Light.ppt

Light

Sir Isaac Newton

Sir Isaac Newton

What is Light?

Light is a form of energy that is made up of many colors.

When white light passes through a prism, it separates into the colors of the rainbow.

4-5.2 _______________ _______________ _______________ _______________ _______________ _______________ _______________

White light separates into the colors of

the rainbow called a

spectrum.

ROY G. BIV

(Visible Spectrum)

B- Blue

I- Indigo

V- Violet

The colors separate because

each one has a different amount

of energy (movement).

Pass Question

Which of the following best describes what Newton discovered about prims?

A.They absorb white light. B.They display infrared light.

C.They convert light energy into waves.

D.They split light into the visible spectrum.

Pass Question

A.Red B.Green C.Yellow D.Blue

Pass Question

Which is the best definition of the visible spectrum?

A.The colors people see that make up white light B.The colors of the rainbow

C.The colors that come out a prism D.The colors red, blue, and yellow

Reflection

of Light

Reflection

of Light

4-5.3

When light is reflected, it bounces back from a surface.

When light strikes an object, some of the light reflects off of it and can be seen by your eyes.

When light strikes a smooth, shiny object (for example

mirror or still water), it is reflected so that you see a reflection very similar to the object being reflected.

Reflection allows objects to be seen that do not produce their own light.

Reflection

of Light

Absorption

of Light

Absorption

of Light

4-5.3

When light is absorbed, it remains in the material. It DOES NOT pass through or reflect back.

Why does a red apple look red?

(

Reflected

light and

Absorbed

light)

4-5.3

The color of light that is reflected off an object is the color that the object is. An object that reflects only red light will appear red.

All other colors of light striking the apple are absorbed

Why does a red apple look red?

(

Reflected

light and

Absorbed

light)

4-5.3

When you look at a yellow

banana, yellow is reflected back to your eye.

All other colors are absorbed into the banana except for

Why does a

green

tree look

green

?

(

Reflected

light and

Absorbed

light)

Pass Question

Which best explains why people see grass as green?

A.The pigment in the grass reflects only green light. B.The grass absorbs green light from the sun.

C.Green light changes when it hits the grass.

D.The grass is opaque and does not allow green light through.

Pass Question

Which best explains why objects can be seen? A.Objects reflect light.

B.Light shines on objects.

C.Objects are made of matter. D.Light refracts off objects.

Pass Question

A.In a wavy line B.In a broken line C.In a straight line D.In a curved line

Refraction

of Light

Refraction

of Light

4-5.3

When light is refracted, it passes from one transparent material to another, and slows down or bends.

Light rays slow down when they go through water or glass.

Refraction makes a pencil in water look bent or

broken. We see things differently when light passes from air to water.

During refraction, when light rays bend it makes the pencil in water look bent or broken.

Refraction

of Light

Pass Question

Which if the following is a true statement about light?

A.It is made of only one color. B.It is made of many colors.

C.It cannot travel through a vacuum. D.It cannot travel through solids.

Pass Question

Which of the following explain how reflection and refraction of light are similar?

A.Both involve light bouncing

B.Both involve light being absorbed C.Both involve only white light

D.Both involve bending light

Pass Question

Which of the following explain why people can see objects?

A.The pupil of the eyes gets less light.

B.The light reflected off objects enters the eye. C.The lens of the eye gets larger.

D.The objects absorb light.

Transparent

Material

All light can pass through this material.

When you look through it, objects are clear. Examples are air, water, and glass.

Translucent

Material

Some light can pass through this material.

When you look through it, objects are blurry. Examples are wax paper, and thin notebook

paper.

Opaque

Material

This type of material blocks all light.

When you look through it, you can’t see anything. Examples are thick paper and cardboard.

All light can pass through this type of material.

When you look through this material, objects appear clear. Ex: Air, water, and glass

Some light can pass through this material.

When you look through this material, objects appear blurry. Ex: Wax paper, clouds, and thin notebook paper

This type of material blocks all light.

When you look through this material, you can’t see anything. Ex: Wood, thick paper, and cardboard

Translucent

What happens when LIGHT

hits an object?

Three (3) things can happen:

1.Light passes completely. (if the object is…) 2.Light is blurred. (if the object is…)

3.Light is blocked. (if the object is…)

What happens when LIGHT

hits an object?

Materials:

• _{Transparent object} • _{Translucent object} • _{Opaque object}

• _Flashlight • _{Plastic plate}

What happens when LIGHT

hits an object?

Procedure:

1.Observe the 3 different objects.

2.Predict what will happen when you shine a light on each object.

3.Shine a light on each object and observe what happens.

4.Sketch a picture of what happens and record your data in your science notebooks.

What happens when LIGHT

hits an object?

What happens when LIGHT

hits an object?

What happens when LIGHT

hits an object?

Pass Question

Glass, water, and clear plastic allow light to pass through them. Which word best describes these objects?

A.Translucent B.Refractive C.Transparent D.opaque

Pass Question

Will collected data about how light responds to transparent (lets 100% of the light through), translucent (lets 40% of

light through), and opaque (lets 0% of light through) objects. Which of the following should Will use to best represent his data?

A.Flow chart B.Line graph C.Bar graph D.table

Pass Question

Will collected data about how light responds to transparent (lets 100% of the light through), translucent (lets 40% of

light through), and opaque (lets 0% of light through) objects. Which is the best inference about Will’s data? A.All of the light passes through transparent objects. B.No light passes through opaque objects.

C.No light will pass through a solid piece of metal.

D.Some light that hits translucent objects is refracted.

Pass Question

Which best describes what happens when light reaches translucent materials?

A.All of light passes through.

B.Some light passes through and some bounces off in different directions.

C.The light is reflected at a 90 degree angle.

D.Some light bounces off in different directions, while some light is absorbed.

Pass Question

Mrs. Dickson wants to install windows in her office that will protect her privacy. What is the best material to have the windows made from? A.Clear plastic

B.Clear glass C.Frosted glass D.Thin paper