Using Light
Teacher’s Guide
High/Middle
School
Editors:
Brian A. Jerome, Ph.D.
Stephanie Zak Jerome
Assistant Editor:
Anneliese Brown
Visual Learning Company
Brandon, Vermont
1-800-453-8481
www.visuallearningco.com
Using Light
Reviewers:
Reviewers:
Linda Arnone
Clark County Public School
Las Vegas, Nevada
Steve Welch
Rutland Middle School
Rutland, Vermont
John Peterson
Professor Emeritus of Physics
Providence, Rhode Island
Use and Copyright:
The purchase of this video program entitles the user the right to reproduce or
duplicate, in whole or in part, this teacher’s guide and the blackline master
handouts for the purpose of teaching in conjunction with this video, Using
Light. The right is restricted only for use with this video program. Any
reproduction or duplication, in whole or in part, of this guide and the student
masters for any purpose other than for use with this video program is
prohibited.
The video and this teacher’s guide are the exclusive property of
the copyright holder. Copying, transmitting or reproducing in
any form, or by any means, without prior written permission
from the copyright holder is prohibited (Title 17, U.S. Code
Sections 501 and 506).
081900
Visual Learning Company 1-800-453-8481
2
Using Light
Viewing
Clearances
The video and accompanying teacher’s guide are for
instructional use only. In showing these programs, no
admission charges are to be incurred. The programs are to be
utilized in face-to-face classroom instructional settings,
library settings, or similar instructional settings.
Duplication rights are available, but must be negotiated with
the Visual Learning Company.
Television, cable, or satellite rights are also available, but
must be negotiated with the Visual Learning Company.
Closed circuit rights are available, and are defined as the use
of the program beyond a single classroom but within a single
campus. Institutions that wish to utilize the program in
multiple campuses must purchase the multiple campus version
of the program, available at a slightly higher fee.
Discounts may be granted to institutions interested in
purchasing programs in large quantities. These discounts may
be negotiated with the Visual Learning Company.
Visual Learning Company 1-800-453-8481
3
Using Light
Table of
Contents
Page
National Standards Correlations
6
Student Learning Objectives
7
Assessment
8
Introducing the Video
9
Video Viewing Suggestions
9
Video Script
11
Answers to Student Assessments
16
Answers to Student Activities
17
Assessment and Student Activities Masters
18
Visual Learning Company 1-800-453-8481
4
Using Light
A Message from our
Company . . .
Dear Educator:
Thank you for your interest in the educational videos produced by the
Visual Learning Company. We are a Vermont-based, family owned and
operated business specializing in the production of quality educational
science videos and materials.
We have a long family tradition of education. Our grandmothers graduated
from normal school in the 1920’s to become teachers. Brian’s mother was
an elementary teacher and guidance counselor, and his father was a high
school teacher and superintendent. This family tradition inspired Brian to
become a science teacher and to earn a Ph.D. in education, and lead
Stephanie to work on science educational programs at NASA.
In developing this video, accompanying teacher’s guide, and student
activities, our goal is to provide educators with the highest quality materials,
thus enabling students to be successful. In this era of more demanding
standards and assessment requirements, supplementary materials need to be
curricular and standards based - this is what we do!
Our videos and accompanying materials focus on the key concepts and
vocabulary required by national and state standards and goals. It is our
mission to help students meet these goals and standards, while experiencing
the joy and thrill of science.
Sincerely,
Brian and Stephanie Jerome
Visual Learning Company 1-800-453-8481
5
Using Light
National Standards
Correlations
National Science Education Standards
(Content Standards: 5-8, National Academy of Sciences, c. 1996)
Science as Inquiry - Content Standard A:
As a result of activities in grades 5-8, all students should develop:
• Abilities necessary to do scientific inquiry
• Understandings about scientific inquiry
Physical Science - Content Standard B:
As a result of their activities in grades 5-8, all students should develop
an understanding of how:
• Light interacts with matter by transmission (including refraction).
To see an object, light from the object - emitted by or scattered
from it - must enter the eye.
Benchmarks for Science Literacy
(Project 2061 - AAAS, c. 1993)
The Physical Setting - Motion (4F)
By the end of the 8th grade, students should know that:
• Light from the sun is made up of a mixture of many different colors
of light, even though to the eye the light looks almost white. Other
things that give off or reflect light have a different mix of colors.
• Something can be “seen” when light waves emitted or reflected by
it enter the eye.
