression occurring? Where is rarefaction occurring? Where is the
trough? Where is the amplitude? Where is the waves resting point?
Which wave represents wave lengths?
Slide 12
- Properties of Waves Wave Quiz Use your responders to answer
the questions at the front of the room. Do not press select until
you have typed in all 9 answers. U P L I T D
Slide 13
Calculating Frequency The speed of a wave on a rope is 50 cm/s
and its wavelength is 10 cm. What is the waves frequency? Plan and
Solve What quantity are you trying to calculate? The frequency of a
wave = __ Hz What formula contains the given quantities and the
unknown quantity? Frequency = Speed/Wavelength Perform the
calculation. Frequency = Speed/Wavelength = 50 cm/s/10 cm Frequency
= 5/s = 5 Hz - Properties of Waves
Slide 14
Calculating Frequency The speed of a wave on a rope is 50 cm/s
and its wavelength is 10 cm. What is the waves frequency? Look Back
and Check Does your answer make sense? The wave speed is 50 cm per
second. Because the distance from crest to crest is 10 cm, five
crests will pass a point every second. - Properties of Waves
Slide 15
Interactions of Waves Reflection, Refraction, Diffraction
Reflection When a wave hits a surface through which it cant pass.
This is called a reflection. The law of reflection states that the
angle of incidence equals the angle of reflection. Refraction The
bending of waves due to a change in speed. When a wave enters a new
medium at an angle, one side of the wave changes speed before the
other side, causing the wave to bend. Bending occurs because the
two sides of the wave travel at different speeds. Diffraction When
a wave moves around a barrier or through an opening in a barrier
and it spreads out.
Slide 16
When waves hit a surface, they move 3 ways, through reflection,
refraction and diffraction Reflection The Law of Reflection: The
angle of incidence equals the angle of reflection. All types of
waves are reflected. You can see your face in a mirror because
light waves from your face are reflected back from the mirrors
shiny surface. Refraction When a wave enters a new medium at an
angle, one side of the wave changes speed before the other side,
causing the wave to bend. The bending of waves due to a change in
speed is refraction.
Slide 17
- Interactions of Waves The Third Way: Diffraction When a wave
moves around a barrier or through an opening in a barrier, it bends
and spreads out.
Slide 18
- Interactions of Waves Interference the interaction between
waves that meet. The interference that occurs when waves combine to
make a wave with a larger amplitude is called constructive
interference. The interference that occurs when waves combine to
make a wave with a smaller amplitude is called destructive
interference. More about diffraction:
Slide 19
Standing Wave If you tie a rope to a doorknob and continuously
shake the free end, waves will come back (reflect). It can make the
wave look like its standing still. See next slide
Slide 20
- Interactions of Waves Standing Waves If the incoming wave and
a reflected wave have just the right frequency, they produce a
combined wave that appears to be standing still.
Slide 21
QuestionAnswer Answer the Questions Below Answer the questions
below: How are waves reflected? What is refraction? When does
diffraction occur? What is a standing wave? - Interactions of
Waves
Slide 22
- Seismic Waves Types of Seismic Waves Seismic waves include P
waves, S waves, and surface waves.
Slide 23
Motion of a Tsunami This graph shows the rate at which a
tsunami moves across the Pacific Ocean. Use the data plotted on the
graph to answer the following questions. - Seismic Waves
Slide 24
Motion of a Tsunami Reading Graphs: What two variables are
plotted on the graph? - Seismic Waves
Slide 25
Types of Seismic Waves Earthquakes that occur underwater, like
the one off the coast of Chile in 1960, can produce huge surface
waves on the ocean called tsunamis.
Slide 26
Waves Longitudinal All have frequency, amplitude and wavelength
can be Transverse can be contain
CrestsRarefactionsTroughsCompressions
Slide 27
Table of Contents The Nature of Sound Properties of Sound Music
How You Hear Sound Using Sound Sound Video:
http://science.howstuffworks.com/29406-
assignment-discovery-electromagnetic-waves- and-light-video.htm
Play Discovery Sound Video Here
Slide 28
- The Nature of Sound Sound Waves Sound is a disturbance
(vibration) that travels through a medium as a longitudinal (move
the medium parallel to the source) wave. As a gong vibrates, it
creates sound waves that travel through the air.
