Light and Optics Light and Optics 6.P.1.2 Students will explain the relationship between visible light, the electromagnetic spectrum, and sight

Light and OpticsLight and Optics6.P.1.2 Students will explain the relationship between visible light, the electromagnetic spectrum, and sight. 6.P.1.2 Students will explain the relationship between visible light, the electromagnetic spectrum, and sight.

The Blind SpotThe Blind Spot

The blind spot is the area on the retina The blind spot is the area on the retina without receptors that respond to light. without receptors that respond to light. Therefore an image that falls on this Therefore an image that falls on this

region will NOT be seen. It is in this region region will NOT be seen. It is in this region that the optic nerve exits the eye on its that the optic nerve exits the eye on its

way to the brain. way to the brain.

http://faculty.washington.edu/chudler/chvision.htmlhttp://faculty.washington.edu/chudler/chvision.html

Can you find your blind spot?Can you find your blind spot?

Let’s test it out!Let’s test it out!


ProcedureProcedure To draw the blind spot tester on a piece of paper, make a small dot on the left side separated by To draw the blind spot tester on a piece of paper, make a small dot on the left side separated by

about 6-8 inches from a small + on the right side. Close your right eye. Hold the image (or place about 6-8 inches from a small + on the right side. Close your right eye. Hold the image (or place your head from the computer monitor) about 20 inches away. With your left eye, look at the +. your head from the computer monitor) about 20 inches away. With your left eye, look at the +. Slowly bring the image (or move your head) closer while looking at the +. At a certain distance, Slowly bring the image (or move your head) closer while looking at the +. At a certain distance,

the dot will disappear from sight...this is when the dot falls on the blind spot of your retina. the dot will disappear from sight...this is when the dot falls on the blind spot of your retina. Reverse the process. Close your left eye and look at the dot with your right eye. Move the image Reverse the process. Close your left eye and look at the dot with your right eye. Move the image

slowly closer to you and the + should disappear.slowly closer to you and the + should disappear.


Did You KnowDid You Know

An octopus does not have a blind spot! The retina of the octopus is An octopus does not have a blind spot! The retina of the octopus is constructed more logically than the constructed more logically than the mammalian retina. The . The

photoreceptors in the octopus retina are located in the inner portion photoreceptors in the octopus retina are located in the inner portion of the eye and the cells that carry information to the brain are of the eye and the cells that carry information to the brain are

located in the outer portion of the retina. Therefore, the octopus located in the outer portion of the retina. Therefore, the octopus optic nerve does not interrupt any space of retina.optic nerve does not interrupt any space of retina.


Write this vocabulary in your Write this vocabulary in your ISN! ISN!

OpaqueOpaque

OpaqueOpaque:: Light can not pass Light can not pass through, thus creating a through, thus creating a shadow.shadow.

Examples:Examples: cardboard, brick, cardboard, brick, solid wood door.solid wood door.

TransparentTransparent

Transparent materialsTransparent materials: Allow : Allow almost all the light to pass almost all the light to pass through with very little bending through with very little bending or scattering of the rays.or scattering of the rays.

You can see through it.You can see through it.

Examples:Examples: eyeglasses, empty eyeglasses, empty clear glass, clear window.clear glass, clear window.

Opaque,Opaque,Translucent and Translucent and

TransparentTransparent

Free Whiteboard Resources - Light and Dark -Transparent material.url

TranslucentTranslucent

Translucent Translucent Material: Allows only Material: Allows only some light to pass through, yet some light to pass through, yet scatter and bend the rays.scatter and bend the rays.

You can see through it, but not You can see through it, but not clearly.clearly.

Examples: frosted glass, clouds, Examples: frosted glass, clouds, thin paperthin paper

•

Opaque Transparent Translucent

3 Examples3 Examples

ReflectionReflection ReflectionReflection: When light hits a : When light hits a

particular surface and bounces particular surface and bounces back. back.