Visual Learning Company 1-800-453-8481
6
Using Light
Student Learning
Objectives
Upon viewing the video and completing the enclosed student
activities, students should be able to do the following:
•
Define and explain the processes of reflection, diffraction, and
refraction;
•
Differentiate between transparent, translucent, and opaque
objects;
•
Explain how the processes of reflection and absorption affect
the colors we see in objects;
•
Understand that white reflects all colors of the
spectrum, and that black absorbs all colors of the spectrum;
•
Explain how polarized lenses, including polarized
sunglasses, reduce glare;
•
Describe the Law of Reflection utilizing the terms angle of
incidence and angle of reflection;
•
Identify and describe the characteristics of plane mirrors,
concave mirrors, and convex mirrors; and
•
Describe the characteristics and some of the uses of concave
and convex lenses.
Visual Learning Company 1-800-453-8481
7
Using Light
Assessment
Preliminary Test:
The Preliminary Test, provided in the Student Masters section, is an
assessment tool designed to gain an understanding of student preexisting
knowledge. It can also be used as a benchmark upon which to assess
student progress based on the objectives stated on the previous pages.
Video Review:
The Video Review, provided in the Student Masters section, can be used as
an assessment tool or as a student activity. There are two main parts. The
first part contains questions titled “You Decide” that can be answered during
the video. The second series of ten questions consists of a video quiz to be
answered at the conclusion of the video.
Post-Test:
The Post-Test, provided in the Student Masters section, can be utilized as an
assessment tool following student completion of the video and student
activities. The results of the Post-Test can be compared against the results of
the Preliminary Test to assess student progress.
Visual Learning Company 1-800-453-8481
8
Using Light
Introducing the
Video
We use light nearly every waking moment. From the time we wake up in
the morning until the time we go to sleep, we use light to navigate, read, do
work and recreate. Before showing the video, ask students to create a list of
some of the ways they have used light today. Next, ask them to name some
different sources of light. This list may include such things as the sun, light
bulbs, fire, and television. You may also want to ask students about some
ways we manipulate light to improve our lives. Examples include mirrors,
eyeglasses and the lights on vehicles. Tell students to carefully watch the
video for examples of how light enables us to see color, and how light can
be manipulated by humans.
Video Viewing
Suggestions
You may want to photocopy and distribute the Student Master, “Video
Review.” You may choose to have your students complete this Master while
viewing the program or to do so upon its conclusion.
The program is approximately 20-minutes in length and includes a tenquestion video quiz. Answers are not provided to the Video Quiz on the
video, but are included in this teacher’s guide. You may decide to either
grade student quizzes as an assessment tool or to review the answers in
class.
The video is content-rich with numerous vocabulary words. For this reason
you may want to periodically stop the video to review and discuss new
terminology and concepts.
Visual Learning Company 1-800-453-8481
9
Using Light
Student Assessments
and Activities
Assessment Masters:
•
Preliminary Test
•
Video Review
•
Post-Test
Student Activity Masters:
•
Mirror Images
•
Reappearing Pennies
•
Flashlight Physics
•
Understanding Optics
•
Vocabulary of Using Light
Visual Learning Company 1-800-453-8481
10
Using Light
Video ScriptUsing Light
1. One of the first ways children learn to describe their world is through the use of colors.
2. We know that the sky behind these geese appears blue,...
3. ...and that this jacket appears red...
4. . . . and that this sunset appears orange.
5. But where do colors come from?
6. How do our eyes receive and process color?
7. And what role does light play in enabling us to see color?
8. During the next few minutes we’re going to explore these questions about color,...
9. . . . while also taking a look at some of the properties of light, and . . .
10. . . . the way it interacts with matter.
11. Graphic Transition – Light in Action
12. The rays of the sun bouncing off the surface of this lake are blinding.
13. As is the light from this mirror.
14. You Decide!
What’s the term used to describe the process of light bouncing off objects?
15. That’s right, reflection. This is the process of light bouncing off objects. This ice is
reflecting the bright rays of the sun.
16. Shiny surfaces, such as ice and water, can reflect a large amount of the light that
strikes them.
17. Light is not only reflected, but can also be transmitted or absorbed.
18. (Sound of hammer breaking glass)
19. Glass is a breakable material that allows light, but not objects, to pass through it.
20. A substance such as clear water allows most light to pass through, allowing us to see
this purple starfish. The water is said to be transparent.
21. You Decide!
What is the difference between this plastic wrap and this wax paper?
