Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

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Private Universe Project in Science

Workshop Five: "Can We Believe Our Own Eyes?"

Section 1 - About Workshop Five:
"Can We Believe Our Own Eyes?"


This video is currently not available.

What is the theme of this workshop?
The theme of Workshop Five is "the origins of student ideas."

Whom do we see in the video?
Richard and Karen, eighth graders, and Conor, a fifth grader, are three students who constructed many of their ideas from personal experience, television nature specials, and classroom activities. Conor blends the various resources and constructs rich and imaginative explanations of light and vision; Richard vacillates between scientific and non-scientific ideas, even after instruction; and Karen never waivers from her personal construction about vision.

What happens in the video?
Students of various ages discuss their ideas of how we "see." Their ideas, many of which seem to come from sources outside of school, often differ from those accepted by scientists. Where do students' ideas come from and can (or should) they be changed?

What problem does this workshop address?
Although mirrors are among the most common of scientific devices, they remain enigmatic. The average adult in the United States may use a mirror 30,000 times in a lifetime. Why is it that, even with all of this experience, so many adults still cannot answer simple questions about the properties of mirrors?

"Can We Believe Our Own Eyes?"
addresses students' "conceptual change," a process by which students replace old ideas when new ones become more acceptable. This workshop explores how students construct ideas from the many sources available to them. Television, radio, books, parents, teachers, and peers all play a role in promoting the ways in which students see and understand natural phenomena. In contrast, seeing often contradicts their understanding and, as a result, seeing is not always believing. What can we learn about children's concepts of light and vision that can shed some light on this problem?

What teaching strategy does this workshop offer?
The role of students' experience can be very powerful in shaping their ideas and beliefs. Does this experience always lead to a better understanding? Teachers learn to confront students' understanding by offering alternative experiences that contradict old ideas.


Section 2 - "Can We Believe Our Own Eyes?"

A. The Goals for Workshop Five

"Can We Believe Our Own Eyes?" is for teachers and educators who want to recognize and understand the process by which students begin to replace old ideas when new ones become more plausible. This process, called conceptual change, can be difficult and confusing for students. For a time, students may hold both the old and new ideas, switching back and forth between them in different contexts. Understanding conceptual change is an important tool for teachers of all grade levels.


Workshop Discussion

Do you think it is possible for a teacher to control the way a student interprets ideas? Please explain your response.

B. Challenges

When teachers see their students espousing non-scientific ideas picked up from television, books, and other sources, often the immediate reaction is to suggest ways to eradicate the sources of "misconceptions" and replace the alternative ideas with the science ideas.

The more experience we have with something, the more difficult it can be to understand. Experience can reinforce or create misconceptions. Experience does not equal understanding.

Should or can we as educators "misconception-proof" the student's world? Explain.


Workshop Discussion

After viewing Dr. Sadler's interview with high school students:
Talk about times when you have provided evidence in the form of a demonstration or lab activity and your students still didn't believe the implications derived from that evidence.
After viewing Conor's interview about how animals see: Where do Conor 's ideas fit into the scheme of common ideas?

Section 3 - Exercises

A. Exercise: Responding to Workshop Five


Workshop Activity

Light allows us to see and yet light itself seems invisible. What activities might we devise to help students in grades K-3 develop concrete images of the abstract concept of light?


B. Exercise: Preparing for Workshop Six

You will get the greatest benefit from Workshop Six if you complete the following exercise.


Pre-Workshop Activity

Ask friends or colleagues if it is possible to design a machine that will run forever. If they think it is possible, ask them to explain why and how. If not, ask them to explain why not.


C. Solution to Previous Week's Exercise

The problem posed for this workshop was: If a mirror is mounted flat against a wall, at least how long (or high) must it be for you to see your whole body in it? Does distance play a role in what you see?


Workshop Activity

Review the "Mirror..." video clip. Compare and discuss your journal predictions with what you have just seen about mirrors.


The Case of the Penny-Wise Architect Designing a Chain of Clothing Stores

"What is the shortest length of mirror (hung flat against a wall) that can show a body from head to toe?"

Answer at end of chapter.


