WAVES Mechanical and Electromagnetic TEXT BOOK SOUND AND LIGHT
CHP 1-4 Images from pearsonsuccessnet.com
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CH 1 LESSON 1 WHAT ARE WAVES LEARNING OBJECTIVES: Explain what
causes mechanical waves. List and describe three types of
mechanical waves.
Slide 3
Explain what causes mechanical waves. WAVE Is a disturbance
involving the transfer of energy from place to place. Most waves
need a material to travel through (MEDIUM). Examples of Mediums
Air, Water, Solids MECHANICAL WAVES require two things: Source of
energy which creates vibrations A MEDIUM that vibrates
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List and describe three types of mechanical waves. TRANSVERSE :
A wave that vibrates at right angles to the direction in which the
wave travels (up and down). LONGITUDINAL: A wave that vibrates the
medium in the same direction in which the wave travels (back and
forth). SURFACE: Combination of transverse and longitudinal waves.
Wave passes through the water it vibrates up/down AND back/forth
this causes water molecules to move in circles.
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TRANSVERSE WAVE CREST TRHOUGH
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LONGITUDINAL COMPRESSION RAREFACTION
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SURFACE WAVE
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CHP 1 LESSON 2 PROPERTIES OF WAVES LEARNING OBJECTIVES:
Describe the basic properties of waves. Explain how a waves speed
is related to it s wavelength and frequency.
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Describe the basic properties of waves. AMPLITUDE : Is the max
height of the wave from resting position. High waves have more
energy ! WAVELENGTH : Distance between repeating parts. Crest Crest
Trough Trough Compression - Compression FREQUENCY : Number of waves
per second (Hertz). Higher frequency waves have more energy !
SPEED: How far the wave travels in a given time. Speed is affected
by medium and temperature.
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Text Book pg 12-13
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Explain how a waves speed is related to it s wavelength and
frequency. The wave speed, wavelength, and frequency are related
mathematically: Speed = Wavelength X Frequency If the medium is the
SAME, with same temp and pressure, then the speed with be the same
!
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CHP 1 LESSON 3 INTERACTIONS OF WAVES LEARNING OBJECTIVES:
Describe how reflection, refraction, and diffraction change a waves
direction.
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Describe how reflection, refraction, and diffraction change a
waves direction. REFLECTION: If a wave hits a surface and cannot
pass through, the wave bounces back. Law of Reflection states that
the angle of incidence (incoming) EQUALS the angle of
reflection.
Slide 14
Describe how reflection, refraction, and diffraction change a
waves direction. REFRACTION: Refraction is the bending of waves due
to change in speed. Waves bend when 1 side of the wave changes
speed before the other side. Waves do NOT bend if: it enters new
medium at a RIGHT angle new medium has SAME speed.
Slide 15
Describe how reflection, refraction, and diffraction change a
waves direction. DIFFRACTION : When a wave moves around a barrier
or through an opening, it bends and spreads out.
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CHP 2 LESSON 1 THE NATURE OF SOUND LEARNING OBJECTIVE: Define
sound. Identify factors that affect the speed of sound.
Slide 17
Define sound. Sound is caused by energy creating a disturbance
which vibrates a medium (gas, liquid, or solid) and travels through
LONGITUDINAL WAVES. Read page 35 in the book Explain how sound
waves form from a drumheads.
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Identify factors that affect the speed of sound. Medium
TEMPERATURE: Sound travels SLOWER at lower (colder) temps particles
move less Sound travels FASTER at higher (warmer) temps particles
move more
Slide 19
Identify factors that affect the speed of sound. Medium
STIFFNESS: Sound travels FASTER in stiffer mediums because it
compresses more quickly. faster thru solids, slower thru gases
Medium DENSITY: Sound travels SLOWER through denser materials
because particles are already very compressed.
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CHP 2 LESSON 2 PROPERTIES OF SOUND LEARNING OBJECTIVES: State
what the pitch of a sound depends on. Identify factors that affects
the loudness of a sound. Explain what causes the Doppler effect.
