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Energy & Waves
8 West Science
We are learning to: identify different forms of energy We are looking for: identification of the following:
Chemical – energy stored in the bonds of atomsElectrical – energy in moving electronsMechanical – energy in motionThermal – heat energyAcoustic – sound energyNuclear – energy stored in the nucleus of an atomElectromagnetic – visible(radiant), UV rays, microwaves, etc.
Energy
• The ability to do work or cause change is called energy.
• Works is the transfer of energy.
• Two types of energy:– Kinetic energy is
energy of motion.– Potential energy is
energy of position or shape.
3
Forms of Energy
• Mechanical energy• Chemical energy• Nuclear energy• Electrical energy• Electromagnetic
energy• Thermal energy• Acoustical energy
4
What type of energy is present in a battery?
Chemical e
nergy
Electr
ical E
nergy
Mech
anical E
nergy
Solar E
nergy
I need help. I
don’t und...
0% 0% 0%0%0%
A. Chemical energyB. Electrical EnergyC. Mechanical EnergyD. Solar EnergyE. I need help. I don’t
understand.
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10
What type of energy is required to operate this device?
0% 0% 0%0%0%
A. Electrical energyB. Chemical EnergyC. Mechanical EnergyD. Thermal EnergyE. Help!
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10
What is the type of energy present in the sun?
Electr
ical
Kinetic
Chemical
Nucle
ar
I don’t
know. ..
.
0 0 000
A. ElectricalB. KineticC. ChemicalD. NuclearE. I don’t know. I need
help.
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10
What type of energy is dependent on the height of an object?
Chemical p
oten...
Elasti
c potent..
.
Grav
itational ..
.
Kinetic
I don’t
know. ..
.
0 0 000
A. Chemical potentialB. Elastic potentialC. Gravitational
potentialD. KineticE. I don’t know. I need
help.
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Concept Circle
Chemical Energy
1. Fill in three other types of energy closely relate to the energy given
2. Write a paragraph explaining the significance of each energy type and how they fit together to form a concept.
Forms of Energy
• Mechanical energy is the energy associated with the motion or position of an object.
• Thermal energy is the total energy of the particles in an object.
• Chemical energy is the potential energy stored in chemical bonds that hold chemical compounds together.
10
Forms of Energy
• Electrical energy is moving electric charges produce electricity and energy.
• Electromagnetic energy travels in waves and have both electrical & magnetic properties.
• Nuclear energy is energy stored in the nucleus of an atom and is released during nuclear reactions.
11
Forms of Energy
• Accoustical energy is energy of sound.
12
• We are learning to: describe how an object can have potential and/or kinetic energy
• We are looking for: kinetic energy (the energy of an object because of its motion) and potential energy (the energy stored by an object because of its location).
• We are learning to: explain the changing relationship between potential and kinetic energy of an object at rest or in motion
• We are looking for: As height increases, potential energy increases. As velocity increases, kinetic energy increases
Potential Energy
• Elastic potential energy is energy stored when an object is stretched or compressed.
• Gravitational potential energy is energy stored because of the height of the object’s position.
• Chemical potential energy is energy stored in the bonds between atoms.
• GPE= weight x height.• Energy is measured in
units called Joules.
15
Kinetic Energy
• Remember, kinetic energy is energy of motion.
• KE=½(mass x velocity2)• Doubling the mass,
doubles the kinetic energy.
• Double the velocity, quadruple the kinetic energy.
16
At what point does the swinging pendulum have the most kinetic energy?
A. B. C. D. E.
0 0 000
A. AB. BC. CD. DE. I don’t
understand. I need help!
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10
At what point would the swinging pendulum have the most potential energy?
A. B. C. D. E.
0 0 000
A. AB. BC. CD. DE. I don’t
understand. I need help!
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10
What is the relationship between potential and kinetic energy?
A. B. C. D. E.
0 0 000
A. There is no relationship.B. As PE increases, KE increases.C. As PE increases, KE decreases.D. As PE decreases, KE decreases.E. I don’t understand. I need help!
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10
Electricity is produced in a hydroelectric plant when moving water turns a turbine.
Which describes this energy transformation from the turning turbine to electricity?
1 2 3 4 5
0 0 000
a. kinetic energy into electric energyb. nuclear energy into electric energyc. thermal energy into electric energyd. chemical energy into electric energye. Help! I don’t understand.
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Joe Shmoe turns on a flashlight. Which of the following lists the energy transformations in the system?
A. B. C. D. E.
0 0 000
A. Electrical chemical mechanical radiant
B. Chemical electrical thermal mechanical
C. Nuclear chemical electricalD. Mechanical chemical Electrical
radiantE. I don’t understand. I need help!
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10
Concept MapCreate 5 questions about Energy on loose leaf using this graphic
organizer. Exchange with a partner and answer the questions.
