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How Students Learn: Science in the Classroom (2005)

Chapter: 10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level

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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 78
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
Page 80
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 81
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
Page 82
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 83
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 84
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 90
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 91
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 92
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 93
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 94
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
Page 95
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Page 96
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
Page 100
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
Page 101
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
Page 103
Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
×
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Suggested Citation:"10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level." National Research Council. 2005. How Students Learn: Science in the Classroom. Washington, DC: The National Academies Press. doi: 10.17226/11102.
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421 10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level Shirley J. Magnusson and Annemarie Sullivan Palincsar Children at play outside or with unfamiliar materials look as though they might be answering such questions as: What does this do? How does this work? What does this feel like? What can I do with it? Why did that happen? This natural curiosity and exploration of the world around them have led some people to refer to children as "natural" scientists. Certainly these are the very types of questions that scientists pursue. Yet children are not scien- tists. Curiosity about how the world works makes engaging children in sci- ence relatively easy, and their proclivity to observe and reason (see Chapter 1, Box 1-1) is a powerful tool that children bring to the science classroom. But there is a great deal of difference between the casual observation and reasoning children engage in and the more disciplined efforts of scientists. How do we help students develop scientific ideas and ways of know- ing?' Introducing children to the culture of science its types of reasoning, tools of observation and measurement, and standards of evidence, as well as the values and beliefs underlying the production of scientific knowledge—is a major instructional challenge. Yet our work and that of others suggest that children are able to take on these learning challenges successfully even in the earliest elementary grades.2

422 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM mE STUDY OF AGE Unlike madhematics, in which topics such as whole-number arithmetic are foundational for The study of rational nurnber, and bodh are foundational for The study of functions, There is currendy little agreement on The selection and sequencing of specific topics in science, particularly at the elementary levels What clearly is foundational for later science study, however, is learn- ing what it means to engage in scientific inquiry—learning The difference between casual and scientific investigations. That learning can be accom- plished in The context of many different specific topics. In dais chapter, we choose light as our topic of focus because it affords several benefits. The first is practical: The topic involves relatively simple concepts that children can undo stand from investigating widh relatively simple matenals. For example, our bodies and The sun make shadows dhat can be studied, and similar studies can occur with common flashlights and class- room materials Pencil and paper, and perhaps some means of measuring distance, are all that is needed for data collection. Children can also study light using simple light boxes (Elementary Science Study's Optics unit ) in which light bulbs are placed in cardboard boxes containing openings cov- ered widh construction paper masks that control The amount of light emanat- ing from The box. Thin slits in The masks make the dlin beams of light necessary for studies of redection and refraction. Multiple wider openings covered widh different colored cellophane filters enable investigations mix- ing colors of light. And again, pencil and paper are all that are needed for data collection showing The padhs of light. In addition, developing scientific knowledge of light challenges us to conceptualize aspects of The world that we do not directly experience—a critical element of much scientific study. For example, light travels, yet we do not see it do so; we infer its travel when we turn on a flashlight in The dark and see a lighted spot across the room, t)eveloping scientific knowledge often requires conceptual changes in which we come to view The physical world in new ways 6 Students must learn dhat things are not always what They seem—itself a major conceptual leap. The study of light gives children an accessible opportunity to see The world differently and to challenge their existing conceptions. We see the world around us because light redects from objects to our eyes, and yet we do not sense dhat what we see is The result of reflected light. Some children, moreover, view shadows as objects instead of under- standing dhat shadows are created when light is blocked. Conceptual devel- opment is required if they are to understand The relationship among a light source, an ob ect, and The shadow cast by that object. Working widh dash- lights can provide children an opportunity to challenge directly everyday conceptions about shadows, providing them with a powerful early expen-

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 423 ence of scientific ways of knowing. Because casual observation of The be- havior of light can be misleading, but a relatively accessible investigation of light can be illuminating, the study of light demonstrates the contrast between casual observation and expenmentation. For all these reasons, Then, The study of light supports children's understanding dhat relationships in The physical world are not self-evident and that constructing scientific knowledge from observation of The world is different from their everyday reason ng. Three major instructional challenges parallel The principles of How People Learn as They apply to The study of light: (1) providing students widh oppor- tunities to develop deep conceptual understanding of targeted aspects of light, and of standards and norms in science for investigating and drawing conclusions (bodh about light and more generally); (2) supporting students in building or bridging from prior knowledge and experience to scientific concepts; and (3) encouraging children to engage in the kind of metacognitive questioning of Their own thinking dhat is requisite to scientific practice. Conceptual Understanding How People Learn suggests that learning for understanding requires the organization of knowledge around core concepts. Thus while light can be studied with tools dhat are easy to use and opportunities to observe the behavior of light abound, if The classroom activity described in This chapter were simply a set of experiences and observations, it would leave students widh little deep knowledge Experiencing many individual activities (e.g., seeing dhat light reflects from wood as well as mirrors) does not ensure dhat students understand The overarching concepts about light outlined below that allow Them to predict how light will behave in a wide variety of circum- stances. As a result, a major focus in This chapter is on The role of The teacher in guiding students' observations, reasoning, and understanding so dhat core concepts are grasped. What conceptual understandings do we consider to be core? As sug- gested above, grasping the differences between everyday observations and reasoning and those of science is not only core in our approach to teaching about light, but also paramount in providing a foundation for further science study. Salient concepts include The following: . Standards of The scientific community for understanding and commu- nicating ideas and explanations about how The world works are different from everyday standards. Science requires careful observations dhat are re- corded accurately and precisely, and organized so dhat patterns can be ob- served in the data. · Patterns in observations are stated as knowledge claims.

424 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM · Claims are judged on the quality of the evidence supporting or disconf~rming them. · Hypotheses take on the status of claims only after they have been tested. · Claims are subject to challenge and not considered new sciellTiflc knowledge until the scientific community accepts them. These understandings are foundational for all future study of science. There are also core concepts regarding the topic of light that we want students to master. These will vary somewhat, however, according to the grade level and the amount of time that will be devoted to the topic. These concepts include the following: . All objects (expenenced in our everyday lives) reflea and absorb light, and some objects also transmit light. - Dark or black objects mainly absorb light; light or white objects mainly reflect light. - There is an inverse relationship between light reflected Tom and absorbed by an object: more reflected light means less absorbed light. · Light reflects from objects in a particular way: the angle of incoming light equals the angle of reflected light. · What we see is light reflected from objects. - There must be a source of light for us to see an object. - Sources of illumination can produce light (e.g., the sun) or reflect light (e.g., the moon). · When an object blocks a source of light, a shadow is formed. Shad- ows are dark because there is no light reaching them to be reflected to our eyes. The distance of an object from a source of light it blocks detemmines the size of the object's shadow. The shape of an object's shadow depends on the angle of the object to the light, so the shadow of an object may have more than one shape. . The color of an object is the color of light reflected from the object. - The colors of light come from white light, which can be separated into many colors. - The color of an object depends on the extent to which particular colors of light in white light are reflected and absorbed. Other concepts such as the nature of light as both a wave and a par- ticle—are beyond what elementary students need to understand. But teach- ers need to know these core concepts to deal effectively with questions that may arise, as we discuss later in this chapter