Section 4 - Educational Strategy

A. Anchoring Examples and Bridging Analogies

Use of anchoring examples and bridging analogies are strategies that may be helpful when a student finds a concept especially implausible but thinks that a related concept is obviously true. The concept that the student already accepts becomes the anchoring example. The teaching task becomes to use lab activities, discussion, or other approaches to help the student build a bridge between the anchoring example and the target concept. The pieces of this bridge are called "bridging analogies."

Here is an example with vision for young children.

Many children believe that the role of light in vision is only to "light up" an object, making it visible. They have no idea that the light must be scattered from the object into the eye in order for vision to occur. Many of these children will say that light travels to an object from a light source, such as a lamp, and "just stays there." [Note: When light strikes a very smooth object, like a mirror, light is said to be reflected by the object: the light emerges in a "coherent" way as opposed to the helter-skelter scattering of incident light by rough objects. (Mirrors are good examples of the former, rugs of the latter.)]

The objective here is for children to build an understanding that some light is scattered from (or by) objects, rather than all of the light just stopping (i.e. being absorbed).

  1. First we look for an anchoring example of reflection or scattering that most children will readily accept. Many children will already believe that light reflects from mirrors. (You can question them as a group to determine this belief.) To help reinforce this understanding and to demonstrate mirror reflection to all of the children, let them play with mirrors. They can shine flashlights into wall mirrors and watch the spots of reflected light move across the opposite wall. Or they can hold small hand mirrors and make spots of light on the walls and ceiling by reflecting lamplight or sunlight. Perhaps several children together can make their spots of light "play tag."
  2. Question the students again about the reflection and scattering of light. Most of them will believe in mirror-reflection but not in scattering from other surfaces. Ask them if they think we can light up an object (say, an apple or a small toy) in an otherwise dark room by bouncing (reflecting) light from a mirror onto the object. If they say "yes" (most will), then ask them if we can light up the same object by scattering light from a piece of paper onto it. Emphasize that you are talking about plain, non-shiny paper. Many of the children will likely say that this lighting up of an object is not possible.
  3. Demonstrate the phenomenon in a darkened room, with a flashlight, a white piece of paper, and an object. Many of the children will see that light does scatter from a non-shiny object. Some will think that the white color of the paper is a special case, that light wouldn't scatter from paper of other colors. Use paper of other colors, preferably light colors like pink or yellow, to show that white light is indeed scattered from the colored paper. This demonstration may also provide an opportunity to begin an exploration of color and light.

In this activity, understanding that light is reflected by "shiny" objects is the target concept and the reflection of light from mirrors is the anchoring example. The demonstration of light scattered by paper (and thence illuminating other objects) provides the bridge.

As with any strategy, this activity will leave some children unconvinced. But those who now accept that light reflects from shiny objects are ready to begin constructing a concept of vision more like that of scientists.

Another Example of a Bridging Analogy

Target Concept: A table exerts an upward force on a book resting on the table.

Anchoring Example: We feel a spring "push up" as we push down on it.

Bridging Analogy: Pushing down on surfaces of various "springiness." For example: a foam rubber pad and a long flexible board supported at both ends.

(See Workshop Six, Section 4 for another example of a Bridging Analogy.)



Section 5 - Resources for Workshop Five


Companies, publications, and organizations named in this guide represent a cross-section of such entities. We do not endorse any companies, publications, or organizations, nor should any endorsement be inferred from a listing in this guide. Descriptions of such entities are for reference purposes only. We have provided this information to help locate materials and information.


A. Related Resources for the Classroom

For more information on materials that might be helpful in the classroom, contact the following sources:

Ardley, Neil. The Science Book of Color. San Diego, CA: Harcourt Brace Jovanovich, Inc. 1-800-543-1919.

Osborne, Jonathan, P. Black, M. Smith and J. Meadows. 1991. LIGHT. Primary Space Project Research Report, Liverpool University Press.

Burston Distribution Services
Unit 2A
Newbridge Trading Estate
Newbridge Close
Off Whitby Road
Bristol BS44AX
Tel: 011-441-272-7242-48
Fax: 011-441-272-711056

Children's Learning in Science

Center for Studies in Science and Mathematics Education, University of Leeds, Leeds LS2 9JT: Full Research Report on Light.

