Chapter Menu Lesson 1:What is light?What is light? Lesson 2:Light and MatterLight and Matter Lesson 3:Using LensesUsing Lenses Lesson 4:The Eye and.

Chapter Menu

Lesson 1: What is light?

Lesson 2: Light and Matter

Lesson 3: Using Lenses

Lesson 4: The Eye and Vision

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wavelength

frequency

medium

electromagnetic spectrum

11.1 What is light?

Light Transfers Energy

• Similar to water waves, light waves also carry energy from place to place.

11.1 What is light?

Parts of a Wave

• The distance between any two crests of any two troughs is the wavelength.

11.1 What is light?

Frequency and Wavelength

• The frequency of a wave is the number of wavelengths that pass a given point in one second.

11.1 What is light?

• As the frequency of a wave increases, wavelength decreases.

Electromagnetic Waves

• The substance through which a wave moves is called the medium.

11.1 What is light?

• Light is an electromagnetic wave, which is a type of wave that can travel in empty space as well as in matter.

A Range of Wavelengths

• The electromagnetic spectrum includes all electromagnetic waves.

11.1 What is light?

• It is arranged in order, from those with the longest wavelengths to those with the shortest wavelengths.

• Frequency increases as wavelength decreases, and is arranged in order of increasing frequency.

Visible Light

• The visible light spectrum is the range of electromagnetic waves human eyes can detect.

11.1 What is light?

• Visible light wavelengths are measured in nanometers (nm).

• The wavelengths range from 700 nm to 400 nm.

11.1 What is light?

Lesson 1 Review

What is the amplitude of a wave?

A distance from crest to crest

B distance from crest to trough

C distance from crest to resting position

D wavelength x frequency

11.1 What is light?

Lesson 1 Review

What is a wavelength?

A the distance from crest to trough

B the distance from crest to the rest position

C the distance from crest to crest

D the opposite of frequency

11.1 What is light?

Lesson 1 Review

What is the term for the substance through which a wave moves?

A medium

B substrate

C water

D vacuum

11.1 What is light?

End of Lesson 1

absorption

transmission

scattering

refraction

law of reflection

11.2 Light and Matter

The Interaction of Light and Matter

• All electromagnetic waves, including light, transfer energy from one place to another.

• When light rays hit matter, they can be absorbed, reflected, or pass through the matter.

11.2 Light and Matter

Absorption of Light

• The transfer of energy can cause the temperature of the material to increase.

• Absorption occurs when light rays hit a material, and some of the rays’ energy is transferred to the atoms in the material.

11.2 Light and Matter

Transmission of Light

• Whether the light waves are transmitted or absorbed depends on the wavelength of the light waves.

• Transmission occurs when light waves strike a material and pass through it, such as with glass.

11.2 Light and Matter

Scattering of Light• Scattering occurs when a material

causes light waves traveling in one direction to travel in all directions.

11.2 Light and Matter

Opaque, Transparent, and Translucent Materials

11.2 Light and Matter

• The three candleholders are made of different materials that absorb, transmit, and scatter light in different ways.

The Speed of Light in Different Materials

11.2 Light and Matter

• No object or wave can move faster than the speed of light in empty space.

• When light waves travel in matter, they move more slowly.

Refraction• Refraction occurs when a light ray changes direction

when it moves from one material to another.

11.2 Light and Matter

Refraction and Speed Changes• Light waves change direction—refract—when they

change speed moving from one medium to another.

11.2 Light and Matter

Refraction and Speed Changes (cont.)

The Visible Spectrum• White light is a combination of all light waves in the

visible light spectrum.

11.2 Light and Matter

• Almost any color of light can be made by mixing the three primary colors—red, green, and blue—in different amounts.

The Visible Spectrum (cont.) 11.2 Light and Matter11.2 Light and Matter

Reflection• According to the law of reflection, when a light ray is reflected from

a surface, the angle of incidence equals the angle of reflection.

11.2 Light and Matter

Regular and Diffuse Reflection• Light ray reflected from an uneven surface hits a spot in the surface that is at

a slightly different angle, causing the rays to go in many different directions.

• Diffuse reflection is the reflection of light rays from a rough surface.

11.2 Light and Matter

Regular and Diffuse Reflection (cont.)

• The smooth surface of a mirror reflects parallel light rays so that they remain parallel.