Reflection of LightReflection of Light

When light reaches a solid object one of the When light reaches a solid object one of the things that can happen is that the light can be things that can happen is that the light can be reflected. The reflected light can be either reflected. The reflected light can be either partially or completely reflected based on the partially or completely reflected based on the elasticity of the material. For this reason, metals elasticity of the material. For this reason, metals make good reflective surfaces. make good reflective surfaces.

Law of ReflectionLaw of Reflection

The law of reflection states that the angle The law of reflection states that the angle between the incident ray and the normal is between the incident ray and the normal is equal to the angle between the reflected equal to the angle between the reflected ray and the normal. ray and the normal.

This law applies to regular, partial and This law applies to regular, partial and diffusediffuse reflection. reflection.

Regular ReflectionRegular Reflection

Regular ReflectionRegular Reflection: : Regular reflection describes reflection off of Regular reflection describes reflection off of

very smooth surfaces. It is the type of very smooth surfaces. It is the type of reflection that can be seen with a mirror or off reflection that can be seen with a mirror or off of a lake on a day without any wind. of a lake on a day without any wind.

Diffuse ReflectionDiffuse Reflection: :

When light is incident off of a rough or irregular When light is incident off of a rough or irregular surface, it can be defined as irregular of surface, it can be defined as irregular of diffuse reflection. This occurs hen you look at diffuse reflection. This occurs hen you look at the same lake on a windy day. the same lake on a windy day.

RefractionRefraction

Refraction of LightRefraction of Light

Refraction of LightRefraction of Light: : Refraction is defined as the bending of light Refraction is defined as the bending of light

due to a change in its speed. This is why a due to a change in its speed. This is why a straw appears bent in a glass of water or straw appears bent in a glass of water or why a swimming pool appears shallower why a swimming pool appears shallower than it really is. The differences in the than it really is. The differences in the position and dimensions are considered position and dimensions are considered apparent because they have not actually apparent because they have not actually changed. The differences are caused by the changed. The differences are caused by the changing speed of the light as it transitions changing speed of the light as it transitions to different media. to different media.


Refraction: Refraction: The change in direction of a The change in direction of a wave as it crosses the boundary between wave as it crosses the boundary between two mediums in which the wave travels at two mediums in which the wave travels at different speeds.different speeds.

Light bending as it passes through Light bending as it passes through different material.different material.


Remember that light (like all waves) travels at Remember that light (like all waves) travels at constant speed within a medium constant speed within a medium

The speed changes as light changes medium The speed changes as light changes medium Light travels faster in less dense mediums Light travels faster in less dense mediums In less dense mediums the light moves away from In less dense mediums the light moves away from

the normal the normal Moves slower in more dense mediums Moves slower in more dense mediums In more dense mediums the light moves towards In more dense mediums the light moves towards

the normal the normal

RefractionRefraction / Reflection / ReflectionConvexConvex / / ConcaveConcave

A A refracting telescoperefracting telescope uses two uses two convex convex lenses lenses to magnify images in the sky. A to magnify images in the sky. A reflectingreflecting telescope uses a concave mirror, a plane telescope uses a concave mirror, a plane mirror, and a convex lens to do the same job. mirror, and a convex lens to do the same job.

A A microscope,microscope, like a like a reflectingreflecting telescope, uses telescope, uses a concave mirror, a plane mirror, and a a concave mirror, a plane mirror, and a convex lens. However, they are used to convex lens. However, they are used to magnify very small images on slides not in the magnify very small images on slides not in the sky. sky.

Convex LensesConvex LensesConvex Lenses: Are thinker in the Convex Lenses: Are thinker in the

middle then on the edges. Light is middle then on the edges. Light is refracted inward causing the rays to refracted inward causing the rays to converge- changing the focal point.converge- changing the focal point.

Convex and Concave Convex and Concave LensesLenses

Convex lensesConvex lenses, on the other hand, refract light rays in toward a central , on the other hand, refract light rays in toward a central point. The image seen through a convex lens is upside down when the lens point. The image seen through a convex lens is upside down when the lens is held away from your face, but the image is magnified and right side up is held away from your face, but the image is magnified and right side up when the lens is held closer to your eye.when the lens is held closer to your eye.