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 425 Prior Knowledge Students bring many prior conceptions about light to The classroom. Some of These are influenced relatively easily. For example, some students believe a shadow is an object, but This conception is not deeply held, and simple experiments with light can provide convincing evidence to The con- trary. Other scientifically inaccurate conceptions are not so easily changed by simple expenments. A very common belief is dhat light reflects only from shiny objects, such as a mirror or shiny metals. This is hardly surpnsing; reflections from shiny objects are strikingly obvious, while observing reflection from objects widh no apparent shine requires a tool (e.g., a simple device such as a piece of paper strategically placed to show redected light, or a more sophisticated device such as an electronic meter dhat measures light energy). In fact, The nature of light has puzzled scientists for centunes.7 Part of The challenge to our understanding is that the behaviors and effects of light are not easily determined by our senses. Light travels too fast for us to see it traveling, and our observation of light that has traveled great distances, such as light fi om The sun and odher stars, provides no direct evidence of The time it has taken to reach us. Scientists have determined dhat light exerts pressure, but this is not something we can feel. We see because light is reflected to our eyes, but we have no way of experiencing dhat dilectly. We commonly Think of color as an intrinsic characteristic of an object because we do not experience what actually occurs: dhat The color we see is the color of light reflected from the object. Furthermore, grasping This notion requires understanding that white light is made up of colors of light Slat are differentially absorbed and re- flected by objects. If none are reflected, we see black, and if all are reflected, we see white, and This is counter to our experience with colored pigments that make a dark color when mixed togedher Finally, perhaps The strongest testimony to The complex nature of light is The fact that scientists use two very different models to characterize light: a particle and a wave. Because daily experience reinforces ideas that may be quite different from scientific understanding, fostering conceptual change requires supporting students in paying close attention to how they reason from what They ob- serve. For this reason, The approach to teaching we suggest in this chapter provides students with a great many opportunities to make and test knowl- edge claims, and to examine The adequacy of Their own and adhere reason- ing in doing so. Once again, however, The role of the teacher is critical. As we will see, The prior conceptions widh which students work may lead Them to simply not notice, quickly dismiss, or not believe what They do not expect to see.

426 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM Recognition Young children, and indeed many adults, assume that things are as they appear, and no further questioning is required. That light redects off objects only if they are shiny may appear to be true and in no need of further questioning. Science, however, is about questioning—even when somedhing seems obvious because explanation is at the heart of scientific activity. Thus The search for an explanation for why shiny objects redect light must include an answer to The question of why nonshiny objects do not. Such a search, of course, would lead to evidence refuting The notion that only shiny objects redect light Engaging children in science, Then, means engaging Them in a whole new approach to questioning. Indeed, it means asking Them to question in ways most of us do not in daily life. It means question- ing The typical assurance we feel from evidence dhat confirms our prior beliefs, and asking in what ways The evidence is incomplete and may be countered by additional evidence. To develop thinking in this way is a major instructional challenge for science teaching. THE STUDY OF LIGHT THROUGH INQUIRY Widh the above principles in mind, we turn now to The learning of science Through investigative activity in The classroom, or inquiry-based in- struction.8 Investigations in which students directly observe phenomena, we believe, serve several critical functions. First, when students experiment with light and observe phenomena they do not expect, These discrepant experi- ences can directly challenge Their inaccurate or partially developed concep- tions. Students will need many opportunities to observe and discuss The behavior of light that behaves in unexpected ways if They are to develop scientific conceptions of light. Inquiry dhat is designed to occur over weeks and allows students to work widh many different materials can provide dhat experience. The opportunity for repeated cycles of investigation allows stu- dents to ask the same questions in new contexts and new questions in increasingly understood contexts as they work to bring Their understanding of The world in line widh what scientists Think Equally important, participa- tion in well-designed guided-inquiry instruction provides students with a first-hand experience of the nomms of conducting scientific investigation. But inquiry is a time- and resource-intensive activity, and student inves- tigations do not always lead to observations and experiences That support The targeted knowledge. Therefore, we combine first-hand investigations with second-hand investigations in which students work with The notebook of a fictitious scientist to see where her inquiry, supported by more sophis- ticated tools, led. This second-hand inquiry provides a common investiga- tive experience that allows The teacher to direct attention to steps in The

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 427 reasoning process pursued by the scientist that led to the development of core concepts. Moreover, it allows students to see that while scientists en- gage in a similar type of inquiry, more sophisticated tools, more control over conditions, and larger sample sizes are critical to drawing conclusions that can be generalized with some confidence. A Heuristic for Teaching and Learning Science Through Guided Inquiry To aid our discussion of the unfolding of instruction, we present a heu- nstic—a thinking tool—to support planning, enacting, and evaluating guided- inquiry instruction with elementary school teachers.9 This heuristic (see Fig- ure 10-1'°), which shares many features with other researched-based approaches to teaching elementary science through investigation," repre- sents instruction in terms of cycles with phases. The words in all capital letters in Figure 10-1 indicate the phases, and the lines with arrows show the progression from one phase to the next. Reposing is a key phase in this conception of instruction; it is the occasion when groups of students report the results of their investigations to their classmates. Students are expected to report on knowledge claims they feel cone dent in making and providing evidence for those claims from the data they collected during investigation, This expectation lends accountability to students' investigative activity that is often absent when they are simply expected to observe phenomena, To make a claim, students will need precise and accurate data, and to have a _;~ / m/atipmship / / axptanatipms 9! ~ Iheor es) ENGAGE PREPARE to q~estbn I NV ANTI GATE m thodi~J ted mmbr~ t 9 Magnussttn ZOO 1 REPORTING CisssnKtm + Small Getup Community Public Shanng ~ Fvdudlon \ Maims and \e thence thmntes, \ Pn~ddipms, \ osmium ms I PREPARE to REPORT _ INVESTIGATE ~ obmwv ton mad Em mmmtbton FIGURE 1 0 1 A cycle of inveshgahon in guided inqui y science t

428 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM claim that is meaningful to the class, they will need to understand the rela- tionship between the question that prompted investigation and the way in which their investigation has enabled them to come up with an answer Multiple lines leading from one phase to another indicate the two basic emphases of investigative activity in science: generating knowledge that describes how the world works (outer loop), and generating and testing theories to explain those relationships (inner loop). The reporting phase always marks the end of a cycle of inquiry, at which point a decision is made about whether to engage in another cycle with the same question and inves- tigative context, or to re-engage with a novel investigative context or a new question. Cycles focused on developing knowledge claims about empirical relationships generally precede cycles in the same topic area focused on developing explanations for those relationships. Thinking and discussing explanations may occur in other cycles, but the focus of the cycle repre- sented by the inner loop is on testing explanations. Each phase in the heuristic presents different learning opportunities and teaching challenges Each also provides opportunities to focus on ideas de- scnbing the physical world (concepts and theories or content) as well as the means by which we systematically explore the nature of the physical world (methods and reasoning or process). Each phase requires different types of thinking and activity on the part of the students and the teacher; hence, each has a unique role to play in supporting the development of scientific knowledge and ways of knowing, The following illustrations of teacher and student activity in each phase of instruction are drawn from our work in elementary school classrooms.' The Engage Phase Descriptions Each unit of study begins with an engagement phase, which onents thinking and learning in a particular direction. In the elementary classroom, a version of the classic KWL (i.e., what do I Know, what do I Want to learn, what have I Learned) can be a fine way to initiate engage- ment. In contrast to the typical use of KWL in the language arts, however, to maximize the value of having students identify what they know, teachers should invite students to identify how they have come to know the topic area doing so can develop students' awareness that "knowing" can mean different things Does their knowledge anse from something they actually observed? If so, where and when did that occur, and under what circum- stances? Or did others observe it and report it to them? If so, how confident were they in what was reported and why? If a student reports knowledge from something written in a book, what other information was provided? Were any data provided to substantiate the claim ? How extensive was the information provided regarding what the student reports knowing? This dis-

