Light!

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Apple in the Dark

Imagine you are sitting at a table with a red apple in front of you. Your friend closes the door and turns off all the lights. It is totally dark in the room. There are no windows in the room or cracks around the door. No light can enter the room.

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Which statement do you believe best describes how you would see the apple in the dark:

• You will not see the red apple, regardless of how long you are in the room.
• You will see the red apple after your eyes have had time to adjust to the darkness.
• You will see the apple after your eyes have had time to adjust to the darkness, but you will not see the red color.
• You will see only the shadow of the apple after your eyes have had time to adjust to the darkness.
• You will see only a faint outline of the apple after your eyes have had time to adjust to the darkness.

Essential Questions for today:

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• What kind of path does light take?

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• How can we see?

What produces light? What do we use light for?

·Sun

·Flashlight

·Firefly

·Phones

·Light bulb

·Lightning

·Fire

·Others?

·See

·Communicate

·Plants grow

·Heat

·Solar Energy

·Cutting (lasers)

·Tanning

·Others?

Light -a form of energy that allows us to see.

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Emit- to make or send out from a source

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Reflect- to move in one direction, hit a surface, and then move in another direction.

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How does light travel?

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·In a straight line or does it bend and curve?

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·What does the demo tell us about how light travels?

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Video

• This is what light would have to do if the cards were not lined up.
• Because light could not go through the holes when they were not lined up we know that...

Light travels in a straight line!

How do you know?

Apple in the Dark

Imagine you are sitting at a table with a red apple in front of you. Your friend closes the door and turns off all the lights. It is totally dark in the room. There are no windows in the room or cracks around the door. No light can enter the room.

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Which statement do you believe best describes how you would see the apple in the dark:

• You will not see the red apple, regardless of how long you are in the room.
• You will see the red apple after your eyes have had time to adjust to the darkness.
• You will see the apple after your eyes have had time to adjust to the darkness, but you will not see the red color.
• You will see only the shadow of the apple after your eyes have had time to adjust to the darkness.
• You will see only a faint outline of the apple after your eyes have had time to adjust to the darkness.

No Light, No Sight!

Draw the light rays so that the cat can be seen.

Light is emitted from a light source, reflects off an object, then enters our eyes.

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Light must enter our eyes for us to see.

Draw the light rays so that the cat can be seen.

Did we answer these questions?

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·What kind of path does light take?

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·How can we see?

Final question:

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If you can see an object, what do you KNOW is happening?

Apple in the Dark

Imagine you are sitting at a table with a red apple in front of you. Your friend closes the door and turns off all the lights. It is totally dark in the room. There are no windows in the room or cracks around the door. No light can enter the room.

​

Which statement do you believe best describes how you would see the apple in the dark:

• You will not see the red apple, regardless of how long you are in the room.
• You will see the red apple after your eyes have had time to adjust to the darkness.
• You will see the apple after your eyes have had time to adjust to the darkness, but you will not see the red color.
• You will see only the shadow of the apple after your eyes have had time to adjust to the darkness.
• You will see only a faint outline of the apple after your eyes have had time to adjust to the darkness.

No Light, No Sight!

Draw a diagram showing how you can see an object.

(use a ruler and label each item)

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Creating models

Create a model showing how someone can see an object.

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Create a model showing how someone can see the object behind them. (They don’t really need to see it, just demonstrate with the model.)

Materials:

• flashlight (off)
• object
• string

Draw a diagram showing how you can use a mirror to see behind you.

(use a ruler and label each item)

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Our light source (big circle with arm)

Travels in a straight line (tomahawk chop)

To the object (create an outline of box with fingers)

and reflects the light (clap)

traveling in a straight line (tomahawk chop)

to the mirror (hands make mirror off to side)

which reflects the light (clap)

in a straight line (tomahawk chop)

to our eye (point to eye)

http://www.amblesideprimary.com/ambleweb/mentalmaths/protractor.html

Using a protractor

http://www.ixl.com/math/grade-5/measure-angles-with-a-protractor

Warm Up:

Find and play “Alien Angles” in Schoology

Angles Song

Student A

Student B

Lab Conclusion:

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• What pattern do you notice?

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• What rule could you make about how light reflects?

What's happening to the angles?

Angle in ? angle out

The law of reflection:

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The angle of incidence is equal to the angle of reflection

angle of incidence

angle of reflection

or

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Angle in = Angle out

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video

COLORS

White light = All colors of light combined.

Color spectrum-The ordered separation of colored light that combine to create white light.

White light consists of 7 colors in a specific order:

red, orange, yellow, green, blue, indigo, and violet.

Prism Demo

How are objects colored with white light?

The answer is Absorption!

Absorb - To take in or soak up

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·An object that appears red absorbs all colors but reflects red.

A lemon absorbs all colors but reflects yellow light to our eyes.

A red apple absorbs all colors except red light that is reflected to our eyes.

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Predictions

What will happen?

Why?

Black and White paper under a lamp.

Black absorbs all colors and reflects none.

White absorbs no colors and reflects all colors.

Results

·What happened?

·Why?

Light is a form of energy.

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The more light energy something absorbs, the warmer it gets.

What colors are absorbed?

What colors are reflected?

Vantablack

A super-black coating, darkest man-made substance. Absorbs virtually all light and reflects so little...described as the closest thing to a black hole we'll ever see.

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Reduces stray light, improving the ability of sensitive telescopes to see the faintest stars.

Quick Write

Explain why the top of this bus is painted white.

(Use what you've learned about reflection and absorption of light.)

