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SI Waves

8 West SI

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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

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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.

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A transverse wave…..

A. B. C. D. E.

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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.

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What type of wave is represented by

picture?

A. B. C. D. E.

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A. TransverseB. LongitudinalC. SurfaceD. Seismic E. Help! I don’t

understand.

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A wave is a disturbance that transfers

A. B. C. D. E.

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A. matter.B. particles.C. energy.D. a medium.E. Help! I don’t

understand.

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What do you call the material that a wave travels through?

A. B. C. D. E.

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A. PlasmaB. SpaceC. VacuumD. MediumE. Help! I don’t

understand.

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What type of wave is

represented by the animation?

A. B. C. D. E.

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A. LongitudinalB. TransverseC. SurfaceD. SeismicE. Help! I don’t

understand.

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Transverse WaveDefine (in own Words) Example (from own life)

Picture /Graphic Representation of how this wave transfers energy

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Longitudinal WaveDefine (in own Words) Example (from own life)

Picture /Graphic Representation of how this wave transfers energy

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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

Wave Properties(continued)

• Wavelength is the distance from one crest to the crest of the next wave.

• Period is the time required for one full wavelength of a wave to pass a certain point.

• Frequency of a wave is the number of full wavelengths that pass a point in a given time interval.

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Wave Properties

• Transverse waves have the shape of a sine curve.

• Highest point of a transverse wave is a crest.

• Lowest point of a transverse wave is a trough.

• Amplitude is the greatest distance that particles are displaced from their normal resting position.

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Frequency-Period Equation

• Frequency=1/period• F=1/T• Frequency is measured

in a unit called a hertz.

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Wave Speed

• wave speed=frequency x wavelength

• v = f x λ

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In the diagram, identify the wave property “A”

A. B. C. D.

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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.

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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

1 2 3

Help! I

don’t underst

and.

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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.

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A. WavelengthB. FrequencyC. AmplitudeD. Help! I don’t

understand.

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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.

Reflection

• Reflection is the bouncing back of a wave when it meets a surface or boundary.

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Diffraction

• Diffraction is when a wave bends around an object or opening.

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Refraction

• Refraction is the bending of a wave as it passes from one medium to another medium.

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Wave Interference

• Wave interference is when several waves are in the same location and the waves combine to produce a single, new wave that is different from the original waves.

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Constructive Interference

• The result of two individual waves coming together to produce a wave of greater amplitude is called constructive interference.

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Destructive Interference

• The result of two individual waves coming together to produce a wave of lesser amplitude than the larger of the original waves is called destructive interference.

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What happens to the energy of the wave when the crest of the blue wave meets the crest of the green wave?

A. B. C. D.

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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?

a. b. c. d.

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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?

A. B. C. D.

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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?

A. B. C. D.

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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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ALIKE BUT DIFFERENT

Reflection, Refraction & Diffraction

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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)

Sound

• Sound waves are caused by vibrations, and carry energy through a medium.

• Sound waves are longitudinal waves.

• Speed of sound depends on the medium.

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Speed of Sound

• Speed of sound at room temperature is about 346 m/s.

• An increase in temperature increases the speed of sound.

• Sound waves travel faster in liquids & solids than gases.

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Energy is required to create a sound wave. Sound energy is also known as . . .

A. B. C. D. E.

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A. Elastic potential energy

B. Radiant energyC. Acoustic energyD. Thermal energyE. Help! I don’t

understand.

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How does sound transfer energy?

A. B. C. D.

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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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Sound cannot be heard in which of the following locations?

A. B. C. D. E.

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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.

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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.

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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)

Loudness determined by Intensity

• Intensity of a sound wave describes the rate at which a sound wave transmits energy through a given area of the medium.

• Loudness depends on the intensity of the sound wave.

• The greater the intensity, the louder the sound.

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Relative Intensity

• The relative intensity of sounds is found by comparing the intensity of a sound with the intensity of the quietest sound a person can hear.

• Relative intensity is measured in units called decibels.

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Pitch

• The pitch of a sound is related to the frequency of sound waves.

• High pitch correspond to a high frequency, and low pitch corresponds to a low frequency.

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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.

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As the frequency of a sound wave decreases. . . .

A. B. C. D.

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A. Pitch increases.B. Pitch decreases.C. Pitch stays the

same.D. Help! I don’t know.

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An ambulance is coming towards you. What happens to the sound waves?

A. B. C. D. E.

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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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How are loudness and intensity related?

A. B. C. D.

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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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Please copy circle and do this.

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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.

?

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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

Electromagnetic Spectrum

• Electromagnetic spectrum consist of light of all possible energies, frequencies and wavelengths.

• Ultraviolet light has higher energy and shorter wavelengths than purple light.

• X-rays has higher energy and shorter wavelengths.

• Gamma rays has the highest energy and shortest wavelengths.

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Electromagnetic Spectrum continued

• Infrared waves has wavelengths slightly longer than red light.

• Microwaves are used for cooking.

• Radio waves have the longest wavelengths.

• Radar is used to determine location.

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One characteristic of EM waves is:

A. B. C. D.

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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.

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A. Radio waves.B. Visible light waves.C. Ultraviolet wave.D. Gamma rays.E. Help! I don’t

understand.

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Which wave on the EM spectrum has the lowest frequency and longest wavelength?

A. B. C. D. E.

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A. Radio wavesB. X-raysC. Visible lightD. Ultra violetE. Help! I don’t

understand.

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Which wave on the EM spectrum has the highest frequency and shortest wavelength?

A. B. C. D. E.

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A. Radio wavesB. X-raysC. MicrowavesD. Gamma RaysE. Help! I don’t

understand.

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What is the only EM wave humans can see?