Tuning Fork Demonstration Video
http://www.arborsci.com/cool/top-10-
demonstrations-with-tuning-forks
Slide 21
State what the pitch of a sound depends on. PITCH depends on
the wave FREQUENCY of the sound. High frequency waves have a high
pitch (soprano singer) Low frequency waves have a low pitch (bass
singer)
Slide 22
Identify factors that affects the loudness of a sound. LOUDNESS
of a sound depends on the energy and intensity of the sound wave.
More ENERGY creates a greater AMPLITUDE which causes LOUDER SOUND !
Loudness is measured in DECIBELS (dB). Sounds over 100 dB can cause
damage to ears.
Slide 23
Explain what causes the Doppler effect. The Doppler Effect
occurs because the source causing the waves moves which changes the
frequency. The motion causes the waves to either spread OUT or get
close TOGETHER: Spread out = lower frequency Close together =
higher frequency
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CHP 3 LESSON 1 THE NATURE OF ELECTROMAGNETIC W. LEARNING
OBJECTIVES: State what an electromagnetic wave consists of. Draw an
electromagnetic wave.
Slide 25
State what an electromagnetic wave consists of. Electromagnetic
waves are TRANSVERSE waves made up of vibrating ELECTRIC and
MAGNETIC fields. Electromagnetic waves transfer energy called
ELECTROMAGNETIC RADIATION. They DO NOT require a medium, so they
can transfer waves through a vacuum or empty space. They move at
the SPEED OF LIGHT (300,000km/s)
Slide 26
Draw an electromagnetic wave.
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CHP 3 LESSON 2 WAVES OF ELECTROMAGNETIC SPECTRUM LEARNING
OBJECTIVES: Explain how electromagnetic waves are alike and how
they are different. Describe the waves that make up the
electromagnetic spectrum.
Slide 28
Explain how electromagnetic waves are alike and how they are
different. ALL electromagnetic waves travel at the same speed in a
vacuum (light speed). Electromagnetic waves have DIFFERENT
wavelengths and frequencies ! Long wavelength=low frequency Short
wavelengths=high frequency
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Slide 30
CHP 4 LESSON 1 LIGHT AND COLOR LEARNING OBJECTIVES: Describe
what determines the color of an opaque, transparent, or translucent
object. Explain how mixing pigments is different from mixing
light.
Slide 31
What happens to light when it strikes an opaque, transparent,
or translucent object. TRANSPARENT : Light passes through the
material without being scattered. (water, air, clear glass)
TRANSLUCENT : The material scatters the light as it passes through.
(wax paper, frosted glass, fog) OPAQUE: The material reflects or
absorbs all of the light (does not pass through).
Slide 32
Describe what determines the color of an opaque object. The
color of an opaque object is the COLOR of the light that is
REFLECTED. Pigments absorb specific wavelengths of light, others
are then reflected off! RED LIGHT: Apple reflects red Leaves absorb
red GREEN LIGHT : Apple absorbs green Leaves reflect green
Slide 33
Explain how mixing pigments is different from mixing light.
PRIMARY COLORS of LIGHT: Red, Blue, Green When the PRIMARY colors
of LIGHT are mixed EQUALLY, they produce WHITE LIGHT !
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WHITE LIGHT
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Explain how mixing pigments is different from mixing light.
PIGMENTS absorb specific wavelengths of light, others are then
reflected (color). PRIMARY COLORS of Pigment Yellow, Cyan, Magenta
When the PRIMARY colors of PIGMENT are mixed EQUALLY, they produce
the color BLACK !
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CHP 4 LESSON 2 AND 3 REFLECTION AND REFRACTION LEARNING
OBJECTIVES: Identify kinds of reflection. Explain why light rays
bend when they enter a medium at an angle.
Slide 37
Identify kinds of reflection. REGULAR reflection occurs when
light rays hit a smooth surface and reflect at the same angle
(mirror image). DIFFUSE reflection occurs when light rays hit
uneven surface and reflect at different angles (most objects).
Slide 38
Explain why light rays bend when they enter a medium at an
angle. When light rays enter a new MEDIUM at an angle, 1 side
changes speeds before the other side. This causes the ray to
bend.
Slide 39
Explain why light rays bend when they enter a medium at an
angle. Light travels fastest in AIR, slower in WATER, and slowest
in GLASS. Index of Refraction is a measure of how much a light ray
bends. The higher index of refraction, the greater the bend.