22. This plastic wrap is transparent, allowing most of the light to pass through it, which
enables us to clearly see the fruit in the bowl.
23. The wax paper is not transparent, but instead is translucent.
24. Translucent materials only allow some light to pass through them. Translucent
materials scatter light.
25. Many plastics are translucent,...
26. . . . as are these curtains, allowing some light to pass through. The objects behind
them cannot clearly be seen.
27. In the case of this duck, it is neither transparent nor translucent. It’s opaque.
28. It is not possible to see through opaque objects.
29. Opaque objects tend to absorb some light and reflect some light.
Visual Learning Company 1-800-453-8481
11
Using Light
Script
30. This helps explain how we see the color in objects. Let’s take a closer
look at color.
31. Graphic Transition - Color
32. The mountains seen here in early summer are a sea of green.
33. What causes this green color?
34. Millions of green leaves give these hills their green color. The sun produces light in a
variety of colors, including red, orange, yellow, green, blue, indigo and violet.
35. Green leaves absorb many of the colors coming from the sun.
36. Plants use these wavelengths of color along with other electromagnetic energy to
make food via the process of photosynthesis.
37. But leaves do not absorb green light.
38. Instead, green is reflected back and is the color we usually see the most when
looking at a plant.
39. The brilliant color of this bright red car behaves similarly.
40. The car absorbs all of the colors of the spectrum, except red, which it reflects.
41. On the other hand, this black car does not reflect any of the colors. Instead, black
absorbs all colors. Black is produced when the colors of the spectrum are absorbed.
42. You may have noticed that black objects, such as this road, tend to get warm during
sunny weather. That is partly due to the fact that black absorbs all of the colors of the
light spectrum.
43. The opposite holds true of white. White reflects all of the colors in the spectrum
44. And that is why it is a good idea to wear white in warm weather, to help keep the
body cooler.
45. Graphic Transition - Polarized Light
46. Goggles are helping this skier see the terrain as she speeds down the slope.
47. This fisherman is wearing sunglasses. Without them, the glare off the water’s surface
would be too intense to see the fish.
48. These sunglasses are specially designed to filter light. They are called polarizing
sunglasses.
49. Polarizing filters, including sunglasses, have many tiny parallel slits that have the
ability to reduce vibrating light that contributes to glare.
50. They kind of act like venetian blinds, with many parallel slits allowing planes of light
to pass through.
51. The light that passes through polarizing filters is called polarized light.
52. Notice how the polarized light that has passed through the filter is vibrating along a
single plane. This helps reduce glare.
53. Graphic Transition - Light Interactions
54. As we already mentioned, light can be absorbed or reflected. Look at the shape of
this pencil as it passes down into the glass of water.
55. You Decide!
What property of light causes this pencil to look as if it is bending?
Visual Learning Company 1-800-453-8481
12
Using Light
Script
56. The answer is refraction. The property of light that makes objects look
differently in water is called refraction.
57. Refraction occurs when light passes from one medium to another. As light
passes from air into water, it slows down, causing it to bend when it strikes the
surface at an angle.
58. The bending of light causes the pencil to appear as if it is bent.
59. Refraction also causes objects under water to look bigger . . .
60. . .. than they actually are.
61. Diffraction is another property of light. Diffraction is the bending of light waves
around the edge of an object.
62. The process of diffraction is similar to the water in this stream bending around this
rock.
63. Diffraction is part of the reason you see the lights of an oncoming car before you
actually see the car.
64. Diffraction also is part of the reason the morning sky appears lit before the sun
actually rises over the horizon.
65. Graphic Transition - Reflection and Mirrors
66. This smooth lake surface shows a near perfect image of the bird flying over it.
67. And the rear view mirror in this car helps the driver to see what is behind her.
68. These objects are reflecting light. As we already mentioned, reflection occurs when
a wave hits an object and then bounces off it.
69. Light behaves like a ball bouncing on a flat surface.
70. When a ball hits a surface head on at a right angle, it bounces back in a straight line.
71. But if it hits at an angle, it bounces away at an equal angle.
72. Light behaves in a similar way.
73. For example, when light from this laser light hits this mirror at an angle, it bounces
or reflects away at an equal angle.
74. The light rays approaching a surface are called incident rays . . .
75. . . . and the light rays bouncing off a surface are called reflected rays.
76. The angle at which light strikes an object is called the angle of incidence.
77. And the angle at which light bounces off an object is called the angle of reflection.
78. The Law of Reflection states that the angle of incidence and the angle of reflection
are equal to each other.