Slide 29
How Sound Travels Sounds travel through the states of matter
(medium), known as gases (air), solids, and liquids.
Slide 30
- The Nature of Sound Interactions of Sound Waves Sound waves
reflect off objects, diffract through narrow openings and around
barriers, and interfere with each other. Echo!
Slide 31
- The Nature of Sound The Speed of Sound The speed of sound
depends on the elasticity, density, and temperature of the medium
the sound travels through. Which type of medium does sound travel
the fastest according to the chart? The closer together molecules
are, the faster sound is able to travel. You can devise this from
the chart.
Slide 32
Temperature and the Speed of Sound The speed of sound in dry
air changes as the temperature changes. The graph shows data for
the speed of sound in air at temperatures from 10C to 20C. - The
Nature of Sound
Slide 33
Temperature and the Speed of Sound Reading Graphs: What is the
speed of sound in air at 10C? The speed at 10C is 325 m/s. - The
Nature of Sound
Slide 34
Temperature and the Speed of Sound Interpreting Data: Does the
speed of sound increase or decrease as temperature increases? The
speed of sound increases as air temperature increases. - The Nature
of Sound
Slide 35
Temperature and the Speed of Sound Reading Graphs: What is the
speed of sound in air at 10C? The speed at 10C is 325 m/s. - The
Nature of Sound
Slide 36
Temperature and the Speed of Sound Predicting: What might be
the speed of sound at 30C? At 30C, the speed of sound might be 349
m/s. - The Nature of Sound
Slide 37
Sound A disturbance that travels through a medium as a
longitudinal wave. Carry energy through a medium without moving the
particles of the medium along. Each particle of the medium vibrates
as the disturbance passes. When the disturbance reaches your ears,
it causes your eardrums to vibrate, and you hear sound which is
interpreted by your brain.
Slide 38
Graphic Organizer Longitudinal waves Sound has properties
Intensity DensityPitch travels as speed depends onis heard as
Frequency ElasticityTemperatureLoudness
Slide 39
Interactions of Sound waves Sound waves can reflect when they
hit a surface, and this may cause an echo Sound can diffract
through openings Sound can interfere with each other constructively
(add to the sound waves) or destructively (cancel each other
out)
Slide 40
The Speed of Sound At room temperature, sound travels at about
343 m/s, which is much faster than most jets! Sound travels at
different speeds through different mediums and at different
temperatures. Speed of sound depends on temperature, elasticity and
the density of the medium.
Slide 41
- The Nature of Sound Elasticity Elasticity is the ability of a
material to bounce back after being disturbed. You can model
elasticity by representing the particles in a medium as being held
together by springs. The more elasticity, the faster sound
travels.
Slide 42
- The Nature of Sound Density Density is how much mass there is
in a give volume. The volumes of the cubes are the same, but the
brass has more mass. The greater the density, the less sound gets
through.
Slide 43
- Properties of Sound Loudness The loudness of different sounds
is compared using a unit called the decibel (dB). Depends on two
factors: the amount of energy it takes to make the sound and the
distance from the source of the sound. Intensity is the amount of
energy a sound wave carries per second through a unit area.
Slide 44
- Properties of Sound Pitch The pitch of a sound that you hear
depends on the frequency of the sound wave. The higher the pitch,
the greater the Frequency of the wave.
Slide 45
- Properties of Sound Changing Pitch When you sing, you change
pitch using your vocal cords. Your vocal cords are located in your
voice box, or larynx.
Slide 46
Examples of what pitch looks like Medium PitchHigh Pitch (high
frequency) Lowest Pitch (low wave frequency) Lower Pitch but not
nearly as low as the wave to the left.
Slide 47
- Properties of Sound The Doppler Effect The change in
frequency of a wave as its source moves in relation to an observer
is called the Doppler effect. When a sound source moves, the
frequency of the waves changes because the motion of the source
adds to the motion of the waves.
http://www.metacafe.com/watch/961110/doppler_effect/
http://www.youtube.com/watch?v=XDqS3yOwYWc
Slide 48
- Properties of Sound The Doppler Effect When the plane travels
almost as fast as the speed of sound, the sound waves pile up in
front of the plane. This pile up is the sound barrier.
http://www.youtube.com/watch?v=eo_owZ2UK7E
http://www.youtube.com/watch?v=eo_owZ2UK7E
Slide 49
- Music Sound Quality The sound quality of musical instruments
results from blending a fundamental tone with its overtones.
