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Physics 3xxxW: Physics for Future Elementary School Teachers

Cycle 6, Activity 2: Children’s ideas about light and vision

Key question: What types of ideas do elementary school students have about light, and how might evidence impact children’s thinking?

Activity Purpose: In this activity, you will analyze two different videos involving 3rd and 4th grade students’ ideas about vision and reflection. The purpose of this activity is for you to get a sense of the types of pre-instructional ideas children have involving how we see things, and to think about how these ideas might evolve through classroom experimentation.

Initial Ideas (before viewing videos)

1. To begin a unit on light with her 3rd grade students, Ms. Jackson shows students a flashlight and asks them to draw pictures representing how they are able to see light. What initial ideas about how we see light do you think the 3rd grade students might express?

2. Early in Cycle 6 you conducted an experiment involving a mylar square and white paper sitting on the center of the table. You were asked to predict what each person standing around the table would see when the lights were turned off and a flashlight directed at the center of the table was turned on.

Imagine that 4th grade students conducted a similar experiment with only a mirror (not the white paper) in the center of the table. Imagine that they were asked to predict which of the four students standing around the table would see the light. What type of predictions do you think these students would make? Why do you think so?


Chuck--I really like this assignment. Do students answer these questions in class or outside of class? Do you collect their responses? Will they have an opportunity to discuss their responses in groups before viewing the video? Do you ask them to reflect, in writing, on whether their predictions were accurate?

This seems like a really insightful pedagogical tool. I could see these short responses being extended into an essay about student preconceptions and how these preconceptions may interfere with learning and how such preconceptions interact with actual experience. There is a video on this subject looking at the ideas students have about why summer is warmer than winter and how these preformed ideas interfere with their understanding of how the earth orbits the sun.

Gina: Thanks for your comments and suggestions.

The students answer the questions in class. They then discuss them with other members of their lab group (a group is 3 or 4 people), and sometimes come to a consensus. We then randomly pick several lab groups to briefly discuss their responses with the entire class. Usually others in the class will voluntarily contribute to the discussion.

After viewing the videos, they are asked another set of questions, with the same response arrangement. They are to provide evidence from the transcripts of the video and, in some cases, from still-shots of diagrams the students in the video have drawn.

In longer writing exercises our students have the opportunity to select some of their misconceptions and reflect upon how those misconceptions evolved into correct understanding and compare with "scientists' ideas."

In another writing exercise they discover other personal misconceptions by taking a true/false quiz from which they choose several of their incorrect answers and write a research paper correcting these and analyzing their misconceptions. One of these misconceptions is about why summer is warmer, etc. However, I don't know the video that you mention. I will try to track it down, but if you have ready information that you could provide me, it would be much appreciated. (It is possible that our astronomers have it in their film library and I've just not noticed it.)

Btw, we are always trying to come up with different, less loaded terms than "misconception." We most commonly use "preconception." The term you used, "preformed ideas," is not one that I have used, but I will in the future.

One of the course objectives is to make the students aware that we all have preconceptions with which we successfully negotiate the world. (Some of our misconceptions are operationally more useful than the underlying scientific laws.) If one understands these preconceptions, and the probable preconceptions of their future students, then taking them apart (deconstructing?) to find the buried scientific "truth" can be a valuable teaching strategy. It is most successful when the students are guided to personal discovery. But we constantly remind them that it took about two millenia to get from Aristotle to Galileo and Newton. One of the challenges is to guide our students to discover accepted scientific principles over the course of 15 weeks.

Chuck--interesting and rich assignments in which preconceptions, or presumptions, are triggered and interrogated. (As a non-scientist, I have NO idea which of the students standing around the table would see the light in the mirror!)

From a writing-pedagogy standpoint, I'm interested in how you can get the most out the quick-writes. I like the analysis involved in the longer writing exercises, and think that one of the most valuable things you can do in the shorter ones is to really insist that students commit their hypotheses and their rationales to writing. If these initial ideas are not written down, students might not really get a chance to stare them in the eye and figure out how it is that they came to think that way.


Thanks for the comments. You are right on the money. The students have a workbook which one might call a guided journal. Situations are posed in writing, and the students are asked to predict what will happen and explain why they make that prediction. The prediction may or may not be right, and similarly with the rationale, depending on how far along they are in the curriculum. They then do the experiment or a computer simulation. They then describe, in writing, the results of the experiment/simulation, and explain why in terms of their previous experiences and the theories that they are developing step by step. We have eight cycles of this nature, with five to ten experiments or simulations in each cycle. At the end of each cycle they are posed some "every-day" situations (the one today was brake-fade) which they are to explain, in writing, in terms of the principles they have developed. In each cycle there are four or five points at which the students report to the class, in turn, on their results, and the other class members compare to their conclusions in a discussion period. At the end of each cycle, the students are given a list of "scientists' ideas" which are in fact the laws of (classical) physics, including mechanics, gravity, magnetism, electricity, optics, and energy conservation.

They do some of this hypothesizing and analysis out of class as homework assignments, an average of twice a week, which are graded for content (wrong predictions are okay until we get to the end) and writing. We spot check the in-class writing for completeness and clarity.