79. Light, however, does not always reflect regularly, as we have just seen.
80. Regular reflection only occurs on very smooth surfaces, such as mirrors.
81. In most cases, a type of reflection called diffuse reflection occurs.
82. Most objects have an irregular surface. This brick wall, for example, when viewed
closely, has many bumps and pits.
83. When light strikes surfaces like these, it is scattered irregularly.
84. The atmosphere scatters light from the sun diffusely.
Visual Learning Company 1-800-453-8481
13
Using Light
Script
85. This is because the atmosphere is filled with gases and dust particles that
scatter light, allowing us to see objects that are not directly hit by the sun’s
rays.
86. Graphic Transition - Mirrors and Light
87. There are a wide variety of mirrors.
88. Mirrors are categorized based on the shape of their surface.
89. They include plane mirrors, concave mirrors, and convex mirrors.
90. Let’s first take a look at mirrors that you are probably most familiar with - plane
mirrors.
91. A plane mirror has a perfectly flat surface.
92. The reflection of objects in a plane mirror appear their actual size and are right side
up.
93. However, the image is reversed.
94. Let’s take an example. If you raise your right hand while looking into a mirror, it
appears that the left hand of your reflection is raised.
95. Also, when you place words in front of a mirror, they are reversed.
96. You Decide!
Why is the word ambulance written backwards on the front of this ambulance?
97. It is written backwards so drivers can see the word correctly when they look in their
rear view mirror, and can then make room for the ambulance to pass.
98. Graphic Transition - Concave Mirrors
99. Have you ever seen your reflection in a spoon? A spoon is a type of concave mirror.
100. A concave mirror is a type of mirror in which the surface curves inward.
101. Concave mirrors are very useful in telescopes, helping to gather light from objects in
space.
102. Light rays coming in parallel to a concave mirror are reflected toward and through
the same point called a focal point.
103. In turn, light reflected by a concave mirror from a light source positioned at its focal
point reflects light rays parallel to one another.
104. Concave mirrors are useful in car headlights, helping to form a powerful light beam.
105. The same holds true in flashlights. Behind the bulb is a concave mirror.
106. The concave mirror helps to form a strong focused beam of light.
107. Graphic Transition - Convex Mirrors
108. Back to our spoon. If we flip the spoon over, it now forms a convex mirror.
109. A convex mirror curves outward.
110. In convex mirrors, the image appears smaller than the actual object.
111. Quite often the side mirrors on cars . . .
112. . . . and motorcycles are convex mirrors.
113. They are useful because they provide a wide field of view.
Visual Learning Company 1-800-453-8481
14
Using Light
Script
114. You may even have seen convex mirrors in stores so that store
employees can see down aisles.
115. Graphic Transition - Concave and Convex Lenses
116. This thin piece of glass is a lens. Lenses are used in a variety of objects
such as eyeglasses.
117. Other lenses, such as these, are used in cameras.
118. A lens is a transparent material that bends light.
119. Most lenses, such as this camera lens, are made of glass or...
120. . . . plastic.
121. There are two main kinds of lenses - concave lenses and convex lenses.
122. Concave lenses are thinner in the middle and thicker at the edges.
123. Convex lenses are thicker at the center than at the edges.
124. This magnifying glass uses a convex lens and makes objects appear larger than they
actually are.
125. Graphic Transition - Summing Up
126. During the past few minutes we have explored many of the different properties of
light.
127. We have seen how objects reflect light,. . .
128. ...and absorb light,...
129. ...as well as how light can be refracted or...
130. . . . diffracted.
131. We also took a look at the characteristics of concave mirrors . . .
132. . . . and convex mirrors,...
133. ...as well as concave and convex lenses.
134. So the next time you notice the color of an object or use a mirror, think about the
properties of light. You just might think about light a little differently.
Video Quiz
Fill in the correct word when you hear this tone _______. Good luck, and let’s get
started.
1. __________ is the process of light bouncing off objects.
2. ____________ objects allow light to easily pass through them.
3. ___________ objects absorb most light.
4. ___________ reflects all the colors of the spectrum.
5. _________ filters reduce glare.