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 429 cussion can provide the grist for later camper sons of ways of knowing in everyday life versus in science, history, or the language arts. It also affords teachers an opportunity to draw out and learn about students' prior knowl- edge, metacognitive awareness, and reasoning abilities. For example, in a class beginning to investigate how light interacts with matter, one student stated that he already knew the answer because he knew that objects were opaque, transparent, or translucent. This statement indicated to the teacher that the student might assume light interacts with an object in only one way, which could limit what he observed. Knowing of this possibility, the teacher would want to monitor for it, and possibly raise questions about the thor- oughness of students' observations. The scientific community defines for itself what knowing in particular ways means. For example, in each discipline (e.g., physics, chemistry, biol- ogy), the community defines what are acceptable methods for data collec- tion and what constitutes precise and accurate observation. The community also dictates what constitutes a valuable contribution to the knowledge base. The relative value of a contribution is a function of the extent to which it extends, refines, or challenges particular theories of how the world works. In our everyday world, we do not have a community detemmining the valid- ity of our thinking or expenences. Thus, the initial conversation when be- ginning a new area of study provides an important opportunity for the teacher to ascertain children's awareness of the roots of their knowledge, as well as the expectations of the scientific community. For example, when students describe knowing something about the physical world but indicate that their knowledge did not arise from observation or direct expenence, the teacher might ask them to think about what they have observed that might be the kind of evidence scientists would expect to have. When students do provide evidence, the teacher might ask them questions about that evidence such as those above, reflecting the norm that systematic study under controlled con- ditions is a hallmark of the practice of science, and that evidence not ob- tained under those conditions would lead scientific thinkers to be skeptical about the knowledge claim. The next step in engagement is to begin to focus the conversation about the topic of study in ways that are likely to support the learning goals. For example, showing students the kinds of materials and equipment available for investigating can lead to a productive conversation about phenomena they can explore. Focusing on ideas that were generated during the KWL activity, the children can be encouraged to suggest ways they might investi- gate to determine whether those ideas are scientifically accurate (meaning that the claims can be backed by evidence from investigation). Students can also be encouraged to identify what cannot easily be studied within the classroom (because of the nature of the phenomenon or a lack of resources or time) and might be better studied in a second-hand way (i.e., through

430 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM reading or hearing about what others have studied and concluded from first- hand investigation). For example, we observed a group of third graders studying light who had numerous questions about black holes, the speed of light, and light sources on different planets, all of which they decided were best pursued through second-hand investigation At the end of engagement, the students should have a sense of a general question they are trying to answer (e.g., How does light interact with mat- ter7), and should have identified a particular question or questions to be the focus of the first cycle of investigation. To this end, a teacher might (1) focus the class on a particular phenomenon to study and have them suggest spe- cific questions, (2) draw upon conflicting ideas that were identified in the KWL activity and have the class frame a question for study that can infomm the conflict, or (3) draw on a question that was identified during the discus- sion that is a profitable beginning for investigation, ilustratiOrL What does this kind of beginning look like in a classroom? In a kindergarten classroom,'3 after a brief opportunity for the children to state what they thought they knew about light and how it behaved, the teacher, Ms. Kingsley, ar anged for pairs of students to take turns using flashlights in an area of the classroom that had been darkened. This activity provided children an opportunity to become familiar with investigative materials and phenomena that Ms. Kingsley knew would be the focus of later investiga- tion. The children responded to this activity in a variety of ways, from ini- tially becoming focused on finding spiders to dwelling later on the effects they could create with flashlights. For example, one student commented on the colors she saw as she shone the flashlight on the wall in the darkened area: "There's color When it shines on a color, then it's the color, green, or white, or red, or black. And then you put the light on the ceiling, it's gone." In the following interaction, the children "discover" reflection: IAnisha walks forward under the loft, holding the flashlight with her left hand at an angle to the mi rror that she holds flat in front of her I Oh Deanna, look, I can bounce the light. [Deanna holds the mirror so light is bouncing directly behind her I Deanna Excitedly If you look back, maybe you can see the light. A third student focused on what he saw while holding ob ects in the beam of light. The following interchange occurred when the students explored with large cardboard cutouts of letters of the alphabet.

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 431 Jeremy Hazel Working with a letterl Ooo. this makes a shadow. A different shadow Ithan the one he just sawl. IHe picks up the letter G and hands it to his partner I See if the G makes a shadow. It does make a shadow. See, look at th is. When the children described their observations to the class, Ms. Kingsley was able to use those observations to elicit the children's current ideas about light and shadows and how they might investigate those ideas. In a fourth-grade classroom,'4 the teacher, Ms. Lacey, introduced her students to the study of light by asking them what they wondered about light. The children identified over 100 "wondenngs," including questions about how we see, why we see rainbows of color from some glass objects or jewelry, what makes light from the plastic sticks you bend to make them "glow" in the dark, what are black holes, and how fast is the speed of light. The next day, students were given a written assessment about light, pre- sented as an opportunity for them to identify their current thinking about the nature and behavior of light. After reviewing students' responses, Ms. Lacey wrote statements on the board (see Table 10-1) indicating the vanety of ideas the class held about light. The variation in views of light exhibited by the students provided a reason to investigate to determine the accuracy of the ideas and the relationships among them. TABLE 10-1 Fourth Graders' Initial Ideas About Light Light travels. Light travels in a curved path. Light travels in a straight line. Light travels in all directions. Light can be blocked by materials. Light can shine through materials. Light can go into materials. Light can bounce off of materials. Later in the unit on light, Ms. Lacey turned to other wonderings the students had about color and light. In the following excerpt, she ascertains whether students' questions came from what they had been told, read, or observed, and she prompted one student to hypothesize about color from what had previously been learned about the behavior of light. Ms. Lacey I know you guys had a few questions about color, so I'm wondering what you know or would like to know about colors What is it you think you want to learnt Levon7 When I said that my shirt's a light blue, you said how do we know its And you said we might be able to tell. Levon