ENERGY
Question
Question
Question
Question
QuestionA
AA
A
A
We are learning to: explain the law of conservation of energy.
We are looking for: how energy can change from one form to another without the loss of overall energy
We are learning to: trace energy transformations in a closed system (i.e., flashlight)
We are looking for: the ordering of how one form of energy changes (transforms) to another. (See aforementioned types of energy)
Conservation of Energy
• Law of conservation of energy states that when one form of energy is converted to another, no energy is destroyed in the process.
• According to the law of conservation of energy, energy cannot be created or destroyed.
24
We are learning to: demonstrate how waves transfer energy.
We are looking for: a disturbance or variation that
transfers energy from one point to another point in a medium.
Transverse waves- wave and medium move in direction that is perpendicular to each other
Longitudinal waves- wave and medium move in same direction
26
What are Waves?
• A wave is a disturbance that transfers energy from place to place
• Waves travel through a material called a medium.
• Waves that require a medium to travel through are called mechanical waves.
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What are Waves?
• Waves are created when a source of energy causes a medium to vibrate.
• A vibration is a repeated back-and-forth or up-and –down motion.
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Classification of Waves
• Wave are classified according to how they move.
• Types of waves:1. Transverse2. Longitudinal3. Surface
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Transverse Wave
• In transverse waves, the particles of the medium move perpendicular in the direction of the wave.
• Parts of the transverse wave:– Crest– Trough– Wavelength– Amplitude
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Longitudinal Wave
• In longitudinal waves, the particles of the wave move parallel to direction of the wave movement.
• Parts of the wave:– Compressions– Rarefactions– Wavelength
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Surface Wave
• Surface waves occur at the boundary between two mediums and are a combination of transverse and longitudinal waves.
A transverse wave…..
A. B. C. D. E.
8
16
00
3
A. Vibrates particles perpendicular to the direction of wave
B. Vibrates particles parallel to the direction of the wave
C. Vibrates both parallel and perpendicular to the direction of the wave
D. Vibrates particles in one directionE. Help! I don’t understand.
What type of wave is represented by
picture?
A. B. C. D. E.
3
22
001
A. TransverseB. LongitudinalC. SurfaceD. Seismic E. Help! I don’t
understand.
A wave is a disturbance that transfers
A. B. C. D. E.
02
0
3
22
A. matter.B. particles.C. energy.D. a medium.E. Help! I don’t
understand.
What do you call the material that a wave travels through?
A. B. C. D. E.
0 1 0
26
0
A. PlasmaB. SpaceC. VacuumD. MediumE. Help! I don’t
understand.
What type of wave is
represented by the animation?
A. B. C. D. E.
0
19
01
4
A. LongitudinalB. TransverseC. SurfaceD. SeismicE. Help! I don’t
understand.
Transverse WaveDefine (in own Words) Example (from own life)
Picture /Graphic Representation of how this wave transfers energy
Longitudinal WaveDefine (in own Words) Example (from own life)
Picture /Graphic Representation of how this wave transfers energy
We are learning to: describe the properties of waves.
We are looking for: Wavelength-distance from crest to crest (transverse wave), or from compression to compression (longitudinal wave)Frequency-number of waves that pass a given point each secondAmplitude-distance from rest position to the crest (transverse wave); measures how compressed the particles of the medium are (longitudinal wave); determines the amount of energy of each wave
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Properties of Waves
• The basic properties of waves are amplitude, wavelength, frequency, and speed.
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Amplitude
• Amplitude is the maximum distance the particles of the medium carrying the wave move away from their rest position.
• Measured from crest to resting position.
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Wavelength
• Wavelength is the distance between corresponding parts of a wave.
• Wavelength is measured from crest to crest.
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Frequency
• Frequency of a wave is the number of complete waves that pass a given point in a certain amount of time.
• Frequency is measured in hertz.
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Wave Speed
• Wave speed is how far the wave travels in one unit of time, or distance divided by time.
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Mathematical Relationship
• The speed, wavelength, and frequency of a wave are related to each other by a mathematical formula:
Speed=wavelength x frequency
In the diagram, identify the wave property “A”
A. B. C. D.
0 000
A. FrequencyB. AmplitudeC. WavelengthD. Help! I don’t understand.
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Which of the following is true about waves in the diagram?
A. B. C. D.
0 000
A. Wave X has a higher frequency than Wave Y
B. Wave X has a lower frequency than Wave Y
C. Wave X has the same frequency as Wave Y
D. Help! I don’t understand.
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Which of the waves in the picture has the greatest
amplitude?
1
2
3
A. B. C. D.
0 000
A. 1B. 2C. 3D. Help! I don’t understand.
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Which property measures the amount of energy transferred by a wave?
