Let There Be Light! Professor Ludwig Von Drake

Let There Be Light!

• Professor Ludwig Von Drake• Electromagnetic spectrum song• Electromagnetic spectrum song

• Bozeman light

http://www.youtube.com/watch?v=Ay2VFGDsxac

http://www.youtube.com/watch?v=P_PVz8HrrCI

http://www.youtube.com/watch?v=I024MxO3AF0

Project Benchmark #2

Build Your InstrumentTo get full credit on this benchmark, your group must do the following:•A different type of instrument for each group member•Hand made•Can make 5 or more notes•Built and checked in ON TIME! Extra Credit Opportunities:•Able to match up your notes to the actual notes that professional instruments make (for example: C, D, F#, B♭ , etc.)•Design your instruments in an artistic way or create a theme for your instruments.

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Light is the fist of painters. There is no object so foul that

intense light will not make it beautiful. Ralph Waldo Emerson, Nature (ch. III)

LIGHT

http://www.giga-usa.com/quotes/authors/ralph_waldo_emerson_a001.htm

NATURE OF WAVES• Waves (Def.) – A wave is a disturbance that transfers energy. Light travels in waves.

• Medium – Substance through which a wave is transmitted (ex. - air, glass, water, etc.)

• Speed of Waves – Depends on the properties of the medium. Speed slows down through thicker mediums.

Waves

redwavelength

violet

Of the colors we see, red has the longest

wavelength (lowest frequency)

Violet has the shortest wavelength

(highest frequency)

Electromagnetic Spectrum

The light waves that humans SEE are only a tiny part of the EM spectrum.

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EM Spectrum: Solar Radiation

• The sun produces EM radiation of all frequencies, Radio waves and visible light can easily reach us.

• X-rays from outerspace are fortunately stopped by our atmosphere.

• Some UV rays DO ENTER our atmosphere and DAMAGE our bodies.

•Radio Waves–Longest wavelength & lowest frequency.–Used for Radio & TV transmission.

Short Wavelength Microwave

• Infrared Rays•Light rays with a longer wavelength

than the red light humans can see.•Uses: Cooking, Medicine, T.V.

remote controls


Visible Spectrum – Light humans can Visible Spectrum – Light humans can seeseeRoy G. Biv – Acronym for Roy G. Biv – Acronym for RedRed, ,

OrangeOrange, , YellowYellow, , GreenGreen, , BlueBlue, , IndigoIndigo, & , & VioletViolet..

LargestLargest toto SmallestSmallest WavelengthWavelength.

Electromagnetic SpectrumUltraviolet rays.

•Electromagnetic waves with frequencies (shorter wavelength) a bit higher than visible light

•Uses: food processing & other places to kill germ cells. (It’s how we clean safety glasses)

•Helps your body use vitamin D, but causes skin cancer!


X-RaysX-ray waves are shorter than UV

rays.Uses: Medicine – Bones absorb

x-rays; soft tissue does not. Lead absorbs X-rays. You put a

lead apron over vital organs when you receive an X-ray to protect your cells from damage.

Gamma rays•Highest frequency EM waves; Shortest wavelength. They naturally come from outer space.

•Uses: Doctors use strong doses of gamma rays (cancer treatment) to kill tumor cells.


Light modelDQ: How is light different from sound waves

1. The EM spectrum consists of radio waves, microwaves, infrared, visible light, UV, x-rays, and gamma rays

2. Radio waves have long wavelengths and relatively low frequencies (making them low energy); gamma rays have short wavelengths and high frequencies (making them high energy)

3. The speed of light in a vacuum is 3.0 x 108 m/s. Nothing can travel faster!

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Write what you KNOW about pitch

Read about pitchAdd to your written response…In YOUR OWN WORDS!Did you use many physics words (frequency, transverse wave, wave length)?

Use your RUBRIC. Do you have•Definition•Relationship (what happens to the pitch when frequency changes?)•Musical instrument example •Great detail•Picture or diagram (label pictures of high and low pitch)

Share out with a partner…partner, what score would you give this response? How can it be made better?