432 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM Levon Ms. Lacev Tommy Ms. Lacey Tommy Ms. Lacey Ja red Ms. Lacey Ja red Ms. Lacey Ma rcus Ms. Lacey Ma rcus Ms. Lacey Ma rcus Ms. Lacey Ma rcus Ms. Lacey Michael Ms. Lacey Ma rcus Michael Ms. Lacey M m - h m m. You want to know how you know it's blue7 And you said we might be able to tell how. Well, I think you want to knowwhy when you see a blue shirt, you—it's blue. Okay. We might be able to figure that out. Tom7 What is it you want to know7 How you change color with light. I know it's real, cause I seen it. What did you see 7 Light makes your shirt be a different color I want to know how to do that. Hmm. Jared7 I'm wondering how light can make color How light can make color7 You think it does7 Yeah. Oh. Marcus7 I think light is color You think light is color Hmm. So, is that a hypothesis or is that something you really think7 Hypothesis. It's something I heard. Okay. So we'll see if that's right or not. How does light blend, blend. How does it . . . Different colors of light blend. Like, in the first- hand, the white light blends with . . . Do you mean bend7 Okay. I don't really have a question about color, but I have a question about light. Why do they call light, light7 Ah! Good question. Cause it's, cause it's light, like a light color You can't even see it. And why did they call it that7 Why did they call it7 What do you think they should call it7 Something 'cause it's so light, you can't see it. How does color make whiten How does color make white7 it does7 Mm-hmm. Ms. Lacey Michael Ch ris Ms. Lacey Ch ris

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 433 Ms. Lacey You think so ~ Chris Yeah. I saw it in a book. Ms. Lacey So, that is your hypothesis. Ronny How does color interact with lights Jared How does light, how does light form colors Ms. Lacey How does light make colors You think it does7 Jared How does light form color and make colors Ms. Lacey Do you think there's a difference between the word form and makes Or do you think it's the same things Jared it's kinda the same. Forms like light, or some- thing. Ms. Lacey Do you think light forms color7 Jason Yeah. Ms. Lacey What makes you think that it might do that7 Jason Cause light does. Ms. Lacey You just think that7 That's a hypothesis you're thinking. Okay Andrew it's not a, I don't have a question, but it's sort of a thought. I read in this book that when colored light reflects off, like, the same color, that it'll reflect off that. Ms. Lacey I don't understand what you mean. Andrew Okay. If, if there's red light and it reflected off somebody's red shirt. . . Ms. Lacey Reflected like off like Jared's shirt7 Andrew Red, yeah, red shirt. Ms. Lacey Okay. Andrew And then, to another red shirt and off. Ms. Lacey So you think this red light can bounce only if it's on red stuffy is that what you're thinking7 Andrew Yeah. Or if it reflects on like green, red light can't reflect on a green object. Ms. Lacey Red light can't reflect on a green object7 What would happen to it if wouldn't reflect7 Andrew it'd stay in. it'll absorb. Ms. Lacey You think it might absorb7 Could it do anything else7 Andrew lpausel Transmit7 Ms. Lacey You think it might transmits Oh. Jamal7 We've got some good ideas here

434 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM A common strategy for engagement not illustrated here is The use of a discrepant event—a phenomenon whose behavior or result is unexpected. For example, if one shines a bright, Olin beam of light at an angle into a rectangular block of clear, colorless glass with a frosted surface, one can see Blat the light interacts with The block in multiple ways. Because The object is transparent, students are not surprised to see light through it, but They may be surprised that The light goes through at an angle (refraction), and They are surprised that light also reviews off the block where it enters and where the reframed light exits The block. We can Then ask The question: If light behaves in all These ways with This material, does it do The same with odher matenals? While it may be easy to engage children with unfamiliar phenomena or new aspects of familiar phenomena, it is more challenging to support them in developing scientific understanding of the world because scientists often "see" The world differently from what our senses tell us so using the en- gagement phase to gain knowledge about The conceptual resources students bring to instruction is just The first step. As The knowledge-building process unfolds in subsequent phases, paying attention to how students use Those ideas, promoting the use of particular ideas over odhers, and introducing new ideas are key. In the next phase, the primary focus shifts from eliciting students' thinking about what The physical world is like to preparing them to investigate it in scientific ways. The P~epa~e-t~lnvestigate Phase Description Preparing to investigate is an opportunity for teachers to sup- port children in learning how scientific knowledge is produced. While in- quiry often begins with a general question, investigation must be guided by very specific questions. Thus, an important goal of this phase of instruction is to establish The specific question That will be The subject of the subsequent investigation.'9 The question must be specific enough to guide investigation, amenable to investigation by children, and central to the unit of study so That students can construct The desired knowledge of scientific concepts, proce- dures, and ways of knowing. If The teacher presents a question, it is impor- tant that this be done in a way that involves the children in discussion about why The question is important and relevant to understanding The broader topic of inquiry. This discussion provides an opportunity to signal the role of questions in scientific investigation and prompts the metacognitive activity that is The hallmark of any good reasoning. If students suggest a question, or the teacher and students togedher generate The question, it is still important to check the students' understanding about how The question is relevant to the topic of study.'6 Once a question has been specified, attention can turn to determining how The question will be investigated. This is a critical issue for scientists,

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 435 and is no less important for children's developing understanding. The teacher may provide information about procedures to use, students may invent or design procedures, or the teacher and students may work together to deter- mine how investigation should be carried out. Increasingly, there is evi- dence that children can think meaningfully about issues of medhodology in investigation.'7 Nevertheless, it is always important for The teacher to check students' understandings about why particular approaches and procedures are useful to answering The question. To This end, The teacher might ask students to describe The advantage of using particular materials or tools over odhers, or to tell why particular steps or tools are necessary. Then, during The actual investigation, The teacher should periodically reassess students' un- derstanding of what dhey are doing to ascertain whether accurate under- standing was sustained in The face of their actual encounter with phenom- ena. In addition, The teacher can ask students to evaluate The effectiveness and accuracy of their tools or procedures. These actions support students' metacognitive awareness regarding The question-investigation relationship. We Think of investigation in classrooms as addressing how students should interact with matenals, as well as with one another (when investigation is carried out by groups of students). A critical aspect of preparing to investi- gate is determining with students what they will document and how during their investigation. This may take The form of discussing The extent to which procedures need to be documented (only to a small degree when students are all investigating in The same way, but in detail when groups of students investigate differently), and promoting and illustrating The use of drawings to show investigative setups. If The amount of data collection has been left undefined, the students will need to consider how dhey will know when they have collected enough data. The fact That students will have to make and report claims and evi- dence to their classmates lends greater significance to this issue. Students may find dhey need to collect more data to have sufficient amounts to convince their classmates of their claim in comparison widh what they might have found convincing. Finally, it will be important to have students dis- cuss how to document observations so dhey are accurate, precise, and informative. When students are working in groups, assigning Them roles can be help- ful in supporting them in working togedher effectively. There are various types of roles That students can adopt during investigation Possible roles to support effective management of the students' activity are Equipment Man- ager, Timekeeper,'8 and Recorder These roles are not unique to scientific inquiry, but o he- roles are. For example, having The required materiels does not mean That students will use Them effectively; it is necessary to monitor that The correct procedures are being carried out and with care. In addition, a number of responsibilities attend data collection, such as

