Grade:
Time:
Topic:
Concept:
SOL: Science:
Rationale:
Goals:
Cognitive Objective:
The student will be able to distinguish, on a short quiz, the work of cones within the eye by answering 4 out of 5 true or false questions correctly.
The child will create his or her own picture that would cause an afterimage to appear.
The child will predict the colors that will be seen in any given afterimage with 2 out of 3 possibilities correct.
The child will accurately predict 3 of 4 colors of an afterimage.
Affective Objective:
The student will choose materials and colors that are personally important or interesting as he or she creates a diagram.
The child will recognize the significance of peers’ work in the learning environment.
Psychomotor Objective:
The student will use his or her fine motor skills when creating a diagram.
The child will exercise hand-eye coordination as he or she carries out short experiments.
Materials:
Poster board
A book about light (Eyewitness Books has several to choose from.)
Paper
A book about sight (How Do Our Eyes See? Is a good example.)
Markers
Chalk
Paint
Small paper or plastic cards
Procedure:
Advance Organizer: Pass out small cards with a picture of the American flag on them. In place of the red, the stripes should be green. Instead of blue, the field in the upper left hand corner should be yellow. The stars should be blue, and the previously white stripes should be blue, as well.
Each child should stare intently at his or her flag card and then immediately look at a blank sheet of white paper when the teacher gives the signal. The student will be amazed to see a red, yellow, and blue afterimage on the white surface.
Ask the children, “What could have made our eyes see the flag, in completely different colors, on the white paper?”
Encourage the children to share their ideas
Introduce the term cone. Cones are inside our eyes, and they allow us to sense color. Draw a diagram of the human eye on the board, and point out the location of cones in our eyes. (On the retina.) Tell the children that there are 6.5 million cones in their eyes, and that because of all of those cones, the human eye can see 10,000,000 colors!
Because there are only three types of cones (red, blue, and yellow sensors), we can do tests like the afterimage flag. Sometimes, after a person has stared at an object for too long, that person’s cones become overloaded, or tired. When the person looks away, the message the cones send to the brain becomes altered quickly, which causes a person to see the complementary color of the color he or she was examining.
Cones send color messages to our brains, and our brain mixes the colors together so that we see so many different colors and shades.
Diagram the complementary colors on the board with the students’ help.
Red-Green
Blue-Yellow
Yellow-Blue
Assign the children the task of choosing an object, coloring it on a sheet of paper using its complementary colors, and then testing its afterimage out for themselves when they are finished. For example, a student might color a large green apple with a red leaf on its stem. The afterimage should look like a large red apple with a green leaf on its stem.
Closing:
Allow children to look at several of their classmates’ drawings and predict what the afterimage for each will look like. Ask all of the students to help clean up.
Assessment:
Using a class list rubric, individually assess each student’s ability to predict the colors of an anticipated afterimage.
Administer a short, written true or false quiz.
1. The complementary color of blue is yellow. T
2. The complementary color of red is blue. F
3. People have millions of cones inside their eyes. T
4. We can only see 3 colors with our eyes. F
5. If a person is color-blind, his or her cones work well. F