Private Universe Project in Science

Workshop Six: "Where Should We Start?"

Section 1 - About Workshop Five:
"Where Should We Start?"

What is the theme of this workshop?
The theme of Workshop Six is "choosing a goal for conceptual learning."

Whom do we see in the video?
Robert, a new teacher, discovers that sixth graders create models to predict the motions of objects. With this information as a foundation, how should Robert proceed with his lesson plan for next term?

What happens in the video?
The concepts of friction and energy dissipation are inventions of science. If the teacher tells the students to "ignore friction," will the students know what that means? If Robert presents a new problem in a different context, will his students accept and correctly apply the scientists' counter-intuitive definition of friction?

What problem does this workshop address?
We all live in a world dominated by friction. When we ice-skate or slip on a banana peel, friction is reduced for a time, but it is never entirely removed. Students, however, are asked to "imagine a world without friction" when studying force and motion. Faced with the conflict between the world of everyday experience and the frictionless world they are asked to imagine, how are children to make sense of the lesson?

What teaching strategy does this workshop offer?
This workshop examines how students and teachers can work within a scientific view. The particular challenge is developing lessons that serve as bridges from the learner's experience to the scientist's view. In order to achieve this link, the teacher must first set content goals and elicit student ideas to make clear the gap between the learner's experience and the science idea. The lesson then becomes a platform across which the student can move from understanding ideas in an "everyday" context to understanding them in a "science" context. This strategy is called bridging and often employs analogies.

Section 2 ­ "Where Should We Start?"

A. The Goals for Workshop Six

"Where Should We Start?" is for teachers interested in new ways of creating lesson plans, selecting appropriate educational strategies, and addressing student assessment.

The goal of this workshop is to reach such teachers.

Workshop Discussion

How can teachers create lessons that start from the students' ideas?

B. Challenges

The newest educational strategies are necessarily first implemented under special conditions. Therefore, in portraying a specific instructional approach, these strategies may not seem to apply to everyday classroom experiences.

Workshop Discussion

Can lessons learned in a "lab-school" setting be relevant in more typical classrooms? (A lab-school setting refers to classrooms established in designated schools for the purpose of testing and evaluating new teaching approaches.)

 

 

 

Section 3 - Exercises

A. Exercise: Responding to Workshop Six

One of the important scientific ideas explored in this workshop is friction. The following exercise is for teachers, but can also be used in the classroom as a student exercise to explore the concept of friction.

Workshop Activity

Write a series of fictional diary entries in which you are suddenly transported to a world without friction.

• How is this world different from ours?
• What are some of the first things you notice in this new world?
• In what way is life improved in a world without friction?
• In what way is it made worse?
• What sorts of inventions and/or machines are made possible or impossible in a world without friction?

B. Exercise: Preparing for Workshop Seven

You will get the greatest benefit from the next workshop if you complete the following exercise. Ask students, colleagues, friends, and yourself the following question.

Pre-Workshop Activity

Leaves fall off trees and eventually turn to dirt. Is the Earth getting bigger and bigger as the dirt from the leaves accumulates? Why or why not?

 

Section 4 - Educational Strategy

A. Anchoring Examples and Bridging Analogies

Another example of "bridging analogies" as a teaching strategy can be found in the materials for Workshop Five: "Can We Believe Our Own Eyes?" This strategy may be effective when the 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 bodies in motion. This example will also help develop students' skills in graphing and extrapolating from data.

In this approach we take a cue from Galileo. The target concept that we want the students to understand is contained in Newton's first law of motion. (See Section 3, Part B: "Historical Ideas" for discussions of Galileo and Newton.) The anchoring example is a phenomenon that, according to the research, most children believe. This phenomenon is embodied in the fact that a ball rolled on a surface of high friction will quickly come to a stop. The bridge to the target concept is built by rolling the same ball with the same initial force on surfaces of less and less friction. As the students graph the results, they may come to see that the ball could roll on "forever" if all friction could be removed. Even though we can never completely remove friction from the exercise, we can help make Newton's law more plausible for many of the students.

Materials for Experiment

1. Marbles or small balls of uniform size and weight.
2. Surfaces of various degrees of friction. These surfaces could include lengths of deep pile carpet, medium pile carpet, flat indoor-outdoor carpet, rough wood, polished wood, tile, etc. If performed outdoors, surfaces could also include deep sand, loose dirt, tall grass, freshly-mowed grass, and concrete. In all cases, care must be taken to determine that the surface is level.
3. A "starter." The starter device must be able to start the ball rolling with about or nearly the same force each time. The spring-loaded plunger from an old pinball machine would be more than adequate. (This device propels the steel ball into the body of the pinball machine at the start of each game.) The teacher and students could also try to invent a good starter from rubber bands, based on the principle of a sling-shot. In this case the model should not be a very strong sling-shot. In the absence of a mechanical device, a student or the teacher could start the ball each time with a flick of a finger, attempting to duplicate the force on the marble with each start. This last method, however, raises the conscious or unconscious suspicion of bias or "cheating" on the part of the starter.