The Business Secretary
The University of Leeds
Leeds LS2 9JT

Light. TOPS Learning Systems

Inquiry based activities on light for upper elementary grades
TOPS Learning Systems
10970 South Mulino Road
Canby, OR 97013

Pieces and Patterns. (For grades 5-9) Fresno Pacific College, Fresno, California.

AIMS Foundation
PO Box 8120
Fresno, CA 93747

Optics. ESS Publications, Nashua, New Hampshire.

Uses simple materials to explore many concepts in the area of light.
Order from Delta Education
12 Simon Street
Nashua, NH 03060-3009
Fax: 1-800-282-9560

Light and Shadow: Nashua, New Hampshire: ESS Publications.

A unit for early primary grades in which children explore the origins and nature of shadows. Can be adapted for older children.

Order from Delta Education
12 Simon Street
Nashua, NH 03060-3009
Fax: 1-800-282-9560

Shapiro, Bonnie L. What Children Bring to Light. 1994. New York: Teachers College Press.

AIDC Distributor

Hammond, Ronald E. What About Human Vision?

Carolina Biological Supply Company
2700 York Road
Burlington, NC 27215


B. Further Reading

Bosak, Susan et al. 1991. Science Is... Ontario, Canada: Scholastic Canada, Ltd.

Cole, K.C. Vision: In the Eye of the Beholder. San Francisco, CA: Exploratorium.

Driver, Rosalind, Edith Guesne and Andree Tiberghien, eds. 1985. Children's Ideas in Science. Philadelphia, PA: Open University Press.

Falk, David, Dieter Brill and David Stork. 1986. Seeing the Light: Optics in Nature, Photography, Color, Visions, Holography. New York: Harper and Row.

Goldberg, Fred 1986. Student Difficulties in Understanding Image Formation by a Plane Mirror. The Physics Teacher 24: 472-480.

Osborne, Jonathan, P. Black, M. Smith and J. Meadows. 1991. LIGHT. Primary Space Project Research Report, Liverpool University Press.

Shapiro, Bonnie L. 1994. What Children Bring to Light. New York: Teachers College Press.

Ramadas, J. and R. Driver. 1989. Aspects of Secondary Students' Ideas About Light. Children's Learning in Science Project: CSSME, University of Leeds.

C. Bibliography on Light and Vision

Andersson, B. and C. Karqvist. 1983. How Swedish pupils, aged 12-15 years, understand light and its properties. European Journal of Science Education 5(4): 387-402.

Anderson, C.W. and E.L. Smith. 1983. Children's conceptions of light and color: understanding the concept of unseen rays. Paper presented at the annual meeting of the American Educational Research Association.

Asoka, H. 1993. First steps in the construction of a theoretical model of light: A case study from a primary classroom. In Proceedings of the Third International Seminar: Misconceptions and Educational Strategies in Science and Mathematics, J. Novak, ed. Ithaca, NY: Cornell University.

Brickhouse, N. 1994. Children's Observations, Ideas, and the Development of Classroom Theories of Light. Journal of Research in Science Teaching 31(6): 639-656.

Feher, E. and K. Rice. 1987. A comparison of teacher-student conceptions in optics. In Proceedings of the Second International Seminar on Misconceptions and Educational Strategies in Science and Mathematics, J. Novak, ed. Ithaca, NY: Cornell University.

Guesne, E. 1985. Light. In Children's Ideas in Science, R. Driver, E. Guesne and A. Tiberghien, eds. Philadelphia: Open University Press.

Sadler, P. 1991. Projecting Spectra for Classroom Investigations. The Physics Teacher 29(7): 423-427.

Shapiro, B.L. 1989. What children bring to light: giving high status to learners' views and actions in science. Science Education 73(6): 711-733.

Stead, B.F. and R.J. Osborne. 1980. Exploring science students' concepts of light. Australian Science Teacher's Journal 26(3): 84-90.

Watts, D.M. 1985. Students' conceptions of light-a case study. Physics Education 20: 183-187.


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