WOULD YOU BELIEVE YOUR EYES?
Grades 7 - 9
This is a lesson designed to review the parts of the human eye
and understand how the eye and the mind work together to form optical illusions.
This lesson can cross the science curriculum into art, math, language arts,
drama and careers, to name a few.
Students will be actively involved studying the parts of the human eye and
identifying their functions, looking at and creating unique optical illusions,
developing a hypothesis for the existence of optical illusions and questioning
an eye doctor as a guest speaker.
Students will create dodecagons which are twelve-sided figures with twelve
equal angles and share these with the class so that each student can begin
to see how many different illusions can be created within the same set of
The length of this lesson can run anywhere from 2-5 class periods depending
on the number of Extension Activities and Action Plans utilized.
READING RAINBOW #801: "Opt.. An Illusionary Tale"
At the end of this lesson the student should be able to:
- Define the parts of the human eye and optical illusion.
- Identify and describe the five main categories of optical illusions.
- Develop unique optical illusions in cooperative groups.
- Differentiate between two leading theories of optical illusion (Perspective
and Previous Experience).
- Write a hypothesis and/or theory explaining individual thoughts on
- Draw "disappearing railroad tracks" and identify vanishing
points and horizontal lines.
- Identify Trumploi optical illusions through paintings.
- Explain the three main types of practical optical illusions.
- One teacher copy of each attached overhead.
- One copy of the human eye worksheet per student.
- One 12 inch ruler per student.
- Several sheets of 8 1/2 x 11 typing paper per student.
To immediately focus student attention ask, "Who can name
any part of the human eye?" List all of their answers on the board
or overhead. Because most students will not know the answers you might want
to do some prompting here.
"O.K., I have a picture of the human eye on the overhead with a list
of eye parts and I would like you to raise your hands and tell me where
to place these names on the picture." Have the students come up to
the overhead and actually write in their answers.
After filling in all of the blanks on the overhead, hand out a copy of the
eye to each student and have the students fill in the correct words so that
they will each have an accurate copy of the human eye. "Please copy
the correct answers from the overhead to your diagram so that you will have
an accurate study sheet."
Hand each student a vocabulary sheet and have the students write in the
definitions following a short discussion of each term. "Here is a list
of vocabulary words concerning the human eye. I will choose a term on the
sheet and call on one of you to give an educated guess as to its particular
function. Susan, what is the purpose of the retina? Yes, everyone please
copy down this definition for retina. . . ."
Continue calling on the students until all of the terms have been defined.
"Now that we know the parts of the eye and their functions, who can
define optical illusion? Good, John, optical illusions are visual tricks
that are played on the mind."
"Who can tell me a specific optical illusion you have seen? I'll start
you off with the old lady, young lady. Now, who else has one?" Begin
a brainstorm list on the overhead, writing down all appropriate answers.
"Later in the week we'll have an eye-doctor come as a guest speaker
to explain and show how the human eye works and why we see optical illusions."
"Right now we are going to watch a video called, "Opt. . .An Illusionary
Tale" about optical illusions. I'm going to have each of you watch
and listen for several key items so. . .let your eyes and ears do the talking."
To give the students a specific responsibility while viewing:
Ask students to listen for the definition of horizontal line.
Ask students to listen for the definition of vanishing point.
Ask the students to identify four tools of a TrumpLoi artist.
Instruct students to raise their hands once they hear the answers for the
BEGIN the video where LeVar Burton is holding a spinning red and
white bull's eye. This is after he shows how to make an indoor snow storm.
PAUSE the video on the picture of two cats on the fence. Let students
really look at the painting and begin showing them all of the parts of the
painting that look so real. This is a precursor for the next pause point
when TrumpLoi is defined. RESUME the video.
PAUSE the video on the picture of jewelry to let the students write
the definition for TrumpLoi (French word for, trick the eye). Students should
have raised their hand for you to pause here. RESUME the video.
PAUSE the video on the close-up of the blackbird. Ask the students
what really makes the bird look real. (You should get responses regarding
shading, shadow, three-dimensional etc.) Ask the students if they have seen
any paintings like this and lead a discussion accordingly. RESUME
PAUSE the video on the Horizon Line Definition so that the students
can copy this definition in their notes. The students should have raised
their hands here. RESUME the video.
PAUSE the video on the Vanishing Point Definition so that the students
can copy this definition in their notes. This also comes from the Focus
For Viewing section. RESUME the video.
PAUSE the video when the guest artist says, "Here's a pair of
railroad tracks that are going to disappear right into the horizon."
At this point hand each student a piece of typing paper and have them take
out a ruler and pencil so that they can draw the railroad tracks right along
with the artist on the video. At this point the teacher must pause the video
according to the students' speed of drawing and some rewinding might need
to be done to insure that all students are accomplishing disappearing tracks.
RESUME the video.
PAUSE the video when the guest artist says, "The railroad tracks
get closer together. . ." Have the students continue drawing the tracks,
copying the video picture. RESUME the video.
PAUSE the video when the artist says, "We could add telephone
poles. . ." As the students draw the telephone poles, help them connect
the vanishing points. Rewind the video until all students have finished.