Edit your response until it becomes a perfect 4!

Portfolio entry #1- Pitch p109

Write what you KNOW about wavelength

Read about wavelength (Active physics p498-501)Add to your written response…In YOUR OWN WORDS!Did you use many physics words (base line, crest, trough, transverse wave, longitudinal wave, rarefaction, compression)?

Use your RUBRIC. Do you have•Definition•Relationship (what happens to the wavelength when frequency changes…the wave equation!)•Musical instrument example •Great detail•Picture or diagram (show how to measure a wavelength on both kinds of waves)



Portfolio entry #2- Wavelength p113

Investigation #5 (p530-533)Shadows

• What do you see in the picture? Why does this make a funny image?

• What do you think…Explain why the length of your shadow changes during the day. When is it longest?

• You may use a cell phone instead of the lamp provided

• Do steps 1-9 and record in your notebook. Get a stamp when finished

P114-115

Shadows

• The penumbra only gets half as much light as the umbra resulting in the shadow edge being “fuzzy” or lighter in color

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Light modelShadow: What Is It?

4. Shadows are formed by an absence of light5. Light waves travel in straight lines from a light source6. A shadow will look larger if the object is close to the light source or smaller if it moves away from the light source7. A shadow may appear fuzzy if the light source is large compared to the object creating an umbra and penumbra

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Write what you KNOW about Amplitude

Read about Amplitude (Active Physics p499)Add to your written response…In YOUR OWN WORDS!Did you use many physics words (base line, crest, trough, transverse wave, longitudinal wave)?

Use your RUBRIC. Do you have•Definition•Relationship (what happens to the volume when the amplitude changes?)•Musical instrument example•Great detail•Picture or diagram (that shows how to measure amplitude)



Portfolio entry #3- Amplitude p117

CU (p534) 1-3PtoGo (p537) 1-6CDP 27-1 Get a stamp when you are finished

Finish p115

Special effect: Strobe lights

• A strobe light produces regular flashes of light

• How could you use a strobe light in your project? (the strobe light is available for practice during lunch, and available for your project presentation IF you come in and practice during lunch)

• How could you use shadows in your presentation?

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Investigation #6 (p538-541)Reflected Light

• What do you see in the cartoon window compared to the cartoon mirror?

• What do you think?• Do steps 1-13. Record in your notebook• CU (p543) 1-3• PtoGo (p546-547) 1-7 Get a stamp when you are finished P114-

115

Sniper Reflection Lab• What do you know about the word

“reflection”? Answer all 4 questions Before You Start

• Follow all directions and answer all the questions on the handout

Get a stamp when you are finished

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Light Model: Reflection8. A reflection happens when light rays bounce off a shiny surface. 9. The light path can be determined by drawing an imaginary line (the normal) to the mirrored surface. 10. The angle of incidence is equal to the angle of reflection.11. The (virtual) image formed by the mirror appears behind the surface12. The image in a mirror is backwards.Bill Nye

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What’s wrong with this picture?

• How can you use this idea in your presentation?

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Reflection: Flat Mirror• When light reflects from a flat mirror, the

incoming incident angle and outgoing reflection angle are equal.Note: Angles are always measured with respect to the perpendicular (or normal) to the mirror plane.

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Reflection: Construct a Periscope• The periscope uses two mirrors so that you

can observe an object above your line of sight.

• Click here for directions to make one!

LIGHT & ITS USES - Reflection

Reflection – Bouncing back of light wavesRegular reflection – A mirror’s

smooth surface scatters light very little. Images are clear & exact.

Diffuse reflection – Reflected light is scattered due to an irregular surface (think of crumpled foil).