• This is called regular reflection.

11.2 Light and Matter

Reflection and Color• As white light strikes and object, some of the

light is absorbed and some is reflected.

• The reflected light enters your eyes and causes you to see the object.

11.2 Light and Matter

Color

Lesson 2 Review

What is the term for the process of transferring light energy to the molecules in a material?

A transmission

B absorption

C scattering

D refraction

11.2 Light and Matter

Lesson 2 Review

Which of the following does light travel fastest through?

A transparent objects

B empty space

C air

D water

11.2 Light and Matter

Lesson 2 Review

Why does an object appear to be blue?

A it absorbs the blue wavelength

B it scatters the blue wavelength

C it reflects all the other colors except blue

D it absorbs all the wavelengths except blue

11.2 Light and Matter

End of Lesson 2

11.3 Using Lenses

lens

convex lens

focal point

focal length

What is a convex lens?• A lens is a transparent object with at least one curved

side that causes light waves to bend.

• A convex lens is a lens that bulges outward.

11.3 Using Lenses

– Convex lens: parallel light rays are bent so they come together, or converge

– Concave lens: parallel light rays spread apart, or diverge

What is a convex lens? (cont.)

• A concave lens is thinner in the middle than at the edges.

11.3 Using Lenses

Light’s Path Through a Convex Lens• A light ray bends when it slows down moving from air

into the lens.

• The light ray bends again when it speeds up moving from the lens back into the air.

11.3 Using Lenses

Focal Point and Focal Length• The focal point is the point where all of the beams of

light converge.

• In a convex lens, all light rays traveling parallel to the optical axis are bent so that they pass through the focal point.

11.3 Using Lenses

Focal Point and Focal Length (cont.)

• The focal length is the distance from the center of the lens to the focal points.

11.3 Using Lenses

Image Formation by a Convex Lens• The image formed by a convex lens depends on the

position of an object relative to the focal point.

11.3 Using Lenses

Optical Instruments• An optical instrument uses lenses to focus light and

create useful images.

11.3 Using Lenses

• Different optical instruments do this by combining lenses in various ways.

• Types of optical instruments

– Cameras

– Telescopes

– Microscopes

Cameras• A camera is focused by moving various lenses back

and forth until a sharp image is formed.

11.3 Using Lenses

• The image is smaller than the object and is upside down.

• To take a picture, the shutter opens so that light enters the camera, and film or an electronic sensor is exposed.

Cameras (cont.)

• To control the amount of light that reaches the film or light sensor, cameras have a diaphragm or an aperture.

11.3 Using Lenses

Telescopes• As an object gets farther away, less of the light from the

object enters the openings in your eyes.

11.3 Using Lenses

• A telescope is an optical instrument that makes far-away objects seem closer.

• There are two basic types of telescopes—refracting and reflecting.

Refracting Telescopes• The objective lens in a refracting telescope is much

larger than the opening in a human eye.

11.3 Using Lenses

• Much more light from a distant object enters the objective lens than would enter an eye.

Reflecting Telescopes• An image of a distant object is formed inside the telescope tube

when light rays are reflected from the curved surface of a mirror.

11.3 Using Lenses

• The largest telescopes are reflecting telescopes.

Microscopes• The eyepiece lens of a microscope is positioned

so it is closer to the image than one focal length.

11.3 Using Lenses

• This makes the image enlarged by the objective lens even larger.

Lesson 3 Review

Where do all the beams of light passing through a convex lens converge?

A focal point

B optical axis

C two focal lengths from the lens

D in the center of the lens

11.3 Using Lenses

Lesson 3 Review

What happens to light when it moves from air into a convex lens?

A it is reflected

B it is scattered

C it slows down

D it speeds up

11.3 Using Lenses

Lesson 3 Review

Which uses a curved mirror to form an image that is magnified by an eyepiece lens?

A refracting telescope

B reflecting telescope

C camera

D microscope

11.3 Using Lenses

End of Lesson 3

11.4 The Eye and Vision

cornea

pupil

iris

retina

pigment

How the Eye Forms an Image• As light enters your eye, lenses in your eye

focus light to produce an image on the back of your eye.

• Special cells at the back of the eye convert the image into electrical signals that travel to your brain.

11.4 The Eye and Vision

Cornea• Light enters your eye through the cornea, which is a

clear area of the sclera—the outer layer of the eye.