Concave LensesConcave Lenses Concave Lenses: Concave Lenses: Are thinker on the Are thinker on the

edges then in the middle. Light edges then in the middle. Light refracted outward causing the rays refracted outward causing the rays to diverge- changes the focal point.to diverge- changes the focal point.

Concave Concave / / ConvexConvex lenses lenses

A A concave lensconcave lens is thicker at the edges than it is at the is thicker at the edges than it is at the center.center.

A A convex lensconvex lens is thicker in the middle than it is at its is thicker in the middle than it is at its edges. edges.

A A concave lensconcave lens refracts light rays spreading them refracts light rays spreading them outward producing an image that is upright and smaller outward producing an image that is upright and smaller than the actual object. than the actual object.

A A convex lensconvex lens refracts light rays inward. If a convex lens refracts light rays inward. If a convex lens is held close to a person’s eyes, they will see an image is held close to a person’s eyes, they will see an image that is upright and larger than the actual object. If the that is upright and larger than the actual object. If the convex lens is held further away from a person’s eyes, convex lens is held further away from a person’s eyes, they will see an image upside down. they will see an image upside down.

PART 2PART 2

COLORS OF THE RAINBOWCOLORS OF THE RAINBOW

Magic School BusMagic School Bus

Watch this video!

Visible LightVisible Light Visible light:Visible light: is a combination of several is a combination of several

wavelengths of light traveling together wavelengths of light traveling together that the human eye can see.that the human eye can see.

Visible lightVisible light waves are the only waves are the only electromagnetic waves we can see. We electromagnetic waves we can see. We see these waves as the colors of the see these waves as the colors of the rainbow. Each color has a different rainbow. Each color has a different wavelength. Red has the longest wavelength. Red has the longest wavelength and violet has the shortest wavelength and violet has the shortest wavelength. wavelength.

ROYGBIVROYGBIV

Visible color spectrum is made up of Visible color spectrum is made up of seven colors (seven colors (RedRed,, Orange,Orange, YellowYellow, , Green,Green, Blue,Blue, Indigo Indigo, and , and Violet)Violet)

A rainbow spans a continuous spectrum of colors; the A rainbow spans a continuous spectrum of colors; the distinct bands are an artifact of human color vision. In distinct bands are an artifact of human color vision. In Roy G. BivRoy G. Biv,, the colors are arranged in the order of the colors are arranged in the order of decreasing wavelengths, with red being 650 nm and decreasing wavelengths, with red being 650 nm and violet being about 400 nm. violet being about 400 nm.

Visible SpectrumVisible Spectrum

The The visible spectrumvisible spectrum is the portion of the is the portion of the electromagnetic spectrum that is visible to electromagnetic spectrum that is visible to (can be detected by) the human eye .(can be detected by) the human eye .

It is made of seven colors.It is made of seven colors. RedRed,, Orange,Orange, YellowYellow, , Green,Green, Blue,Blue, Indigo Indigo, ,

and and Violet)Violet)

PrismPrism

Prism: a transparent solid body, often Prism: a transparent solid body, often having triangular bases, used for having triangular bases, used for dispersing light into a spectrum or for dispersing light into a spectrum or for reflecting rays of light.reflecting rays of light.

What is a prism Fun Science Age-Old Questions (Family & Education Nature & Planet).url

PrismPrism Different colors of light bend at Different colors of light bend at

different angles when passing different angles when passing through a prism.through a prism.

Prism ActivityPrism Activity

White light is part of the visible spectrum which happens to be made White light is part of the visible spectrum which happens to be made up of many different colors. up of many different colors.

When light travels it may collide with different molecules and when When light travels it may collide with different molecules and when this occurs the light will scatter. this occurs the light will scatter.