FinishSniper LabCU (p543) 1-3PtoGo (p546-547) 1-7 Get a stamp when you finish

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Write what you KNOW about (sound wave) Interference

Read about (sound wave) Interference (Active Physics p847)Add to your written response…In YOUR OWN WORDS!Did you use many physics words (constructive and destructive)

Use your RUBRIC. Do you have•Definition•Relationship (what happens to the amplitude when two waves meet?)•Musical instrument example•Great detail•Picture or diagram (demonstrate how two waves combine)



Portfolio entry #4- Interference p123

Investigation #7 (p548)

• What do you see in the cartoon?• How do you think these images are

made?• How could you use a curved mirror in

your sound and light show?

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Reflection: Convex Mirror • A convex mirror is bent outwards and “distorts”

the image.• The reflection always appears upright (virtual

image) and is smaller.

p125

Reflection: Convex Mirror Application

• Because images always appear smaller in a convex mirror, a larger “field of view” is possible.

• Such mirrors are used for car side-view mirrors and surveillance mirrors in stores.

• Do you understand why car mirrors have the warning given in the cartoon?

Reflection: Concave Mirror • A concave mirror is bent inwards and also “distorts” the image.

• When an object is outside the focus of a concave mirror, the reflection appears upside-down (real image).

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Reflection: Concave Mirror (Inside Focus)

• When an object is inside the focus of a concave mirror, the reflection appears upright (virtual image).

• Try this with a spoon!

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Lenses: Convex and Concave

A convex glass lens uses refraction to bend light inwards (converging), whereas a concave lens bends light outwards (diverging).

In a convex lens, parallel light rays can be bent to a focal point.

Convex Lens Concave Lens

Focal Point

OBJECT

IMAGE

Your EYE

Convex LensA convex lens curves outward; “is rounded”. Light passing through a convex lens is bent inward, or made to converge.

Convex Lens

Concave Lens

A concave lens is curved inward (caves in). Light passing through a concave lens bends outward, or diverges. Concave lenses are generally prescribed for myopic,myopic, or near-sighted, people.

Project Benchmark #3Wave Property

How the instrument demonstrates the property

How to change the property on the instrument

Pitch*also known as?

frequency

Wind Instruments

Pan flute

Percussion Instruments

String Instruments

Brass Instruments

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Benchmark #3

Wave PropertyHow the instrument demonstrates the property



frequency

Wind Instruments

Pan flute

the length of each pipe is different. The length of the pipe determines the frequency, or pitch. A short pipe is a high pitch, a long pipe is a low pitch.


String Instruments

Brass Instruments

Benchmark #3Wave Property




frequency

Wind Instruments

flute

when your fingers plug the hole(s) on a flute, you change the length of the pipe. The length of the pipe determines the frequency, or pitch. A short pipe is a high pitch, a long pipe is a low pitch.


drums each drum plays a different note (pitch) because the drums are different sizes. The distance (either height or diameter) determines the pitch. A large drum has a low pitch, a small drum has a high pitch.

String Instruments

Brass Instruments





frequency

Wind Instruments

flute

when your fingers plug the hole(s) on a flute, you change the length of the pipe. The length of the pipe determines the frequency, or pitch. A short pipe is a high pitch, a long pipe is a low pitch.



String Instruments

Guitar

A guitar changes pitch by changing the length of the strings (when you press the string against the fret) A long string produces a low pitch, a short string produces a high pitch.

Brass Instruments





frequency

Wind Instruments

Pan flute

the length of each pipe is different. The length of the pipe determines the frequency, or pitch. A short pipe is a high pitch, a long pipe is a low pitch.



String Instruments

Guitar

A guitar changes pitch by changing the length of the strings (when you press the string against the fret) A long string produces a low pitch, a short string produces a high pitch.

Brass Instruments

Horn/trombone

A horn changes pitch when you change the length of the tube. A longer pipe produces a low pitch, a shorter pipe produces a high pitch.

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Write what you KNOW about ____________

Read about _____________( Resonance CP p521-522)(Doppler AP p44-45)Add to your written response…In YOUR OWN WORDS!Did you use many physics words ?