A. B. C. D. E.

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A. X-raysB. Ultra Violet raysC. Visible LightD. InfraredE. Help! I don’t

understand.

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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.

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Focused free write

• Write a paragraph describing electromagnetic waves. You have 3 minutes to write.

• 3 min to use book or notes (if needed)

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• We are learning to: identify specific examples of electromagnetic waves.

• We are looking for: identify 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

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Properties of EM Spectrum

• Electromagnetic spectrum are transverse waves.

• These waves are not mechanical.

• All of these waves travel at the speed of 300,000 km/sec.

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Visible Light

• Visible light contains all of the colors of the spectrum.

• ROY G BIV• A rainbow refracts light

to break it down into the separate colors.

• Raindrops act as prisms to separate the colors.

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_________Wave _________Wave

Choose two waves from the electromagnetic spectrum and complete the Venn diagram .

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Standing Waves

• Standing wave is when the interference of the original wave with the reflected wave causes the medium to vibrate in a stationary pattern.

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Standing Wave

• Nodes are the areas of a standing wave where there are no vibrations.

• Antinodes are areas of a standing wave where there is maximum vibration.

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We are learning to: demonstrate that vibrations produce transverse waves which move away from the original source. We are looking for: an explanation of the following:

• A medium is not required• A light is produced• A vibration is required to produce light wave (transverse wave)

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Light as a Wave

• Light travels as transverse waves.

• Light does not require a medium.

• Light waves are called electromagnetic waves.

• The wave model is supported because light can reflect, refract and diffract.

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Light as a Particle

• In the particle model, light travel in photons.

• Photons are considered particles.

• Photons don’t have mass, they are bundles of energy.

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Frequency of Light

• The amount of energy is proportional to the frequency of the corresponding electromagnetic wave.

• A photon with twice as much energy corresponds to a wave with twice the frequency is in the ultraviolet range.

• A photon with half as much energy corresponds to a wave with half as much frequency is in the infrared range.

Which type of wave is light?

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A. B. C. D.

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A. longitudinalB. transverseC. seismicD. surface

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Is light a mechanical wave?

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A. B.

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A. yesB. no

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Which travels faster, light or sound?

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A. B. C.

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A. lightB. soundC. Both light & sound

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Which theory explains how light travels?

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A. B. C. D.

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A. Particle theory.B. Wave Theory.C. Both Particle &

Wave Theories.D. Neither Particle or

Wave Theories.

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Write a paragraph describing a unique way in which light is used in

your everyday life.

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We are learning to: demonstrate transverse waves can be reflected off of a barrier.

We are looking for: how light is reflected off of a mirror:

•Law of Reflection.•Types of images:

•Real•virtual

•Types of mirrors:•Concave•Convex•Plane

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Reflection and Color

• Reflection occurs as light hits a barrier and bounces off of the barrier.

• The incidence ray is the incoming light waves.

• The reflected ray is the light waves that bounce off of the barrier.

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Reflection (continued)

• The angle of incidence is defined by the angle between the normal and the incidence ray.

• The angle of reflection is defined by the angle between the normal and the reflected ray.

• The law of reflection states that the angle of incidence is always equal to the angle of reflection.

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Types of Reflection

• Smooth reflection occurs when the light waves hit a smooth surface.

• Diffuse reflection occurs when the light waves hit a rough surface and the light waves are scattered.

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Types of Mirrors

• Concave mirrors are mirrors that curve inward. These type of mirrors can produce virtual & real images.

• Convex mirrors are mirrors that bulge outward. These type of mirrors can produce virtual images.

• Plane mirrors produce virtual images.

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Type of Images

• Real images are inverted images formed where rays of light meet.

• Virtual images are upright images formed where rays of light appear to meet or come from.

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Reflection Lab

• Complete the reflection lab using the light stations.

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We are learning to: demonstrate how light can be refracted as it goes through different mediums.

We are looking for: how light is refracted as it changes speed as it goes through different mediums.•Convex lens•Concave lens•prisms

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Refraction

• Refraction happens when light waves changes speed as it goes through different mediums.

• As light waves change speed the waves bend.

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Effects of Refraction

• Refraction makes objects appear to be in different positions.

• Refractions in the atmosphere creates mirages.

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Lenses

• A lens is a curved piece of glass.

• Lenses can magnify images.

• Magnification is any change in the size of an image compared with the size of the object.

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Type of Lenses

• Converging lens bends the light inward that produces a virtual or real image. (convex lens)

• Diverging lens bends the light outward and can produce only a virtual image. (concave lens)

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What causes light to refract?

Speed ch

anges

Medium ch

anges

Both A

and B

Help, I

need h...

11%

0%

78%

11%

A. Speed changesB. Medium changesC. Both A and BD. Help, I need help!

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Which type of lens is used to focus light to one point?

Concave

lens

Convex lens

Prism

Help, I

need h...

18%

0%

18%

65%A. Concave lensB. Convex lensC. Prism D. Help, I need help!

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Why does a straw appear to be bent in a glass of water?

Refracti

on

Reflection

Diff

raction

Help, I

need h...

100%

0%0%0%

A. Refraction B. Reflection C. Diffraction D. Help, I need help!

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Free Write

• Using your book as a source of information, explain how lenses can be used to correct nearsightedness and farsightedness.

Colors of the Visible Spectrum

• Red has the longest wavelength.

• Violet has the shortest wavelength.

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Colors are Reflected Light

• The color we see is the light being reflected from the object.

• Additive primary colors are red, green & blue.

• Subtractive primary colors are yellow, cyan and magenta.

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Colors and Pigments

• If all colors are reflected, you see white light.

• If all colors are absorbed, you see black.