436 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM ensuring that enough data will be collected to fulfill the norms of scientific investigation, determining the level of precision with which observations are to be made (e.g., whether length should be recorded to the centimeter, tenth of a centimeter, or hundredth of a centimeter).'9 These sorts of issues form the basis for intellectual roles that students can adopt, in contrast to the management roles discussed above 7 These roles, rather than being named for a task, are named for the conceptual focus maintained during investiga- tion. For example, one student in a group can assume pnrnarv responsibility for pressing the group to evaluate how well procedures are working and being camed out in order to answer the question. Another student can be given pnrnarv responsibility for evaluating the extent to which the data be- ing collected are relevant to the question. Finally, another student can be given pnrnarv responsibility for checking whether the group has enough data to make a claim in answer to the question. If the practice of adopting roles is utilized, the prepare-to-investigate phase is used to set this up. Modeling and role-playing are helpful to sup- port students in adopting roles that are new to them. In addition, the formal assignment of roles may change over time because while management roles may always be needed, intellectual roles represent ways of thinking that we want all students to adopt. Thus, the need to formalize such roles should decrease over time as students appropriate them as a matter of course when engaging in scientific investigation, Finally, it is useful to give some attention to the issue of how data will be recorded. At times it may be best to provide a table and simply have students discuss how they will use it and why it is a useful way to organize their data. At other times it may be best to have the class generate a list of possible means for recording data. Sometimes it may be sufficient to indicate that students should be sure to record their observations in their notebooks, and have the students in their groups decide what approach is best for recording their observations. lilustratiOrn. In the unit on light and shadows, Ms. Kingsley posed to her kindergarteners the question of whether an oblect's shadow can be more than one shape, following the opportunity they had to explore with flash- lights prior to beginning any formal investigation. She knew that not all the children had made shadows during their exploration, so she used part of the discussion in this phase to ascertain students' understanding of how to put objects in the light to make shadows. She showed the class how the maten- als would be set up, with a light source placed a couple of feet from a wall and a piece of poster paper taped on the wall to allow them to draw the shadows they observed. During her fourth graders' investigation of the interaction of light and matter, Ms. Lacey bridged from the children's wonderings to a question she introduced: How does light interact with solid objects? She began the pre-

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 437 paring-to-investigate phase by ascertaining students' understanding of the question. One boy asked what "interacts" means. She responded that she was interacting with the students, and then asked them to interpret the question without using the word "interact." The students responded with such questions as: "What would it do"? "How does it acts? "How does it behave"? "How do they act together (but not like in a movie)"? Ms. Lacey then solicited questions about other words in the investigation question, and a boy asked, "What is a solid?" Students responded with statements such as: "A solid is not like water "" It's filled in." "It's hard, maybe." "It doesn't bend. " At this point, Ms. Lacey picked up a bendable solid, bent it, and asked the students whether it was a solid. Students were divided on whether it was. Ms. Lacey proceeded to review states of matter with the students, discussing properties and examples. She then returned to the preparation for investi- gating light. The materials on which the students would shine a flashlight were sample, but there were many of them (more than 20 items), and describing each in order to identify it would have been cumbersome (e.g., blue plastic sheet, colorless plastic sheet, plastic sheet with gold coating on one side) so Ms. Lacey prepared a poster with each type of material mounted on it and num- bered. She used the poster to show children the materials with which they would be working, and they discussed the use of the numbers to facilitate documenting their observations. Ms. Lacey also introduced a new tool to the students: a small rectangular piece of white construction paper, which she called a "light catcher" This tool functioned as a screen to look for reflected or transmitted light. Figure 10-2 shows the setup Ms. Lacey showed the students, with the letters A and B indicating the places where the students expected they might see light. O=t ~ B Light Catr her I, FIGURE 102 Invesrigorive setup for stud ing how light inierocis with solid objects

438 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM In addition, the class talked about categorizing objects in terms of how light behaved. Ms. Lacey asked The students what dhey Thought The light might do, and they discussed categorizing The objects based on whether light bounced off, went through, became trapped, or did something else (dhe students were not sure what tills might be, but dhey wanted to have a category for odher possibilities).' In The course of dhat conversation, Ms. Lacey introduced the terms "resected," "transmitted," and "absorbed," which she stated were terms used by scientists to name the behaviors they had described. There was some discussion about what it meant when an object blocked light: Did that mean light had been absorbed, or was it simply stopped by the material? Ms. Lacey suggested that The class leave dhat ques- tion open, to be discussed again after they had investigated and had the opportunity to observe the light. Ms. Lacey chose to focus students' recording of Their observations by preparing a simple table for them to complete: a column for the number/ name of The material and a column each for indicating whedher light re- flected, transmitted (went Through), or was absorbed (trapped by) The mate- nal. The use of The table seemed straightforward, so There was little discus- sion. Ms. Lacey later noticed dhat most students used The table as though Their task was to determine which single column to check for each object. She realized dhat The students needed guidance to check for each object whether light was redected, transmitted, or absorbed. The next time Ms. Lacey taught This topic, she made two changes in tills phase. First, she was careful to raise The question of whedher light could behave in more Than one way with a matenal. Students were divided on whedher they Thought tills was possible, which gave Them a reason to investigate and supported Them in realizing The need to be Thorough in observing light with each object. Sec- ond, she asked students how they might provide evidence dhat light did not interact in particular ways widh an object. This discussion led students to realize dhat dhey would have information to record in each column of The table, and that what does not happen can be as informative as what does happen. The Investigate Phase Description. In tills phase, students interact widh the physical world, docu- ment Their observations, and drink about what These observations mean about The physical world. The teacher's role is to monitor students' use of materials and interactions with odhers (e.g., in small groups), as well as attend to The conceptual ideas with which students are working and The ways in which Their thinking is similar and different from dhat of their classmates.

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 439 Investigating involves the interaction of content and process. It may appear to students to be more about process because what we observe is a function of when, how, and widh what tools we choose to observe. At the same time, what we observe is also a function of what we expect to observe, and how we interpret our observations is clearly influenced by what we already know and believe about The physical world. For example, we have experienced children describing only one type of interaction when shining light on objects because they expected dhat light could interact in only one way. Thus They described light as only "going through" a piece of clear, colorless plastic wrap even Though we could see blight spots of light on The front of The wrap indicating reflected light. Furthermore, students described light as only "being blocked" from a piece of cardboard even though a disc of light The size of The flashlight beam could be seen on The back of The piece of cardboard, indicating that light was going Through it z2 The teacher determines whether and when to prompt students' aware- ness of The ways in which Their prior knowledge may be influencing their observations. With respea to students' interactions with mofenals, it is im- portant to monitor whether students are using them appropriately. Students invariably use materials in unexpected ways; hence, The teacher needs to observe student activity closely. When students use materials incorrectly, the teacher needs to determine whether to provide corrective feedback. Since it is important for the development of metacognition dhat students be in The "driver's seat" and not simply follow The teacher's directions, determining whedher, when, and how to provide feedback is critical. If The teacher judges that The students' activity is so off The mark dhat The targeted learning goals will be sacrificed, it is critical to provide prompt corrective feedback. An example in the study of light would be if students measuring angles of The padh of light coming into and resecting off of a mirror were using the pro- traaor incorrectly. Other cases, however, provide opportunities for students to become aware of gaps in their thinking. An example of This occurred when the teacher in The kindergarten class studying light and shadows noticed dhat some students were tracing the object directly on their recording paper - a-her Than tracing The objea's shadow. When The teacher saw This happen- ing, she joined The group as They were working and began to ask Them about Their data. In The course of The conversation, she asked Them to show her how They had made The shadows, which led Them to indicate dhat some were tracings of the objects Themselves, not The shadows. She Then asked them, "If our question is about shadows, which drawings show shadows?" The students were able to point to their drawings that were shadows. She Then asked, "How could you mark your drawings so dhat you can tell which ones are shadows, so that when we look for patterns, you'll know which drawings to look at?" They devised a scheme—to draw dots around The