Use your RUBRIC. Do you have•Definition•Relationship (what happens to the ______ when ________?)•Musical instrument example •Great detail•Picture or diagram (label to demonstrate the connection to your word)


Edit your response until it becomes a perfect 4! Get a stamp

Portfolio entry #5- Resonance or Doppler Effect p124

Another Sound Quiz Tomorrow!


To get full credit for this benchmark, you must do the following:•Have a set pattern of music for your group.•Have at least 6 notes played in the composition.•Plan out an entertaining presentation for this song/melody•Write out your plans here ON TIME!Extra Credit Opportunities:•Impressive and original (made by your group) musical score.•Use the music ideas of playing loudly (forte) and softly (piano) to make a message.•Learn and play a traditional song from another culture.

p129

Write what you KNOW about Shadows

Read about Shadows (AP p533-534)Add to your written response.. In YOUR OWN WORDS!Did you use many physics words (light source, object, light rays, umbra, penumbra)?

Use your RUBRIC. Do you have•Definition•Relationship (position of the object to the light source and the type of shadow produced)•Presentation example (how could you demonstrate shadows?)•Great detail•Picture or diagram (show how shadows are formed)



Portfolio entry #6- Shadow p127

Write what you KNOW about Reflection

Read about Reflection (AP page 541-543)Add to your written response…In YOUR OWN WORDS!Did you use many physics words (plane/flat mirror, convex mirror, concave mirror)?

Use your RUBRIC. Do you have•Definition•Relationship (angle of incidence, normal, angle of reflecton)•Presentation example (how could you demonstrate reflection?)•Great detail•Picture or diagram



Portfolio Entry # 7 - Reflection p128

Spring - Summer-

Winter - Fall -

How will we use these effects in our presentation?

Optical Tools• Lenses • Eyeglasses • Microscope• Camera• Kaleidoscope• Binoculars

• Flashlight• Light boxes• Telescope• Prism• Spectroscope• Mirror

Coin Under the Cup

• Disappearing penny

Refraction: “Tricks” on our Eyes

Due to refraction of light from the water to the air, the fish appears closer to the surface than it actually is!Have you seen this phenomenon before? Where?

Figure from Niculescu

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Draw the light rays (include the normal

and angles)

Investigation #8 Refraction

• Active Physics Invest#8 (p558-560)

• Steps 1-10 • Turn in laser pointer

and get another stamp when finished

• Finish CDP and get stamps

Name Angle of incidence

Angle of refraction

Angle of reflection

304560? You decide

P130-132

Investigation #8

• The angle of incidence is larger than the angle refraction when light travels from air (less dense) to plastic (more dense)

p133

Light is bent towardsthe normal when thespeed of the new medium is lower.

Light is bent away fromthe normal in the opposite case.

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Light model:Laws of

Refraction13. Light is bent bent when it travels from one medium to another of a different density.different density.14. The law of refraction- Snell’s Law(1621)

– When the light passes through a denser medium, the light is bent toward the normal, because the light slows down (velocity decreases).

– When light passes through a less dense medium the light is bent away from the normal because the light speeds up.

p117

Draw the light rays (include the normal

and angles)

Refraction:

Air/Glass Boundary

Light “bends” or refracts between different types of material (due to slower speed in denser materials).

It is bent closer to the perpendicular (normal) in denser materials (water, glass).

Can you draw the path of a light ray from air through a piece of glass? Through water?

Denser Material

Critical angleWhen do

light rays reflect, and when do they refract?

The critical angle depends on the density of the medium

Dispersion: “Spreading” of Visible Light

When light is refracted, blue light bends more than red.

Refraction therefore causes light to “spread” or disperse into its colors, just as you see when sunlight hits a prism.

Remember: LIGHT RAYS DO NOT CURVE(They change direction)

Figure from Cutnell & Johnson

Figure from Halliday

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Refraction of Light

• Refraction – Bending of light due to a change in speed from one medium to another. – Index of Refraction – Amount (measure of an angle) by which a material refracts light.

– Prisms – Glass that bends light. Light is broken out into different colors because each frequency is bent at a different angle.