6. The process that causes the pencil to look as if it is bending is __________.
7. Light rays approaching an object are called _________ rays.
8. A _________ reflection occurs off an irregular surface.
9. This is an image of a _____ mirror.
10. Convex mirrors provide a ________ field of view.
Visual Learning Company 1-800-453-8481
15
Using Light
Answers to
Student Assessments
Preliminary Test
1. transparent
2. refraction
3. diffraction
4. absorbed
5. concave
6. reflection
7. opaque
8. diffuse
9. plane
10. shiny
11. true
12. false
13. true
14. true
15. false
16. true
17. true
18. false
19. false
20. true
Video Quiz:
1. reflection
2. transparent
3. opaque
4. white
5. polarizing
6. refraction
7. incident
8. diffuse
9. concave
10. wide
Post Test
1. false
2. true
3. false
4. true
5. true
6. true
7. false
8. true
9. true
10. false
11. diffraction
12. transparent
13. shiny
14. refraction
15. opaque
16. reflection
17. absorbed
18. plane
19. concave
20. diffuse
Video Review
You Decide:
A. reflection
B. Plastic wrap is transparent, while wax
paper is translucent.
C. refraction
D. The word is written backwards so that
drivers can read it when they look in their
rearview mirrors, allowing them to make
room for the ambulance to pass.
Visual Learning Company 1-800-453-8481
16
Using Light
Answers to Student
Activities
.
Understanding Optics
1. Eye specialists use the principles of
refraction to determine how much more
or less light rays need to be bent in order
for vision to be clear. This measurement
helps to determine the prescription of the
lenses.
2. Nearsightedness results when light
rays focus before meeting the retina.
This affects the ability to see distant
Reappearing Pennies
Conclusions: Refraction causes the penny to objects, but close objects remain clear.
reappear. The water slows the light and bends 3. Farsightedness results when light rays
it, allowing the penny to be seen. The penny reach the retina before focusing. This
affects the ability to see close objects, but
also appears larger because the water bends
distant objects remain clear.
the light. The penny near the back of the
4. Nearsightedness - Diagram A
glass looks larger because the light must
Farsightedness - Diagram B
travel through more water, creating a larger
5. concave
image.
6. convex
7. Answers will vary.
Flashlight Physics
Mirror Images
Conclusions: In the convex mirror, the tree’s
reflection is upright and smaller. If the tree’s
reflection in the concave mirror is upright
and larger, the reflection is within the focal
point. If the reflection is upside down and
smaller, it is beyond the focal point. Answers
will vary.
Conclusions: In step 4, the distances should
be relatively equal. The distances would not
be equal if the students were of different
heights. In step 5, the partner with the
flashlight will be closer to the mirror than his/
her partner. It is not possible to produce a
strong, reflected beam of light with the
aluminum foil. This is because uneven
surfaces scatter light, resulting in diffuse
reflection. The ball would not bounce off at
the expected angle and would therefore miss
its target.
Vocabulary Lesson
1. diffraction, g
2. translucent, c
3. concave, d
4. polarizing, j
5. lens, i
6. refraction, e
7. reflection, a
8. convex, f
9. incidence, h
10. transparent, b
Visual Learning Company 1-800-453-8481
17
Assessment
and Student
Activity
Masters
18
Using Light
Name___________________
Preliminary Test
Directions: Fill in the blank with the correct word. A list of
possible answers is provided at the bottom of the page.
1. Materials such as glass and water are _________, allowing most light to
pass through them.
2. __________ occurs when light passes from one medium to another,
causing the light to speed up or slow down.
3. _________ is the bending of light waves around the edge of an object.
4. Black is produced when all the colors of the spectrum are _________.
5. _________ lenses are thinner in the middle and thicker at the edges.
6. The angle at which light bounces off an object is called the angle of
_________.
7. _________ objects tend to absorb some light and reflect the rest.
8. In _________ reflection, light is scattered after hitting irregular surfaces.
9. A ________ mirror has a perfectly flat surface.
10. _________ surfaces reflect a large amount of the light that strikes
them.
shiny
transparent
opaque
refraction
diffraction
reflection
absorbed
plane
concave
diffuse
incidence
convex
19

Using Light
Name___________________
Preliminary
Test
Directions: Decide whether the answer is True (T) or False (F).
11. Reflection is the process of light bouncing off objects. T
F
12. Opaque objects allow most light to pass through
them.
T
F
13. Leaves do not absorb most green light.
T
F
14. White reflects all of the colors in the spectrum.
T
F
15. Refraction causes objects under water to appear
smaller than they actually are.
T
F
16. The Law of Reflection states that the angle of
incidence and the angle of reflection are equal to
each other.