440 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM drawings that were shadows and the teacher moved on to another group. Later, when the former group reported, the rest of the class learned about their strategy and how they had dealt with the "mixed" nature of their observations. Another important category of feedback is when the teacher brings out the norms and conventions of scientific investigation (e.g., holding condi- tions the same when trials are conducted, measuring from the same refer- ence point, and changing only one variable at a time). Attention to such issues can be prompted by asking students about the decisions they are making about how to investigate. For example, in the fourth-grade investi- gation of the interaction of light and matter, one group's response to Ms. Lacey's question about what they had found out revealed a lack of attention to the transr ission of light. Ms. Lacey handled this in the following way: Ms. Lacey When we were preparing to investigate, we said that light might also be transmitted, but I didn't hear you say anything about that. Did you check for that7 Student No, but we already know light doesn't go through these materials: they block it. Ms. Lacey But remember that scientists believe it is important to test out such ideas, and as scientific thinkers, your classmates will be encouraged to lookforsuch evidence. How will you convince them that these materials don't transmit lights Here Ms. Lacey gave students an important message about the need to rule out possibilities instead of relying on assumptions. With small-group investigation, in addition to general monitoring to sup- port student collaboration, the teacher needs to be attentive to whether differences in students' ideas create difficulties. In the excerpt below, two kindergarten children in Ms. Kingsley's class are investigating reflection from a mirror Their initial conflict is due to Bnan's interest in placing the mirror so that its back faces the light source. Amanda objects because her explora- tion during the engage phase revealed that reflection is best from the front of the mirror She is very interested in seeing the reflection because the class is examining a claim she made from her exploration activity, which was that you can use a mirror to make light "go wherever you want it to." Amanda [tracing line to mirrorl This goes to here. The light has to hit the mirror Then . . .

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 441 Brian Amanda Amanda Brian Amanda Brian Amanda Brian Brian I want it to go that way. [referring to placement of the mirror with its back to the light sourcel No, the mirror has to face the light source. [turns mirror to face the light sourcel Lookey! Light, see. [turns mirror back aroundl Lookey, no light, see. But that's because it's not facing that way. [turns mirror to face the lightl You said you could move it wherever you wanted it to go. So your plan has failed.... The light has to do the—okay This is the light source, rights [points to sourcel This light has to hit the mirror . . . And then, look, look, see . . . Now you think my plan works, see 7 Watch, see . . . [takes hold of mirrorl I can't make it go this way! Referring to making the light go behind the mirrorl If I take this off [removes mirror from where it rests on their drawing paperl, it's going my way. But [puts mirror back onto paperl, it's not going my way. Amanda The mirror has to face . . . The light has to hit the mirror [taps mirror with handl And look: light, light, light. [points to reflected beams of lightl But you said it could go anywhere. You said it could go anywhere you wanted it to go and I wanted it to go backwards, like this. [referring to making the light go behind the mirrorl Amanda But the mirror [forcefully places the mirror on their drawing paperl has to face the light source [forceful gesture toward light sourcel, face the light source, and THEN you can move it. [referring to the reflected beam of lightl The interaction of content and process that occurs dunng investigation means that teachers must be mindful of chi[dren's cognitive activity as they undergo and interpret their experiences with the physical world. Teachers should ask students what they are observing and what they think their ob- servations mean about the question under investigation. Sometimes it is useful to ask students why they think what they are doing Will help them answer the question. In addition, the teacher needs to observe what stu-

442 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM dents observe so students can be prompted to notice important phenomena they might otherwise ignore or be encouraged to pursue observations The teacher believes useful to The knowledge-building process. When investigative procedures are simple, students are able to focus more of dheir attention on what The data are and what These data suggest about The question being investigated. When procedures are more complex, students need more time to focus on the meaning of the data apart from The actual investigation. When students design The investigation Themselves, dhey may need to give more attention during The investigation to evaluating how well dheir plans are working so they can make adjustments. Thus, teachers need to monitor how well children are handling The complexity of The inves- tigation so that sufficient time is allocated to support The knowledge-build- ing process.33 Once The data have been collected, students need to analyze Them. Identifying patterns is a deductive analytic process in which students work from specific datasets to identify general relationships. From This step, stu- dents make knowledge claims, just as scientists would. That is, dhey make claims about the physical world, using the patterns dhey identified to gener- ate those claims. We consider This aspect of investigation to be a different instructional phase because The nature of The cognitive activity for The teacher and students has changed. This aspect is discussed as part of The preparing- to report phase. Illustration To illustrate The investigation phase, we draw upon an event That oc- curred in Ms. Kingsley's kindergarten class during dheir investigation of light and shadows. Amanda and Rochelle were working togedher, with Amanda basically directing Rochelle. When Ms. Kingsley checked on Them and asked questions to determine dheir thinking about what dhey were finding out, it became clear to her that . Amanda was quite certain that The shadow from an object could be only one shape, and Rochelle appeared to go along widh whatever Amanda Thought. While Amanda's thinking was incorrect, Ms. Kingsley chose not to intervene, recognizing That during reporting, The chil- dren would have The opportunity to see a wider range of data and possibly reconsider dheir thinking (see The illustration of The reporting phase). The following excerpt is from Ms. Lacey's fourth-grade class. This inter- change occurred early in The investigation, and Ms. Lacey was checking on a group of Three girls that she knew from previous experience had found investigative activity challenging. She began by asking which materials the students had used in their investigation and what dhey had found out. She learned That one student in The group had been working independently instead of with The o her two, and they had not been discussing dheir results.

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 443 Ms. Lacey encouraged them to work together, especially since it would be helpful to have one person holding the flashlight and material, and another person using the light catcher Ms. Lacey Mandy Ms. Lacey Mandy Ms. Lacey Mandy Ms. Lacey IPicks up a blue Styrofoam object and shines the flashlight on itl What's it doings Some goes through. How do you know7 Some blue light is on the wall. Does it do anything else7 IMs. Lacey directs the student to use the light catcher to check other possibilities.l Some is reflected. Write that down. Perhaps the most important question asked by the teacher in this ex- cerpt is "How do you know?" This question is at the core of distinguishing systematic research from our everyday sense making. It also sent the mes- sage that the students were accountable for their observations, and allowed Ms. Lacey to indicate the need to check for multiple ways in which light might behave with the object. The Prepare-to-Report Phase Description As the activity shifts to a focus on the public sharing of one's findings from investigation (reporting phase), the role of the class as a community of scientific thinkers takes on new meaning. In scientific practice, this phase marks a shift in emphasis from divergent to convergent thinking, and from operating with the values, beliefs, norms, and conventions of the scientific community in the background to operating with them in the foreground.24 Now it matters a great deal what fellow classmates will think and not just what the investigating group thinks. In this phase, just as scientists use their laboratory documents to prepare papers for public presentation to the larger scientific community, students use the information and observations in their notebooks to prepare materi- als for public presentation to their classmates. The public nature of sharing one's claims and evidence means that students need to determine the claim(s) for which there is enough evidence to warrant public scrutiny, and what data they should feature as the compelling evidence backing their own claim(s) and supporting or refuting the claims of others.