– Bill Nye

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Reflection vs. RefractionTrapping the Light

Fantastic.• Steps 1-4 together• Finish all parts of the

lab with your group

• Do CU (p562) 1-3• Get stamps when

finished

P133

Mirage Tank Demo

1.) Describe what happens to the beam before adding sugar.2.) Describe what happens to the beam after the sugar dissolves.3.) Why does this happen?4.) Describe what happens to the beam after the sugar is mixed into the water.5.) How is a mirage formed?6.) Describe a mirage you have seen outside (or in the movies)

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Write what you KNOW about Refraction

Read about Refraction (Active Physics p561-562)Add to your written response…In YOUR OWN WORDS!Did you use many physics words (density, speed, medium)?

Use your RUBRIC. Do you have•Definition•Relationship (angle of incidence, angle of refraction, snell’s law)•Presentation example (how could you demonstrate refraction?)•Great detail•Picture or diagram



Portfolio Entry # 8 - Refraction

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Reflection vs.

Refraction•PtoGo (p565) 1-4/CU (p562) 1-3 Stamp!•Benchmark #5 (front side only this week)

•Light Quiz Friday!

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P136

Project Checkpoint

• Musical instrument

• Play a song • 2 minute

presentation• You may have

back-up music• 2 light effects

• Poster• 5 sound principles• 5 light principles

TitleTeam members names

5 SOUND principlesDescribe and represent them

here

Evidence of student learning Pictures and diagrams of student project

5 LIGHT principlesDescribe and represent them here

.

Benchmark #6

Best Song EverAlex Vasilenko, Alex Shylo

SOUND principles

Evidence of student learning Pictures and diagrams of student project

LIGHT principles

.

Pitch: Our instruments each represent different levels of pitch. For example, the shoe-box the six marks have different pitch.

Volume: The drum boxes make louder noise when got bigger. This way the volume of the sound changes.

Vibrations: are a rapid back-and-forth movement. All sounds make vibrations, so our instruments also make vibrations.

Wave Diffractions: when waves hit an obstacle they will spread out. That is show in this image >.

Harmonics: When a object vibrates it propagates sound waves of a certain frequency. This frequency, in turn, sets in motion frequency waves called harmonics.

Shadow: An area that is not covered by light, mostly blocked by an object.

Color: is the visual perceptual property corresponding in humans to the categories called red, green, blue and others

Reflections: When light its something and bounces off. Not all objects reflect light, some do more then others.


Light Wave Effect How could it be used?

What materials would you need to do this idea?

Reflection

Describe it using Physics

Light Wave Property Chart

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Light Quiz #1• Turn in quiz when finished• Finish notebook pages• Work on project• Extra credit: Ch 29 focus notes due

monday

RAINBOWS - HOW DO THEY HAPPEN?

1.) What atmospheric events combine to make a rainbow?2.) How is a rainbow made?3.) What would a rainbow look like if you were in a helicopter (and there was no earth in the picture)?4. How do you make a double rainbow? What happens to the colors?

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Dispersion: Rainbow

White light is refracted inside raindrops and spreads to form the rainbow colors: roy g biv

Then the light reflects forward and refracts more as it passes out of the raindrop

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Why is the sky blue?1.) Explain why the sky is blue (what do the air molecules do to different wavelengths of light?2.) Why are sunsets red (instead of blue)?3.) How can astronomers use this information when they look at distant planets?

p138

• Transparent Objects: – All light gets transmitted through (no scattering).– Color transmitted is color you see. All other

colors are absorbed.• Translucent Objects:

– Some light is scattered and some is transmitted.• Opaque:

– Light is either reflected or absorbed. (mirrors count as opaque)

– Color of opaque objects is color it reflects.

Click to test your knowledge

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Transmission of Light

Light model:Color of Light

15. White light is the presence of ALL the colors of the visible spectrum. Notice the center of the Venn diagram above. Black objects absorb ALL the colors and no light is reflected back.16. Each color of light has a different frequency and wavelength (ROY G BIV)

– Bill Nye

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Mixing Colored LightWhen red, blue, and green light are projected onto a screen, the overlapping areas appear different colors. Where all the three overlap, white is produced.