A. B. C. D.
0 000
A. WavelengthB. FrequencyC. AmplitudeD. Help! I don’t
understand.
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10
ALIKE BUT DIFFERENT
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We are learning to demonstrate how waves transfer energy.
We are looking for how waves interact with an object or other waves. They either:
Transmit-wave energy passes through an object.
Reflect-wave energy bounces off an object.
Refract – wave changes speed as it passes from one medium to another medium
Diffract – wave spreads out as it passes through an opening or around the edge of a barrier
Absorb-wave energy is taken in by an object they encounter.
Interference-wave energy of multiple waves is combined.
52
Reflection• Reflection happens when
waves bounce off of a barrier.• The angle of incidence is the
angle between the incoming wave and the imaginary perpendicular line.
• The angle of reflection is the angle between the reflected wave and the imaginary perpendicular line.
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Law of Reflection
• The angle of reflection is equal to the angle of incidence.
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Refraction
• Refraction occurs as the wave go between different mediums.
• The speed of a wave changes as the medium changes.
• The change in speed of the wave causes the waves to bend.
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Diffraction
• Diffraction is the bending of waves as the waves go through a small opening or around a corner.
• As the wave goes through the hole or around the corner, it spreads out and bends.
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Interference
• Interference occurs as two or more waves interact.
• Constructive interference happens when waves meet and the amplitude increases.
• Destructive interference happens when waves meet and the amplitude decreases.
What happens to the energy of the wave when the crest of the blue wave meets the crest of the green wave?
Energy
decreas
es.
Energy
incre
ases.
Energy
stays t
he same.
I don’t
get it
! Help!
0 000
A. Energy decreases.B. Energy increases.C. Energy stays the
same.D. I don’t get it! Help!
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What is it called when a wave bounces off of a barrier?
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a. b. c. d.
0% 0%0%0%
a. Refractionb. Reflectionc. Diffractiond. Help! I don’t know.
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What happens to waves as they go through an opening or around a
corner of an object?
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A. B. C. D.
0% 0%0%0%
A. They are refracted.B. They are reflected.C. They are diffracted.D. Help! I don’t know.
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As waves go through different mediums, what happens to them?
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A. B. C. D.
0% 0%0%0%
A. Waves change speed and are reflected.
B. Waves change speed and are refracted.
C. Waves change speed and are diffracted.
D. Help! I don’t know.
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10
ALIKE BUT DIFFERENT
We are learning to: demonstrate that vibrations produce longitudinal waves which move away from the original source. We are looking for: an explanation of the following:
• A medium is required (mechanical wave)• A sound is produced (acoustic energy)• A vibration is required to produce sound waves (longitudinal wave)
Properties of Sound
• Intensity of a sound wave is the amount of energy that a wave carries per second through a unit area.
• Loudness describes what you actually hear.
• A sound wave of greater intensity generally sound louder.
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Sound Loudness
• The loudness of sound is measured in decibels.
• Threshold of hearing is at 0 decibels.
• Sound louder than 120 decibels can cause pain and permanent damage.
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Frequency & Pitch
• Frequency is the number of sound waves that pass a given point in a given amount of time.
• Human hearing is between 20 Hz and 20,000 Hz.
• Ultrasound is sound waves above the normal human hearing range.
65
Frequency & Pitch
• Infrasound are sound waves that are below the normal range of human hearing.
• Pitch of a sound is a description of how high or low the sound seems to a person.
• Pitch of a sound that you hear depends on the frequency of the sound wave.
66
The Doppler Effect
• The apparent change in frequency as a wave source moves in relation to the listener is called the Doppler Effect.
• As sound source moves toward the listener, the waves reach the listener with a higher frequency.
• The pitch appears to increase because of the Doppler effect.
67
Energy is required to create a sound wave. Sound energy is also known as . . .
A. B. C. D. E.
0 0 000
A. Elastic potential energy
B. Radiant energyC. Acoustic energyD. Thermal energyE. Help! I don’t
understand.
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10
How does sound transfer energy?
A. B. C. D.
0 000
A. By vibration of a medium, producing a transverse wave.
B. By vibration of a medium, producing a longitudinal wave.
C. By vibration of a medium, producing a surface wave.
D. Help! I don’t know.
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10
Sound cannot be heard in which of the following locations?
A. B. C. D. E.
0 0 000
A. In a buildingB. Under waterC. In spaceD. In the forestE. Help! I don’t know.
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FOUR BLOCK INTERVENTION INSTRUCTIONS
1. If you have not missed any questions, start with block #2 and then complete blocks #3 and #4.
2. If you have missed 2 or more, meet with the teacher.
3. Everyone else starts in block #1 and then complete blocks #2, #3, and #4.
3. REVIEW
1. PRACTICE
4. FRONTLOAD
2. EXTENSION
A tree falls in a forest and no one is around to hear it. Is a sound produced?