Resonance also plays a role in sound quality.
Slide 50
- Music Groups of Musical Instruments There are three basic
groups of musical instruments: stringed instruments, wind
instruments, and percussion instruments.
Slide 51
Acoustics and Reverberation Acoustics the study of how sounds
interact with each other and the environment. Acoustics matter in
our classroom because the more sounds reverberate in the classroom,
the less youll be able to hear what I say. Can you think of other
places acoustics matter?
Slide 52
- How You Hear Sound The Human Ear The outer ear funnels sound
waves, the middle ear transmits the waves inward, and the inner ear
transforms sound waves into a form that travels to your brain.
Slide 53
Hearing Loss Can be caused by: Heredity Injury Infection
Exposure to loud sounds Aging
Slide 54
- Using Sound Echolocation Some animals, including bats and
dolphins, use echolocation to navigate and to find food.
Slide 55
- Using Sound Sonar A sonar device sends out ultrasound waves
and then detects the reflected waves.
Slide 56
Light and Color Reflection and Mirrors Refraction and Lenses
Seeing Light Using Light Video:
http://science.howstuffworks.com/29406-
assignment-discovery-electromagnetic-waves-
and-light-video.htm
Slide 57
- Light and Color When Light Strikes an Object When light
strikes an object, the light can be reflected, transmitted, or
absorbed. Explain difference between the three.
Slide 58
Transparent Transmits most of the light that strikes it. The
light passes right through without being scattered. Clear glass,
water and air are examples. Translucent Scatters light as it passes
through. Frosted glass, and wax paper are examples. Opaque Reflects
or absorbs all of the light that strikes it. Light cannot pass
through them. Wood, metal, and tightly woven fabrics are
opaque.
Slide 59
Light Absorption and Reflection Give objects their colors.
Slide 60
- Light and Color The Color of Objects The color of an opaque
object is the color of the light it reflects.
Slide 61
- Light and Color The Color of Objects The color of a
transparent or translucent object is the color of the light it
transmits.
Slide 62
- Light and Color Combining Colors As pigments are added
together, fewer colors of light are reflected and more are
absorbed.
Slide 63
- Reflection and Mirrors Reflection of Light Rays The two ways
in which a surface can reflect light are regular reflection and
diffuse reflection.
Slide 64
- Reflection and Mirrors Concave Mirrors A mirror with a
surface that curves inward like the inside of a bowl is a concave
mirror.
Slide 65
- Reflection and Mirrors Concave Mirrors Ray diagrams show
where an image forms and the size of the image. The steps below
show how to draw a ray diagram.
Slide 66
- Reflection and Mirrors Concave Mirrors Concave mirrors can
form either virtual images or real images.
Slide 67
- Reflection and Mirrors Convex Mirrors A mirror with a surface
that curves outward is called a convex mirror.
Slide 68
Complete the diagram below Concave MirrorConvex Mirror -
Reflection and Mirrors
Slide 69
- Refraction and Lenses Refraction of Light When light rays
enter a medium at an angle, the change in speed causes the rays to
bend or change direction.
Slide 70
Refraction When sunlight passes through a prism, rays are bent,
or refracted Prism: separates the colors of light (dispersion)
rainbows are caused by refraction in the atmosphere
Slide 71
Bending Light The index of refraction of a medium is a measure
of how much light bends as it travels from air into the medium. The
table shows the index of refraction of some common mediums. -
Refraction and Lenses
Slide 72
Bending Light Interpreting Data: Which medium causes the
greatest change in the direction of a light ray? Diamond causes the
greatest change in the direction of a light ray traveling from air.
- Refraction and Lenses
Slide 73
Bending Light Interpreting Data: According to the table, which
tends to bend light more: solids or liquids? According to the
graph, most solids bend light more than liquids do (quartz is an
exception). - Refraction and Lenses
Slide 74
Bending Light Predicting: Would you expect light to bend if it
entered corn oil at an angle after traveling through glycerol?