Method

Predict: Before rolling the marbles or balls over the various surfaces, the teacher asks the students to predict what will happen. Do they expect the balls to roll farther over some surfaces, less over others? Which surfaces will permit longer "trips" by the balls and why?

Measure and Record: During the exercise the "starter" is used to propel the marble or ball over each of the surfaces. Students should carefully measure and record the length traveled by the ball in each trial. For further accuracy, several tries can be made over each surface and the results averaged.

Graph Data: After all of the measurements are recorded, students can work alone, in small groups, or as a class to graph these data. A graph can be created with the lengths traveled on one axis plotted against the various surfaces on the other axis. Arrange the graph so that the data on it progress monotonically from the shortest trip to the longest one. Ask the students how well the data fit their predictions. Ask them to explain the pattern they see in their graphs.

Discuss: By drawing a curve through the data points, students can infer that the ball rolls farther across surfaces that offer less "resistance." This resistance is called "friction." By extending the curve, you can help the students extrapolate to the behavior of a ball rolling across an ideal frictionless surface. As with any strategy, this activity will leave some children unconvinced. Some students, however, may come to accept that in a frictionless situation, the ball would roll "forever" without stopping-if the surface were long enough.

Section 5 - Resources for Workshop Six

Disclaimer

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 its presence in this guide. Descriptions of such entities are for reference purposes only. We have provided this information to help you to locate materials and information.

A. Related Resources

Interactive Physics II-a computer program. For information contact:

Knowledge Revolution

15 Brush Street

San Francisco, CA

1-800-766-6615

Fax: 1-415-553-8012

Ardley, Neil. 1992. The Science Book of Energy. San Diego: Harcourt Brace Jovanovich, Publishers. To order:

Harcourt Brace and Company

525 B Street, Suite 1900,

San Diego, CA 92101

619-699-6208

Fax: 619-699-6220

Marson, Ron. 1990. Motion. Canoby, OR: TOPS Learning Systems.

TOPS Learning Systems

10970 South Mulino Road

Canby, OR 97013

503-263-2040

B. Further Reading

Goldstein, M. and I. Goldstein. 1993. The Refrigerator and the Universe/Understanding the Laws of Energy. Cambridge, MA: Harvard Press.

Gonick, L. and A. Huffman. 1990. The Cartoon Guide to Physics. New York: Harper Perennial.

Krauss, L. M. 1993. Fear of Physics/A Guide for the Perplexed. New York: Basic Books.

Hollander, J., ed. The Energy-Environment Connection. Washington DC: Island Press.

Ronan, C. A., ed. 1993. Science Explained/The World of Science in Everyday Life. New York: Henry Holt and Company.

C. Bibliography on Energy

Bliss, J. and J. Ogborn. 1985. Children's choices of uses of energy. European Journal of Science Education 7: 195-203.

Brook, A. 1987. Designing experiences to take account of the development of children's ideas: An example from the teaching and learning of energy. In Proceedings of the Second International Seminar on Misconceptions and Educational Strategies in Science and Mathematics (Vol. III, pp. 84-97), J.D. Novak, ed. Ithaca, NY: Department of Education, Cornell University.

Brook, A. and R. Driver. 1986. The construction of meaning and conceptual change in classroom settings: Case studies of energy. Leeds: UK University of Leeds.

Carr, M., V. Kirkwood., B. Newman and R. Birdwhistel. 1987. Energy in three New Zealand secondary school junior science classrooms. Research in Science Education 17: 117-128.

Duit, R. 1981. Understanding energy as a conserved quantity. European Journal of Science Education 3(3): 291-301.

Erickson, G. and A. Tiberghien. 1985. Heat and temperature. In Children's Ideas in Science, R. Driver, E. Guesne and A. Tiberghien. Philadelphia: Open University Press.

Gunstone, R. and M. Watts. 1985. Force and motion. In Children's Ideas in Science, R. Driver, E. Guesne and A. Tiberghien. Philadelphia: Open University Press.

Solomon, J. 1982. How children learn about energy or does the first law come first? School Science Review 63: 415-442.

Solomon, J. 1983. Learning about energy: How pupils think in two domains. European Journal of Science Education 5: 49-59.

Solomon, J. 1992. Getting to know about energy-in school and society. London: The Falmer Press.

Warren, J. 1986. At what stage should energy be taught? Physics Education 21: 154-155.

Watts, M. 1983a. A study of school children's alternative frameworks of the concept of force. European Journal of Science Education 5: 217-230.

Watts, M. 1983b. Some alternative views on energy. Physics Education 18:213-216.

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