444 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM Students can use poster-size paper as the medium for reporting, thus allowing the information to be large enough for everyone in the class to see. Posters are expeaed to include a statement of the group's knowledge chim(s), as well as data backing the claim(s); if groups investigated different ques- tions, the poster should include the question as well L)ata may be presented in written, tabular, or graphical form (including figures or graphs), and stu- dents may decide to include a d agram of the investigative setup to provide a context for the data. (This is to be expected when students investigated in different ways.) As each group prepares its poster, students should be think- ing about how to present their findings to best enable others to understand them, and be convinced of the group's claim L)ecisions about how to state a claim and what d ta to include in presenting one's claim provide impor- tant learning opportunities. A major aspect of the teacher's role in this phase is to reflex the norms of the scientific community regarding the development and evaluation of knowledge claims. In the scientific community, for example, there is an expectation that relationships will be stated precisely and backed by unam- biguous and reliable data. It should also be recognized that claims can be stated in the negative, thus indicating a relationship that is claimed to be inaccurate—for example, the brightness of the light source does not affect whether light reflects from an object. Such claims help the community nar- row its consideration of possible relationships. Another role of the teacher is to help students attend to issues that may affect the quality of their public presentation. For example, teachers can encourage students to draw as well as write out their ideas to communicate them more effectively. Furthermore, teachers can prompt students to evalu- ate their poster for its effectiveness in communicating find ngs. For example: Is it readable? Are things clearly stated? Is there enough information for others to evaluate the claim or be convinced of its validity? Finally, a key role for the teacher is to monitor the types of claims students are generating and the nature of the evidence they are selecting. The teacher determines whether and to what extent to prompt students' awareness of the role played by process in determining what they observed (e.g., ascertaining students awareness of imprecise or inaccurate data). With respea to content, the teacher determines whether and when to focus stu- dents on particular strategies for interpreting or analyzing their data or to provide additional information to support students in writing claims. It may be necessary for the teacher to help groups reorganize their d ta to fund patterns. For example, Table 10-2 shows two tables. The top table shows the data as they were originally recorded. The order of the columns matches the order of places that students looked to check for light from the flashlight. The order of objects in the f ~ St column is simply the order students selected to observe them. The bottom table shows the same data in a similar form,

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 445 TABLE 10-2 Data Purposes Original Data Table Object Clear glass Purple glass Silver wrap White plastic sheet White typing paper Black felt Orange cardboard Reorganized Data Ta Tables from initial Recording and with Revisions for Analysis and Observations: On Light Catcher in Front of Object (ret lected) dim light dim purple light bright light dim light bright light no light dim orange light On Back of Object (transmitted) bright light bright purple light no light medium light dim light no light dim reddish light able and Simplified Observations: On Light Catcher Behind Object (absorbed) light shadow dark purple shadow dark shadow medium shadow medium shadow very dark shadow dark shadow On Light Catcher On Back On Light Catcher in Front of Object of Object Behind Object Object (reflected) (transmitted) (absorbed) Black felt no light very dark shadow no light Orange cardboard dim light dark shadow dim light Purpleglass dim light dark shadow bright light White plastic sheet dim light medium shadow medium light Clear glass dim light light shadow bright light Silver wrap bright light dark shadow no light White typing paper bright light medium shadow dim light but to facilitate looking for pattems, the columns and rows have been reor- dered, and the data have been simplified (information about color has been removed). This type of reorganization and simplification of data is common for scientists, and may be necessary for students to find patterns from which to make a claim. Often, the teacher's support is at the level of helping groups figure out

446 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM how best to state the claim(s) they want to make from their data. It does not include evaluating whether their data support the claim; that is part of the reporting phase and should be shared by the class. On the other hand, the teacher may choose to support students in mak- ing additional claims based on the data they have, particularly in instances where the group has unique data to make a claim that the teacher believes would promote desired knowledge-building for the class. In Ms. Lacey's fourth-grade class, for example, despite students' assumptions that light would behave in only one way with an object, a group had evidence that light behaved in more than one way. Given that this was the only group in the class making such a claim from that body of evidence, Ms. Lacey supported the group to ensure that they would include the claim in their poster so it would be introduced to the whole class. An alternative approach involves the teacher's questioning students dur- ing the prepare-to-investigate phase to lead them to consider the possibility that light may behave in more than one way. The emphasis in this case may be on ruling out the possibility of disconfirming evidence. With this ap- proach, the teacher monitors during the investigation phase whether stu- dents are checking for multiple possibilities, and will know whether the students observe light interacting with objects in more than one way. lilustratiOrn. The following excerpt from an investigation of light by third graders shows a typical teacher student interaction as students attempted to generate knowledge claims.25 The students were working with light boxes producing narrow beams of light and had been given latitude regarding which questions identified during the engagement phase they would like to study. As a result, different groups of students investigated with different types of matenals. In the transcript, note that the students did most of the talking. The teacher primarily asked questions to determine the nature of the students' thinking. Note also that the teacher reflected an important norm of scientific activity by asking the students how they planned to represent the observations supporting their claim. Don Ms. Sutton What claim are you working on right now7 We had to change it because we thought that the speed of light would be a ISecond-hand investigation|. Ms. Sutton Mm hmm. Kevin So, light can reflect off a mirror Any other object that's not a mirror, like a piece of paper Let me demonstrate. IMs. Sutton: Okay I This is a piece of paper You see, when the light hits the paper, it disappears. But before it disap-

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 447 Kevi n Ms. Sutton Kevi n Ms. Sutton Don Ms. Sutton Kevi n Ms. Sutton Kevi n Ms. Sutton Kevi n Ms. Sutton Don Kevin Ms. Sutton Kevin pears, it hits the paper, it goes through the paper Itdisappears. Ms. Sutton Hmm. Does all the light disappear through the paper7 No. Okay, you see all the light that's coming through, from this hole7 Yeah. It goes tothe piece of paper it disappears when it hits that piece—that object. Where do you think it goes7 Through the paper There's a little light over here. And it stops here because it doesn't have enough powerto go anymore. Okay. Hang on a second. So, you're saying a little bit of light goes through the paper And you think the rest of the light just disappears7 No. The rest of the light that hits the paper disappears from the light—from the object, cause it's not a mirror But if it hits the mirror it can reflect off of it. So if it's a mirror, the light goes in another direction, or reflects off. If it's something besides a mirror. . . It doesn't get reflected. It just disappears, it doesn't reflect7 Yep. Okay. Are you going to try to prove that some way to the group7 You have to show some data. Well, it's not exactly data. We sort of . . . I drew a picture out here. How could you show that7 We could get another piece of paper Save what you've got so far How could you show on another piece of paper how the light is different with differ- ent—with the mirror and with the paper7 How could you show it7 What you just said—so you could show it to the rest of the group7 We can draw the top and just say that the light is coming through—put light right here. And then the light through—going out of the box. And then we can put, make like a little part of it