Therefore the colors many scatter in very different way.Therefore the colors many scatter in very different way. In this lab students will investigate the scattering effect light has and In this lab students will investigate the scattering effect light has and

how it may relate to the white light and how the sun emanate upon how it may relate to the white light and how the sun emanate upon Earth Earth

-NC State STEM Program -NC State STEM Program

MaterialsMaterials

A clear plastic container; 8 x 8 inches long & 4 inch in width (a small A clear plastic container; 8 x 8 inches long & 4 inch in width (a small clear plastic fish tank works great)clear plastic fish tank works great)

PrismsPrisms WaterWater FlashlightsFlashlights Powdered milkPowdered milk Measuring cupsMeasuring cups TablespoonsTablespoons Index cards Index cards A separate sheet of paper to record data and resultA separate sheet of paper to record data and result Color Coded Wavelengths ChartsColor Coded Wavelengths Charts

Color Coded Wavelength ChartColor Coded Wavelength Chart

WavelengthWavelength Color of LightColor of Light 5.7–5.9 x 10-7m Yellow5.7–5.9 x 10-7m Yellow 3.9–4.5 x 10-7m Violet3.9–4.5 x 10-7m Violet 6.2–7.7 x 10-7m Red6.2–7.7 x 10-7m Red 4.9–5.7 x 10-7m Green4.9–5.7 x 10-7m Green 5.9–6.2 x 10-7m Orange5.9–6.2 x 10-7m Orange 4.5 – 4.9 x 10-7m Blue4.5 – 4.9 x 10-7m Blue

Step 1Step 1

Use the flash light and shine a light beam Use the flash light and shine a light beam through the prism. through the prism.

Record the color spectrum you see on the Record the color spectrum you see on the blank paper, continuing to turn and record blank paper, continuing to turn and record each color you see and match the color to each color you see and match the color to the Color Coded Wavelength Chart (white the Color Coded Wavelength Chart (white light spectrum) light spectrum)

Step 2Step 2

Fill the clear tank with water.Fill the clear tank with water. Use the flashlight and shine a light beam Use the flashlight and shine a light beam

through the side and end of the tank of through the side and end of the tank of water. water.

Then record what color you see. Then record what color you see. Match the color to the Color Coded Match the color to the Color Coded

Wavelength Chart. Coninue to match each Wavelength Chart. Coninue to match each color and wavelength throughout the labcolor and wavelength throughout the lab

Step 3Step 3

Tape an index card at one end of the clear tankTape an index card at one end of the clear tank The teacher will turn off the classroom lightsThe teacher will turn off the classroom lights Flash a beam of light through the tank at the Flash a beam of light through the tank at the

index card at the end of the tank and record index card at the end of the tank and record what color you see and match the color and what color you see and match the color and wavelength to the chart. wavelength to the chart.

Then shine the light beam through the side and Then shine the light beam through the side and record the color result and wavelengthrecord the color result and wavelength

Step 4Step 4

The teacher will turn the classroom lights onThe teacher will turn the classroom lights on Add ¼ cup of powdered milk to the tank of water and stir Add ¼ cup of powdered milk to the tank of water and stir

the tank of water with the spoon for approximately 2 the tank of water with the spoon for approximately 2 minutes. The powered milk should be full dissolved minutes. The powered milk should be full dissolved

Take the index card off the side of the tankTake the index card off the side of the tank Shine flash light beam through the water tank from the Shine flash light beam through the water tank from the

end and side and record what color you see, again end and side and record what color you see, again match the color to the colors wavelength.match the color to the colors wavelength.

Step 5Step 5

Tape the index card to one end of the tankTape the index card to one end of the tank The teacher will turn off the classroom lightsThe teacher will turn off the classroom lights Shine the flashlight beam through the tank to the end of Shine the flashlight beam through the tank to the end of

the tank at the index card and record what you see. the tank at the index card and record what you see. Then shine the light beam through the side and record Then shine the light beam through the side and record the resultsthe results

Add 2 tablespoon of powdered milk and repeat the Add 2 tablespoon of powdered milk and repeat the process and record the resultsprocess and record the results

Compare the results from the color and wavelengths Compare the results from the color and wavelengths from the end and side of the tank. from the end and side of the tank.

Data AnalysisData Analysis

With your team, analyze the data With your team, analyze the data recorded.recorded.

How do waves compare and contrast? How do waves compare and contrast?

Documents

Light and Optics Light and Optics 6.P.1.2 Students will explain the relationship between visible light, the electromagnetic spectrum, and sight