RED + GREEN =YELLOWRED+ BLUE = MAGENTAGREEN + BLUE = CYANAdditive primary

colors are red, blue, and green because these colors produce the highest number of different colors.

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Complementary ColorsWhen two colors are added together to

produce white, they are called complementary colors.

YELLOW + BLUE = WHITE ( Yellow is a combination of Green + Red )

MAGENTA + GREEN = WHITE ( Magenta is a combination of Red + Blue)

CYAN + RED = WHITE ( Cyan is a combination of Green+ Blue)

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Color vision The eye has

three types of light receiving units, red, green and blue cones

Stimulation of Cones in Your Eyes

• If you stimulate only red and green cones, not blue, you see YELLOW.YELLOW.

Organization of the retina

Science Continues to Succeed!

• The genes controlling the three cone pigments have been located on specific chromosomes

Images of two different living human retinas showing the diversity of numbers of cones sensitive to different colors.

Phet:Color simulation• Use colored pencils to complete the handout

• Is Light More Like a Particle or a Wave?

P138-139

P140

p140

Get a stamp when done

Is light particles or waves?

• Can you knock over a book from your seat?• List how…

p140

Particle or wave?

Particle or wave?Diffraction is*Diffraction animation

Particle or wave?Interference is**Wave interference animation

Annotation Guide

What ideas or words grab your attention? Where does it say light is a wave or particle?

What puzzles you or makes you question what you thought you knew? or words that are unfamiliar to you (to look up)Place by things that connect to you, a text you’ve read, or something you knew already knew (video)

Circle key scientists, and dates

Wave particle duality – day 2P141-142

Wave particle duality – day 3

Turn in your paper when finished

Light Model:LIGHT & USES

17. Diffraction – Bending of waves around the edge of a barrier. New waves are formed from the original. breaks images into bands of light & dark and colors. 18. Interference from thin films creates iridescence (the color in bubbles)19. Polarized lenses reduce glare by sifting light20. LASERs = Light Amplification by Stimulated Emission of Radiation = produces light waves that are all the same frequency, phase, and direction

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LIGHT & USES: Diffraction

• A diffraction grating. Each space between the ruled grooves acts as a slit. The light bends around the edges and gets refracted.

© 2000 Microsoft Encarta

Polarized light

Write what you KNOW about color

Read about colorAdd to your written response…In YOUR OWN WORDS!Did you use many physics words (black, white, complimentary)?

Use your RUBRIC. Do you have•Definition•Relationship (between wave length and color observed)•Presentation example ( how can you use color in your presentation?)•Great detail•Picture or diagram



Portfolio Entry # 9 - Color p142

Write what you KNOW about _________

Read about __________Add to your written response…In YOUR OWN WORDS!Did you use many physics words ?

Use your RUBRIC. Do you have•Definition•Relationship •Presentation example •Great detail•Picture or diagram



Portfolio Entry # 10 – your choice(dispersion (rainbows), polarization (sunglasses), diffraction

(ultrasound/microscopy), EM Spectrum, interference (bubbles), lasers)

p144

• Portfolio #9: Color…page 142

• Portfolio #10: your choice page 144 (dispersion, polarization, diffraction, EM Spectrum, interference, lasers)

• project Benchmark 5 – finish the back side• Project Benchmark 6 - Bring materials to make posters

tomorrow• Unit Test Monday! Study your quizzes and notes. Practice

test and jeopardy on my website for review

Waves Unit TestThere are sample test problems for sound and light on my website!

SoundPropertiesLongitudinalAmplitude/volumeWavelength/pitchInterferenceMusical instrumentsWave equationPeriod/frequencyDoppler effectResonance

LightPropertiesTransverse/EM spectrumShadowsReflectionRefractionCritical angleColorDiffractionPolarization

Documents

Let There Be Light! Professor Ludwig Von Drake