RESUME the video. PAUSE the video when the artist says, "Creating
illusion of distance. . ." Have the students look at their own drawing
and compare with the video. Have several students share their artwork with
the class, continuing to stress vocabulary words. Ask the students what
creates this illusion. RESUME the video.
PAUSE the video when the artist says, "Most important tool of
all is imagination." Discuss with the students the importance of imagination
and art and optical illusions. RESUME the video (Let the next video segment
continue without interruption).
PAUSE the video when the artist says, "Is basically what fools
the viewer." Discuss with the students any thoughts of how real the
door handle looks. RESUME the video.
PAUSE the video on the picture of the shutter doors. Ask the students
about how real the shutter door looks and what causes the mind to think
it is real. RESUME the video.
PAUSE the video on the picture of the lights of the ferris wheel.
Have the students guess how this was accomplished. RESUME the video
for the answer. STOP the video when LeVar Burton comes back into
After viewing the video and making general comments the students
will take notes and discuss the five major categories of Optical Illusions,
while viewing samples of each one.
Using the overhead titled Categories of Optical Illusions, have the students
copy these definitions into their notes and show examples of each category.
These examples can be found in any book about optical illusions or you may
use the bibliography at the end of this lesson. Discuss each category thoroughly.
Then, split the class into five small groups representing each of the five
main categories of optical illusion. Each group must create their own illusion
using all of their newly gained knowledge. Their illusions must be backed
up with a unique hypothesis explaining why their new illusion tricks the
mind. The students may include in their hypotheses things such as: functions
of the eye, perspective, experience, color, etc.
Give each group no more than two class periods to complete this task. After
all illusions have been created have the groups present their findings to
the class and lead a discussion following each presentation. During this
part of the lesson you might want to review vocabulary, look at specific
examples, re-watch parts of the video, etc.
Next, to assess student learning I have the students write a one-two page
essay answering the question, "What is Optical Illusion?" The
students are allowed to use their notes and any visual aids that they have
such as books, articles or pictures of optical illusions. This evaluation
really lets the students state their opinions and it gives them a chance
to back up their thoughts with their notes.
Finally, to bring in the math side of illusions have the students create
dodecagons in the following manner.
Ask the students, "Does any one know what the root word for twelve
is? If you can think of a math term it might help. Yes, Bob, dodeca means
twelve and a dodecagon is a twelve-sided figure with twelve equal angles.
Now then, Karen, tell me how you think a dodecagon ties in with optical
illusions. Yes, if dodecagons are created as symmetrical figures with shading
they become optical illusions because it's difficult to tell where each
individual dodecagon begins and ends. And, if you change the pattern slightly
the illusion completely changes."
At this point, hand the students a copy of the 63 dodecagons worksheet and
discuss with the students the different patterns and have them first draw
one that is listed and finally, have each student create a new repeating
dodecagon that creates an illusion of some sort.
First, have the students each draw a twelve-sided outline that is fairly
large so that they will have room to work. Next, have each student begin
drawing a dodecagon that is from the worksheet so that they begin to see
what makes a dodecagon turn out equal. Remind students that they may only
use straight lines although the lengths may vary. Walk around and assist
students as necessary.
When students have completed this dodecagon, have them begin creating their
own design within a twelve-sided figure. Tell the students that their design
must be repeated in at least 10 connected dodecagons so they should create
a center design that is repeatable. Also, it is recommended that students
either color their dodecagons or shade them in with pencil so that the illusion
in more noticeable.
After all of the students have finished this assignment, have them share
their creations with the class so that each student has a chance to see
the different illusions developed with the same twelve-sided boundary.
- Take a field trip to a zoo, museum and a city to identify illusions
of camouflage, art and architecture.
- Create school signs that are readable by the colorblind after having
a guest speaker explain color blindness.
- Invite a local illusionist to speak to the class about theories in
his/her field and then as follow-up have students write a letter of thanks.
- Use the Internet to gain information about illusionists and write
to them asking for opinions and information about their tricks.
- Invite an architect to show how buildings often have illusions for
- Use the math concepts of positives and negatives to make shadow tracing,
- Use the computer lab to create computer-generated illusions using
painting programs as well as CAD (Computer Aided Drafting).
- Invite an eye doctor to explain different careers working with the
- Work with the school art department to create mural-sized illusions
to hang around the school.
- Write a letter to one of the leading illusionists agreeing or disagreeing
with their theories.
Kettelkamp, Larry. Tricks of Eye and Mind. William Morrow and Company. New
York. 1974. Mueller, Conrad, G. and Mae Rudolph. Light and Vision. Time
Science Library. New York. 1966.
Simon, Seymour. The Optical Illusion Book. Four Winds Press. New York. 1976.
Ward, Brian W. The Eye and Seeing. The Human Body. Franklin Watts Limited.
Wertenbaker, Lael. The Eye: Window to the World. Torstar Books. New York.
Lesson plan created By Kendra Ruwe Clark, Lowell Scott
Middle School, Meridian, Idaho
Lesson Plan Database
Thirteen Ed Online