11.4 The Eye and Vision

The Eye

Cornea

11.4 The Eye and Vision

Iris• The pupil is the dark opening into the interior of your

eye.

11.4 The Eye and Vision

• The pupil is surrounded by the iris—the colored part of your eye behind the cornea.

Lens

• The lens of your eye is convex and flexible.

11.4 The Eye and Vision

• The ciliary muscles attached to the lens change its shape depending on the distance of the object being looked at.

Retina• The retina is a sheet of light-sensitive cells in the

back of the eye.

11.4 The Eye and Vision

• Rod cells respond to dim light and cone cells enable you to see colors.

11.4 The Eye and Vision

11.4 The Eye and Vision

11.4 The Eye and Vision

Seeing Color• The response of cone cells to different wavelengths of

light cause you to see objects as having color.

11.4 The Eye and Vision

• Three types of cone cells:– One responds to the wavelengths of red and yellow light, causing you to see red.

– One responds to yellow and green light, causing you to see green.

– One responds to blue and violet light, causing you to see blue.

Pigment Colors• A pigment is a material used to change the color of

other materials or objects.

• The color of a pigment depends on the wavelengths of the light it reflects.

11.4 The Eye and Vision

Pigment Colors (cont.)

11.4 The Eye and Vision

Color Printing• The pictures in magazines are formed by many tiny

dots of color.

• Usually, the primary colors of pigments, as well as black, are used.

11.4 The Eye and Vision

Common Vision Problems• Color deficiency: either lack red or green cones, or

the cones do not function correctly

11.4 The Eye and Vision

Common Vision Problems (cont.)

• Nearsightedness: cannot see faraway objects clearly

11.4 The Eye and Vision

Common Vision Problems (cont.)

• Farsightedness: cannot see nearby objects clearly

11.4 The Eye and Vision

How are lenses used to correct vision?

Lesson 4 Review

What controls the amount of light that enters your eye?

A ciliary muscles

B cornea

C sclera

D iris

11.4 The Eye and Vision

Lesson 4 Review

What part of the eye enables you to see colors?

A pupil

B rod cells

C cone cells

D optic nerve

11.4 The Eye and Vision

Lesson 4 Review

Which describes a nearsighted eye?

A it is missing some cone cells or the cones don’t function properly

B the eyeball is too short for the lens to form a clear image

C the rods at the back of the eye do not function properly

D the eyeball is too long for the lens to form a clear image

11.4 The Eye and Vision

End of Lesson 4

Chapter Assessment

California Standards Practice

Concepts in Motion

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What is the wavelength range of visible light?

A 700–400 nm

B 200–600 nm

C 300–900 nm

D 800–300 nm

Chapter Assessment 1

What occurs when light waves strike a material and pass through it?

A reflection

B absorption

C transmission

D scattering

Chapter Assessment 2

Which is true according to the law of reflection?

A if light is not refracted, it is reflected

B parallel rays of light remain parallel when they are reflected

C the angle of incidence equals the angle of reflection

D the angle of reflection is twice the angle of incidence

Chapter Assessment 3

Which describes the image formed by an object more than two focal lengths from a convex lens?

A upside down and larger than the object

B upside down and smaller than the object

C right side up and smaller than the object

D right side up and larger than the object

Chapter Assessment 4

Which part of the eye contains light-sensitive rods and cones?

A sclera

B cornea

C optic nerve

D retina

Chapter Assessment 5

What property of a wave increases as wavelength decreases?

A crest

B trough

C frequency

D amplitude

CA Standards Practice 1

SCI 6.a

In which order does light pass through the parts of the eye?

A lens, retina, pupil

B lens, pupil, retina

C retina, lens, pupil

D pupil, lens, retina

CA Standards Practice 2

SCI 6.b

Which light waves are refracted the least after passing through a prism?

A red

B violet

C yellow

D blue

CA Standards Practice 3

SCI 6.c

What occurs when you look at an object at the bottom of a pool of water?

A reflection

B refraction

C absorption

D scattering

CA Standards Practice 4

SCI 6.f

What type of lens is present in both your eye and a microscope?

A objective

B eyepiece

C convex

D concave

CA Standards Practice 5

SCI 6.d

Concepts in Motion 1

Concepts in Motion 2

Concepts in Motion 3

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