T
F
17. The image in a plane mirror is reversed.
T
F
18. In convex mirrors, the image appears larger than the
actual object.
T
F
19. Concave lenses are thicker in the middle and thinner
at the edges.
T
F
20. After passing through a filter, polarized light vibrates T
along a single plane.
F
20

Using Light
Name___________________
Video Review
Directions: During the course of the video, answer the “You Decide”
questions as they appear. Answer the Video Quiz questions at the end of
the video.
You Decide:
A. What’s the term used to describe the process
of light bouncing off objects?
Answer: _______________
B. What is the difference between this plastic
wrap and this wax paper?
Answer: _______________
C. What property of light causes this pencil to
look as if it is bending?
Answer: _______________
D. Why is the word AMBULANCE written
backwards on the front of this ambulance?
Answer: _______________
Video Quiz:
1. ___________ is the process of light bouncing off objects.
2. __________ objects allow light to easily pass through them.
3. __________ objects absorb most light.
4. __________ reflects all the colors of the spectrum.
5. __________ filters reduce glare.
6. The process that causes the pencil to look as if it is bending is __________.
7. Light rays approaching an object are called __________ rays.
8. A __________ reflection occurs off an irregular surface.
9. This is an image of a __________ mirror.
10. Convex mirrors provide a __________ field of view.
21

Using Light
Name___________________
Post Test
Directions: Decide whether the answer is True (T) or False (F).
1. Concave lenses are thicker in the middle and
thinner at the edges.
T
F
2. Leaves do not absorb most green light.
T
F
3. Opaque objects allow most light to pass
through them.
T
F
4. After passing through a filter, polarized light
vibrates along a single plane.
T
F
5. White reflects all of the colors in the spectrum.
T
F
6. The image in a plane mirror is reversed.
T
F
7. Refraction causes objects under water to
appear smaller than they actually are.
T
F
8. Reflection is the process of light bouncing off
objects.
T
F
9. The Law of Reflection states that the angle of
incidence and the angle of reflection are equal to
each other.
T
F
10. In convex mirrors, the image appears larger
than the actual object.
T
F
22

Using Light
Name___________________
Post Test
Directions: Fill in the blank with the correct word. A list of
possible answers is provided at the bottom of the page.
11. _________ is the bending of light waves around the edge of an
object.
12. Materials such as glass and water are _________, allowing most light to
pass through them.
13. _________ surfaces reflect a large amount of the light that strikes
them.
14. __________ occurs when light passes from one medium to another,
causing the light to speed up or slow down.
15. _________ objects tend to absorb some light and reflect the rest.
16. The angle at which light bounces off an object is called the angle of
_________.
17. Black is produced when all the colors of the spectrum are
________.
18. A ________ mirror has a perfectly flat surface.
19. _________ lenses are thin in the middle and thick at the edges.
20. In ________ reflection, light is scattered after hitting irregular surfaces.
shiny
transparent
opaque
refraction
diffraction
reflection
absorbed
plane
concave
diffuse
incidence
convex
23

Using Light
Name___________________
Mirror Images
Objective: In this lab you will learn about the properties of plane, convex,
and concave mirrors.
Background: Mirrors are an important part of our everyday lives. They enable us to
drive our cars safely, check our appearances, and view the stars. Most of the mirrors that
hang on the walls of our homes are plane mirrors. Plane mirrors are perfectly flat,
producing images that are upright and the same size as the object. The images, however,
are reversed. For example, if you blink your right eye when looking in a mirror, it
appears as though the left eye of your reflection is blinking. But not all mirrors produce
these types of images. As you have learned, the size and orientation of the reflected
image depends on the shape of the mirror. A mirror that curves outward is a convex
mirror, bending the light so that the image is upright and smaller than the actual object.
Convex mirrors widen our field of vision and are therefore used in rearview mirrors. A
mirror that is curved inward, like a spoon, is a concave mirror. The distance between
the object and mirror determines the size and orientation of the image. Light rays coming
in parallel to a concave mirror are reflected through the same point, called the focal
point. If the object is within the focal point, the image appears upright and is larger than
the object. If the object is located beyond the focal point, the image appears upside down
and smaller than the object. Concave mirrors are used in telescopes to gather light from
objects in space, thus allowing us to see things that are invisible to the naked eye.