Using your knowledge of sound waves, write a paragraph (6-10 sentences)explaining why or why not?
Draw a transverse wave and a longitudinal wave.
Label all of their parts.
What do you know about the electromagnetic spectrum?
Explain how a sound is produced when you beat a drum.
We are learning to: demonstrate that vibrations produce longitudinal waves which move away from the original source.
We are looking for: the identification of the properties of sound.Intensity-how much energy sound hasLoudness-our perception of intensityPitch-frequency of waves produced (highness and lowness of sound) (i.e. Doppler Effect)
Sound
• Sound is a longitudinal wave.
• Factors that affect the speed of sound:– Temperature– Elasticity– Density
Combining Sound Waves
• Timbre describes the quality of the sound you hear.
• The blending of the fundamental tone and the overtones makes up the characteristic sound quality, or timbre, of a particular sound.
75
Music
• Music is a set of tones combined in ways that are pleasing to the ear.
• Repeated change in loudness are called beats.• Types of instruments:– Strings– Brass– Woodwinds– Percussion
76
Noise
• Noise has no pleasing timbre and no identifiable pitch.
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Interference of Sound Waves
• Interference occurs when two or more sound waves interact.
• Acoustics describe how well sound can be heard in a particular room or hall.
78
As the frequency of a sound wave decreases. . . .
A. B. C. D.
0 000
A. Pitch increases.B. Pitch decreases.C. Pitch stays the
same.D. Help! I don’t know.
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10
An ambulance is coming towards you. What happens to the sound waves?
A. B. C. D. E.
0 0 000
A. Frequency decreases and pitch decreases
B. Frequency increases and pitch decreases
C. Frequency decreases and pitch increases
D. Frequency increases and pitch increases
E. Help! I don’t know.
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10
How are loudness and intensity related?
A. B. C. D.
0 000
A. The louder the sound the less the intensity
B. The louder the sound the more the intensity
C. There is no relationship between loudness and intensity
D. Help! I don’t know.
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10
Please copy circle and do this.
?
Pitch
Sound
• Fill in words that closely relates to the two words given.
• Write a paragraph explaining why you chose each word and how they fit together to form a concept.
?
83
Standing Waves
• Standing waves form as the original wave is interfered with by the reflected wave.
• The standing wave has a node and an antinode.
84
We are learning to: describe electromagnetic waves and give specific examples of several types.
We are looking for: 1. Description:-transverse waves that change between electric and magnetic fields.-waves that do not require a medium -the energy that is transferred by electromagnetic waves (electromagnetic radiation)
2. Examples of EM waves based on wavelengths and frequency:-Radio wave-longest wavelength; lowest frequency-Infrared-Visible light-Ultraviolet-x-ray-gamma rays-shortest wavelength; highest frequency
86
Electromagnetic Waves
• Electromagnetic waves are transverse waves that have some electrical properties and some magnetic properties.
• An electromagnetic wave consists of changing electric and magnetic fields.
87
Electromagnetic Radiation
• The energy that is transferred by electromagnetic waves is called electromagnetic radiation.
• All electromagnetic waves travel at the same speed: 300,000, 000 m/s.
88
Characteristics of Electromagnetic Waves
• All electromagnetic waves travel at the same speed, but they have different wavelengths and different frequencies.
• Remember:
Speed=wavelength x frequency
89
Different Wavelengths of the Electromagnetic Spectrum
In order of decreasing wavelength:
• Radio• Infrared• Visible light• Ultraviolet• X ray• Gamma ray
One characteristic of EM waves is:
A. B. C. D.
0 000
A. travels as a longitudinal wave
B. does not require a medium
C. does not travel as a transverse wave
D. I need help!!
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Which form of electromagnetic wave has the shortest wavelength and the greatest energy?
A. B. C. D. E.
0 0 000
A. Radio waves.B. Visible light waves.C. Ultraviolet wave.D. Gamma rays.E. Help! I don’t
understand.
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10
Which wave on the EM spectrum has the lowest frequency and longest wavelength?
A. B. C. D. E.
0 0 000
A. Radio wavesB. X-raysC. Visible lightD. Ultra violetE. Help! I don’t
understand.
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10
Which wave on the EM spectrum has the highest frequency and shortest wavelength?
A. B. C. D. E.
0 0 000
A. Radio wavesB. X-raysC. MicrowavesD. Gamma RaysE. Help! I don’t
understand.
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10
What is the only EM wave humans can see?
A. B. C. D. E.
0 0 000
A. X-raysB. Ultra Violet raysC. Visible LightD. InfraredE. Help! I don’t
understand.
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10
Similarities Differences
Sound Waves vs. Electromagnetic Waves
Copy the below data table in your NB.Using your prior knowledge of sound , and new knowledge of EM waves. Fill in the below table.