Study Jams

Do only mirrors reflect?

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Does all light get reflected?

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(Reflection Lab)

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If all objects reflect light, why do some reflect a perfect image and others do not?

Paper under a microscope

Regular reflection- When objects are smooth, they keep the reflected light rays parallel and produce an image.

Diffuse reflection- When objects are not smooth they scatter the light, sending it in all directions. Does not reflect an image.

Foil, Wax paper, Clear film

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• How are they different?

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• How are the three materials similar?

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Transparent Translucent Opaque

All light can go through

Some/little light can go through

No light can go through

Transparent- an object that allows all light to pass through.

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Can see clearly through to the other side. (window)

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“Parents can see right

through me.”

Translucent- an object that only allows some of the light to pass through.

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Can block a little of the light, or a lot of the light. (sunglasses)

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TranSLucent

“Some Light”

Opaque- an object that light cannot pass through (brick wall)

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“Opaque Steak”

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“Nopaque”

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Transparent Translucent Opaque

Which objects create shadows?

Which objects create the BEST shadows?

Most

Transparent

Translucent

Most

Opaque

Stained Glass Samples

Transmit- to allow light to pass through

Add each sample to your notebook and label as:

• transparent
• translucent
• opaque

How are translucent and transparent similar?

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How are translucent and opaque similar?

Perfectly

Transparent

Translucent

Perfectly

Opaque

Opacity Spectrum

Using the spectrum, when do shadows start to form?

What is a shadow?

A shadow appears when light cannot pass (transmit) through an object.

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Which objects create shadows?

Translucent and opaque objects create shadows.

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Which objects create the darkest shadows?

Opaque objects create the darkest shadows.

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Shadows!

Study Jams - Shadows

1. light source -> object -> shadow

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(Always in a straight line)

2. Shadows will resemble the shape of the object creating them.

Where is the sun?

Directions:

• Draw and cut out your design on black paper - the bigger the better!
• Cut out any inside lines you might want to break up the sections.
• Pick out a pinch of tissue paper.
• This will probably not cover your whole design. That’s ok!
• Place your design on the ½ sheet of contact paper. Fill in the sections with the colorful tissue paper.
• When you are finished, peel off the other ½ contact paper and fold it over to sandwich in your design.
• Cut out the design if you don’t use a rectangle (cut off the excess).

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Directions:

• Draw and cut out your design on black paper - the bigger the better!
• Trace the outside edge of your design on wax paper (use Sharpie).
• Cut out the inside of the paper design.
• Pick out 10-12 pieces of tissue paper.
• Cover the wax paper design with tissue paper (use GLUE STICK).

This will probably not cover your whole design. That’s ok!

• Glue your black outline over the tissue paper (USE LIQUID GLUE)
• Cut out the design (cut off the excess tissue paper and wax paper).

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Brian is stranded in the wilderness and is attempting to spearfish…

DEMO

Medium- a substance light CAN pass through

Refraction - The bending of light as it moves from one medium to another.

Refraction Lab

1. Cup and straw (eye level)

2. Magic Penny (read directions)

3. Secret Message (eye level)

Tips:

• hold paper away from beaker
• close one eye

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Wrap up:

Where and when does light refract?

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At the boundary between different mediums.

SWANSON

Lesson:

• Get art project, cut it out, and hang it up with our class!
• Color By Code
• Refraction Lab Sheet (back page) Secret Code bins passed around
• Refraction Lab- Pencil and Magic Penny with Swanson
• Read Hatchet

FERRARA Real World Workshop

NOW:

• Finish refraction lab
• Finish comic or writing
• Missing work
• Light color-by-code
• Refraction Lab- Pencil and Magic Penny (with Ferrara)
• Refraction Lab- Secret Code bin (passed around)

LATER:

• Opacity simulation on Chromebook

(today’s folder)

• Laser Maze
• Read

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• What was Brian trying to do?

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• What happened?

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• How was the problem solved?

Refraction - The bending of light as it moves from one medium to another

Does light need a medium to travel?

Think about how we see stars at night…

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No! Mediums can change light’s direction and speed, but they are not required.

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Liter of Light

What do you notice about the magnifying lenses?

Notebooks

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Magnifying lens observations

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(shape, size, what happens when...)

Lenses refracting

Concave Lens

Convex Lens

Thicker at the edges than it is at the middle

Thicker at the middle than it is at the edges

Concave Lens

Convex Lens

Makes objects appear smaller

Makes objects appear larger

Concave Lens

Convex Lens

• Some eyeglasses (rare)
• Flashlights

• Most eyeglasses
• magnifying lens
• microscope

Uses for lenses?

Water drop magnifier

·Read the newspaper

·Adjust the distance

·Try different drop sizes

What type of lens is in our eyes?

How eyeglasses work

Fresnel Lenses (fray-NEL)

Bell Ringer

This is a sun shade for a car's windshield. One side is silver and the other side is black.

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Explain why each side would be useful and when you would choose the silver or black side.

"The black side of the windshield would be useful in the winter because if you have it facing out to the sun and it will absorb the heat and let into the car because black absorbs all colors. In the summer the silver side would be useful because white reflects all colors and that will keep the car cool."

Science in action with Liter of Light

Prism- A transparent object that separates white light into colors of the spectrum.

Prism

White light breaks apart because the prism slows the colors down differently.

BrainPop- Rainbows

Mythbusters

• Light is NOT needed to see.
• White is the absence of color.
• Color is due to emission.
• Color is not related to light.
• Light can bend within a medium.
• Light needs a medium to travel.