Materials:
Concave mirror
Convex mirror
Plane mirror
Sheet of paper
Pen or pencil
Directions:
1. Send a coded message to a classmate. Write a word or message that
can only be read by seeing its reflection in a plane mirror. This is tricky, so practice
to see which way the letters need to be oriented in order for their reflection to be
readable.
2. Draw a picture of a tree on a separate sheet of paper.
3. Hold the drawing in front of a convex mirror. Record the size and position of
the tree’s reflection.
4. Repeat Step 3 using a concave mirror..
Conclusion: How did the tree appear in the convex mirror? How did it appear in the
concave mirror? Based on its appearance in the concave mirror, was the tree located
within or beyond the focal point? Brainstorm a list of five different everyday uses of
mirrors. Determine whether the mirrors are concave, convex or plane mirrors.
24

Using Light
Name___________________
Reappearing Pennies
Objective: In this lab you will observe the refraction of light.
Background: Did you know that objects underwater, such as fish or
seashells, are actually smaller than they appear? This occurs because of refraction.
Refraction is the same phenomenon that causes a pencil partially submerged in
water to appear as if it is bent. Refraction, or the bending of light, occurs when
light passes from one medium to another. When travelling through air, light
moves at a constant speed.The speed of light waves decreases when they enter a
substance of a different density, causing them to bend. After passing through the
material, the light rays return to the original speed and direction in which they
were traveling before encountering the denser material. Refraction is part of our
everyday lives - it is what enables eyeglasses and contacts to correct vision, and
causes prisms to produce beautiful rainbows of colors.
Materials:
Penny
Opaque cup
Dry erase marker
Clear glass filled with water
String
Tape
Directions:
1. Your teacher will divide you into groups of two.
2. Place the penny in the opaque cup.
3. Keeping your eye on the penny, have your partner slowly move the cup away
from you. Tell him or her to stop once you can no longer see the penny.
4. Have your partner slowly pour water into the cup. Tell him or her to stop when
the penny reappears.
5. Switch places with your partner. Repeat steps 3 & 4.
6. Tie a piece of string around a penny. Secure it with a piece of tape if
necessary.
7. Submerge the penny in the clear glass filled with water. Place it near the front
of the glass.
8. Looking through the side of the glass, draw the image of the penny on the
glass. Compare your drawing to a penny that is not submerged in water.
9. Now place the penny toward the back of the glass. Repeat step 8.
Conclusion: What property of light causes the penny to reappear? Explain why
this occurs. In step 8, does the penny appear larger or smaller than an actual
penny? Why does this occur? Which produces a larger image of the penny,
placing it near the front or the back of the glass? Explain.
25

Using Light
Name___________________
Flashlight Physics
Objective: In this lab you will learn about the Law of Reflection.
Background:
Have you ever watched someone play pool and been amazed by some of
the shots they can make? When there is no clear shot, it is often necessary to
bounce the ball off the side walls of the pool table. One of the secrets to
becoming a pool shark is to know that the ball will bounce off the wall at the
same angle at which it hit the wall. This is similar to the reflection of light. As
you know, reflection is the process of light bouncing back. The angle at which
light hits an object is called the angle of incidence, while the angle at which light
bounces off an object is called the angle of reflection. According to the Law of
Reflection, the angle of incidence equals the angle of reflection. The angle at
which light bounces off the surface is equal to the angle at which it hits the
surface, following the same rule as the pool ball.
Materials:
Flashlight
Meter stick
Mirror (at least 6 x 6 inches)
Piece of aluminum paper (same size)
Directions:
1. Your teacher will pair you with a classmate of the same height.
2. Stand 2-3 feet away from your partner, facing him or her.
3. Place a mirror on the floor between you and your partner. Turn off the lights.
4. One partner should hold the flashlight by his or her nose and shine it on the
mirror. The partner with the flashlight should move back and forth until the
reflection of the beam hits the other student’s nose. Measure the distance each
student is standing from the center of the mirror.
5. Repeat Step 4 after switching roles. This time, the student with the flashlight
should be on his or her knees, while the other student remains standing. Once
the light has hit the partner’s nose, measure how far each student is from the
mirror.
6. Replace the mirror with a piece of aluminum foil that has been crumpled and
unfolded again (but not smoothed). Repeat Step 4.
Discussion:
Compare the distance each partner stands from the mirror in Step 4. Would the
distances be different from one another if the shortest and tallest students were
paired together? How do these distances compare in Step 5? What happened
when you replaced the mirror with the wrinkled aluminum foil? Discuss with
your partner why you think this occurred. What would happen to a pool ball if a
manufacturing flaw in the pool table produced a bump on the side wall?