Explain. You would not expect light to bend if it entered corn oil
at an angle after traveling through glycerol, because corn oil and
glycerol have the same value for the index of refraction. -
Refraction and Lenses
Slide 75
When light passes through water Waves are refracted and bends
so it looks like objects you put in the water bends because light
slows down. http://www.bing.com/ videos/search?q=stev
e+spangler+refractio n&FORM=VIRE1#vie w=detail&mid=1C66
ADFAEEB1970FCF11 1C66ADFAEEB1970 FCF11 http://www.bing.com/
videos/search?q=stev e+spangler+refractio n&FORM=VIRE1#vie
w=detail&mid=1C66 ADFAEEB1970FCF11 1C66ADFAEEB1970 FCF11
WATER
Slide 76
- Refraction and Lenses Lenses A lens is a curved piece of
glass or other transparent material.
Slide 77
- Refraction and Lenses Lenses An objects position relative to
the focal point determines whether a convex lens forms a real image
or a virtual image.
Slide 78
- Refraction and Lenses Lenses A concave lens can produce only
virtual images because parallel light rays passing through the lens
never meet.
Slide 79
- Seeing LightVision Know the parts of the eye and their
functions. http://www.youtube.com/watch?v=gvozcv8pS3c
http://www.youtube.com/watch?v=gvozcv8pS3c Pages 631 and 632 of you
text draw the eyeball, the functions of what you have labeled, and
draw a schematic of what happens when light hits your eye (p 630)
Retina is like a screen on a camera. The part of the eye that
absorbs visible light waves with the highest frequencies is: blue
cones.
Slide 80
- Seeing Light What happens when light enters the eye and
passes through the lens? The light undergoes REFRACTION and forms
an image on the retina.
Slide 81
How You See Objects Light enters the eye. Light focuses on the
retina. An image forms. Rods and cones send signals to the brain. -
Seeing Light How do we see?
Slide 82
- Using Light Optical Instruments A telescope forms enlarged
images of distant objects. Telescopes use lenses or mirrors to
collect and focus light from distant objects.
Slide 83
- Using Light Optical Instruments A microscope uses a
combination of lenses to produce and magnify an image.
Slide 84
- Using Light Optical Instruments The lens of the camera
focuses light to form a real, upside-down image on film in the back
of the camera.
Slide 85
- Using Light Lasers Laser light consists of light waves that
all have the same wavelength, or color. The waves are coherent, or
in step.
Slide 86
- Using Light Optical Fibers The floodlight in the swimming
pool gives off light rays that travel to the surface. If the angle
of incidence is great enough, a light ray is completely reflected
back into the water. This complete reflection of light by the
inside surface of a medium is called total internal
reflection.
Slide 87
- Using Light Optical Fibers Optical fibers can carry a laser
beam for long distances because the beam stays totally inside the
fiber as it travels.
Slide 88
Graphic Organizer Virtual Type of Mirror Effect on Light Rays
Type of Image Type of lens Effect on Light Rays Type of Image
PlaneRegular reflection Real or virtual ConvexSpread out Convex
Virtual ConcaveConverge Virtual ConvergeReal or virtual
ConcaveSpread out
Slide 89
Table of Contents The Nature of Electromagnetic Waves Waves of
the Electromagnetic Spectrum Producing Visible Light Wireless
Communication
Slide 90
The Nature of Electromagnetic Waves Electromagnetic Waves
Believe it or not, you are being showered all the time, not by rain
but by waves.
Slide 91
The Nature of Electromagnetic Waves What Is an Electromagnetic
Wave? An electromagnetic wave consists of vibrating electric and
magnetic fields that move through space at the speed of light.
Slide 92
The Nature of Electromagnetic Waves Models of Electromagnetic
Waves Many properties of electromagnetic waves can be explained by
a wave model. Only some light waves pass through a polarizing
filter. The light that passes through vibrates in only one
direction and is called polarized light.
Slide 93
Waves of the Electromagnetic Spectrum What Is the
Electromagnetic Spectrum? The electromagnetic spectrum is the
complete range of electromagnetic waves placed in order of
increasing frequency. The part of the eye that absorbs visible
light waves with the highest frequencies are: blue cones.
Slide 94
Scientific Notation Frequencies of waves often are written in
scientific notation. A number in scientific notation consists of a
number between 1 and 10 that is multiplied by a power of 10. To
write 150,000 Hz in scientific notation, move the decimal point
left to make a number between 1 and 10: In this case, the number is
1.5. The power of 10 is the number of spaces you moved the decimal
point. In this case, it moved 5 places: 150,000 Hz = 1.5 X 10 5 Hz
Waves of the Electromagnetic Spectrum
Slide 95
Scientific Notation Practice Problem A radio wave has a
frequency of 5,000,000 Hz. Write this number in scientific
notation. 5.0 X 10 6 Hz Waves of the Electromagnetic Spectrum
Slide 96
Graphic Organizer Magnetic fields Electromagnetic waves consist
of travel at the speed of have different Electric fieldsWavelengths
Light Frequencies
Slide 97
Electromagnetic Waves Electromagnetic waves are all around
youin your home, your neighborhood, and your town. Waves of the
Electromagnetic Spectrum
Slide 98
The Electromagnetic Spectrum Q. Which electromagnetic waves
have the shortest wavelength? A. Gamma rays have the shortest
wavelength. Q. Which electromagnetic waves have the lowest
frequency? A. Radio waves have the lowest frequency. Waves of the
Electromagnetic Spectrum
Slide 99
Producing Visible Light Incandescent Lights An incandescent
light is a light bulb that glows when a filament inside it gets
white hot.
Slide 100
Producing Visible Light Neon Lights A neon light is a sealed
glass tube that contains neon gas.
Slide 101
Feature Comparing and Contrasting Glass Ordinary Light Bulb
Tungsten- Halogen FluorescentVaporNeon Bulb Material Hot/Cool
Makeup Efficiency Quartz Glass HotVery HotCool Tungsten filament
and nitrogen gas and argon gas inside Has tungsten filament and a
halogen gas inside A gas and a powder coating inside Has neon or
argon gas and solid sodium or mercury inside Has neon gas inside
Not efficient More efficient than ordinary bulb Very efficient
Producing Visible Light Glass Cool Very efficient
Slide 102
Wireless Communication Radio and Television In AM
transmissions, the amplitude of a radio wave is changed. In FM
transmissions, the frequency is changed.
Slide 103
Comparing Frequencies The table shows the ranges of radio
broadcast frequencies used for AM radio, UHF television, FM radio,
and VHF television. Wireless Communication
Slide 104
Comparing Frequencies Interpreting Data: In the table, what
units of measurement are used for frequency? Kilohertz (kHz) and
megahertz (MHz) Wireless Communication
Slide 105
Comparing Frequencies Interpreting Data: Which type of
broadcast shown in the table uses the highest frequency radio
waves? Which uses the lowest frequency waves? UHF television uses
the highest frequency radio waves, and AM radio broadcast uses the
lowest frequency radio waves. Wireless Communication
Slide 106
Comparing Frequencies Calculating: Which type of broadcast uses
waves with the shortest wavelength? UHF television uses waves with
the highest frequency and therefore the shortest wavelength.
Wireless Communication
Slide 107
Comparing Frequencies Inferring: A broadcast uses a frequency
of 100 MHz. Can you tell from this data if it is a television or
radio program? Explain. You cannot tell from this data if it is a
television or radio program, because VHF television and FM radio
both broadcast radio waves with a frequency of 100 MHz. Wireless
Communication
Slide 108
Wireless Communication Cellular Phone System In the cellular
phone system, cellular phones transmit and receive radio waves that
travel to the nearest tower.
Slide 109
Wireless Communication Communication Satellites In the Global
Positioning System (GPS), signals from four satellites are used to
pinpoint a location on Earth.
Slide 110
What You Know What You Learned Using Prior Knowledge 1.Cellular
phones dont use wires. 2.Radio and television signals travel
through the air. 1.The signals for radio and television programs
are carried by radio waves. 2.The signals can be transmitted by
changing either the amplitude or the frequency of the radio waves.
3.Cellular phones transmit and receive signals using microwaves.
Wireless Communication
Slide 111
Graphic Organizer Magnetic fields Electromagnetic waves consist
of travel at the speed of have different Electric fieldsWavelengths
Light Frequencies