26

Using Light
Name___________________
Understanding Optics
Objective: In this lab you will learn how different properties of light
affect vision.
Directions: Answer the questions based on the information provided below.
Background: Have you ever wondered how your eyes enable you to see? You
may be surprised to discover that many of the light properties that you have
learned about play an important role in vision. For those with so-called perfect
vision, light rays enter the eye and converge, or focus, at a point directly on the
retina, which is the tissue lining the back of the eyeball. This can be seen in the
diagram below.
Retina
However, only 40% of the population has perfect vision. This means that if you
have a group of ten people, only four of them will be able to see perfectly
without the aid of glasses or contact lenses. The other six people will have an eye
disorder, such as nearsightedness or farsightedness. Eyeglasses, contact lenses, or
corrective surgery enable people to see clearly despite these disorders.
Nearsightedness, or myopia, means that you can see objects which are close but
not objects at a distance. This occurs when the eyeball is too long from front to
back, causing light rays from distant objects to focus before reaching the retina.
When light rays finally reach the retina, they produce a blurred image.
Nearsighted people are able to clearly see distant objects with the aid of concave
lenses. Concave lenses are thinner in the middle than at the edges, causing them
to bend the light rays outward so that they focus on the retina.
27

Using Light
Name___________________
Understanding Optics
(cont)...
Farsightedness, or hyperopia, means that you can clearly see distant objects but
not objects at a close range. This occurs when the eyes are too short. If there were
no physical barriers, light rays would converge behind the retina. Although this is
not physically possible, the light rays strike the retina before they are brought in
to focus, making close objects appear blurred. The ability to see close-range
objects can be improved with convex lenses, which are thicker in the middle than
at the edges. Convex lenses bend the light rays inward, enabling them to focus on
the retina, making close-range objects appear clearly.
Fortunately, people with eye disorders are able to see clearly with the aid of eye
glasses or contact lenses. The lenses of eyeglasses are ground to form either
concave or convex lenses, although it is often necessary to use a combination of
the two. Many people have blurred vision when viewing both distant and
close-range objects. These people rely on bifocal or trifocal lenses to see clearly.
The lenses of bifocal glasses are assembled so that they have both convex and
concave parts, one on top of the other. Trifocals have a center part that allows you
to see intermediate distances. Many people find it convenient to wear contact
lenses, which are plastic corrective lenses. They are held in place by a thin layer
of tears on the eye’s surface. Although it appears as though contact lenses have a
dramatic concave shape, they can be either concave or convex lenses, thus
enabling both nearsighted and farsighted people to see clearly.
So how do you find out if you have an eye disorder? Many people go to an eye
specialist for an eye exam. During the part of the exam known as refraction, your
eye specialist measures how much more or less each eye needs to refract light rays
so that they focus on the retina. This measurement helps the specialist determine
your eye prescription. As you can see, your vision is just one of the many ways
that light makes a difference in your everyday life.
Questions:
1. How does the refraction of light affect vision?
2. What happens if your eye is too long from front to back?
3. What happens if your eye is too short from front to back?
28

Using Light
Name___________________
4. Look at the diagrams below. Which is the eye of a farsighted person
and which is the eye of a nearsighted person?
Diagram A
Diagram B
5. Imagine that you are an eye specialist. What type of lens would you prescribe
to someone with the eye in diagram A?
6. What type of lens would you prescribe to someone with the eye in diagram B?
7. Write a paragraph describing how your life would be different if you had an eye
disorder and glasses and other visual aids had not yet been invented.
29

Using Light
Name___________________
Vocabulary of
Using Light
Directions: Unscramble the following vocabulary words and match each
word with its correct definition.
___ 1. ffradiction
a. the process of light bouncing off
objects
___ 2. lucnetsnart
b. material that allows most light to
pass through it
___ 3. nocceav
c. most plastics are an example of this
type of material
___ 4. zingiralop
d. type of mirrors found in telescopes
and car headlights
___ 5. slen
e. the bending of light as it passes
through different mediums
___ 6. fracretion
f. the type of lens used in
magnifying glasses
___ 7. lectnoiref
g. the bending of light waves around
the edge of an object
___ 8. xvenoc
h. the angle at which light strikes an
object
i. a transparent object that bends light
___ 9. dicinence
j. a type of filter that reduces glare
___ 10. paresnartnt
30