448 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM like this, like the target. And put the paper right here. Ms. Sutton So, Kevin is saying, when the light hits the mirror, it looks one way. When the light hits a piece of paper, it looks another way How could you show how it looks those two ways on a piece of papers And, anotherthing is, l sort of drewthisthing. That's the light that's over here that goes there. And then when it hits these, it stays there and it doesn't come back. Ms. Sutton That's interesting, too. But you guys need to stick to one claim and deal with that. When you thin k you have evidence to r that, if you want to explore something else and have some time, you could do that. Don The Report Phase Description A critical feature of inquiry-based instruction is the point at which students' findings are publicly shared and discussed. This phase has two parts (see Figure 10-1). First, groups of students who have been inves- tigating together present their claims and evidence, which are discussed by the class in terms of their own ments and in light of the findings presented by previous groups. Second, the class discusses the commonalities and dif- ferences among the claims and evidence presented, noting claims that can be rejected, developing a class list of community-accepted claims, and de- termining claims or questions that need further investigation. In addition to providing occasions for discussing important issues related to the investiga- tive process (e.g., possible errors, missed observations), public reports re- quire students to make and defend statements about their understandings, and provide occasions for examining their own thinking and sense making as well as that of ocbersB6 In addition, when students publicly share their results, the need for vocabulary and a common language to communicate ideas becomes salient. Thus, there is an important opportunity for the teacher to support and guide students in the use of scientific terms to facilitate their communication. When students first experience this activity, the teacher plays a pivotal role in communicating and modeling expectations for audience members. This includes establishing and maintaining conversational norms L)espite the fact that children may need to challenge the ideas or work of their classmates, the teacher is key in setting the tone so that this is done with the

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 449 understanding that the students are all thinking together so They can collec- tively determine how to understand the aspect of The physical world under investigation. The primary expectations for audience members are to deter- mine whether There is a clearly stated claim that is related to the question under investigation, whether there is evidence backing that claim, and whedher The evidence is unambiguous in supporting The claim. The issue of unam- biguous support concerns whedher There is any evidence either from odher groups or from widhin The presenting group's d ta—dhat would counter The claim. Widh teacher modeling and practice widh The teacher's feedback, stu- dents become able to sustain substantive conversations regarding the knowl- edge They are developing about The physical world. The reporting phase is particularly complex and rich with opportunities for the teacher to engage in supporting children's thinking and actions. As each group shares its claim(s) and describes The relationship between These claims and Their data, The teacher assumes multiple roles: monitoring for understanding, working with The students to clarify ambiguous or incom- plete ideas, seeding The conversation with potentially helpful language or ideas, and serving as The collective memory of prior conversations (both in The whole-class context and in The small-group investigation contexts). The challenge in tills phase of instruction is to promote The group's advance- ment toward deeper understanding of The phenomenon under investiga- tion, as well as the nature of scientific ways of knowing, using The fruits of The investigation activity and The collective thinking of The classroom col~l~t~l~ity. The reporting phase culminates widh The whole class discussing The clair s that have been shared to determine which if any have sufficiently convinc- ing evidence (and a lack of contradictory evidence) to elevate Them to The status of "class claim"—indicating dhat There is class consensus about The validity of The claim. This discussion of claims typically results in identifying where There is disagreement among claims or contradictory evidence related to particular claims (e.g., when The d ta presented by one group can also be used to contradict The claim of anodher), which provides The motivation for The next cycle of investigation, ilustratiOrL Excerpts from classroom instruction illustrate various aspects of teacher and student activity during tills phase. The following transcript is from The beginning of The reporting phase in Ms. Lacey's fourth-grade class. Ms. Lacey introduces students to The class claim chart, on which The class will track The clair s that have been introduced and The classroom community's reaction to them. She also forewams students dhat they have conflicting views, anticipating The need to prepare The students to hear things from Their classmates with which they will not agree.

450 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM Ms. Lacey And we're going to start making a list of claims. Or we might have a list of—we don't knowwhetherwe believethatornot.... Some of our claims may end up being "think abouts." We need to think about them some more.... You know what7 You guys don't all agree. I've been to every group . . . so you better pay attention. They may not convince you, but you might think to yourself, "aha! I'm Donna try that." Or, "I might need to check that out." Ms. Lacey's introduction of the class claim chart sends an important message about the dynamic nature of the inquiry process: reporting is not a culminating activity; it is part of an ongoing activity, the next phase of which will be shaped by what has just transpired. Her decision to alert students to the presence of conflicting ideas provides an authentic purpose for paying attention to one another during the reporting phase and stimulated metacognition. In the next excerpt, a student questions one of the claims made by the reporting group. The group made a claim that "light can't be trapped" and cited as evidence that "you can't roll it up and throw it." The students' interaction presents the teacher with many issues to which she could react to support the students' development of scientific knowledge and ways of knowing. Bobby Megan Heather Megan Bobby Heather Bobby When you said that you believe that light can't be trapped because it's a gas, you can't roll it up and throw it. What do you meant We mean we can't grab light and throw it at someone. It's not solid. It's not a liquid, either So you're saying that light is a gas7 How do you know light is a gas7 Air is a gas, and you can't feel it. Well, you can feel it only when it's blowing. But you can't feel light because it's not blowing. So you guys are saying that you think light is a gas because light is like airs Ms. Lacey could have pointed out that a clarm about light being a gas is unrelated to the focus of this particular investigation; she could have trun-

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 451 cated the interaction by providing the information that light is a form of energy, not matter; she could have identified this claim as one that requires further exploration, perhaps in a second-hand way. But Ms. Lacey chose not to interject at all. While this decision has limitations with respect to develop- ing scientific knowledge about light, it has the advantage of giving the stu- dents opportunity and responsibility to examine one another's thinking with respect to the norms and conventions of scientific practice, as illustrated by Bobby's pressing the girls to address how they know light is a gas. Such questions can provide opportunities for students particularly interested in a question to pursue it outside of class, or resources might be brought into the class (books or descriptions downloaded from the Internet) that provide information pertinent to the question. In the next two excerpts, Ms. Lacey responds in two different ways to students' questioning of the reporting group based on her judgment of the reasons for those questions. In the first excerpt, she responds to confusion that she suspects arises from the way students are interpreting language in the phrasing of claims. The excerpt illustrates the language demands in- volved in both representing one's thinking in a claim and interpreting the claims of others. Ba ride Megan Ba ride I'm confused—"we believe light does go in a path." Well, how do you know it goes in a path7 It could go different ways. I~A path" appears to be interpreted as "one path."l We tried it on the flashlight. It's just straight. I-A path" appears to have meant "a straight path. ~ 1 Cause there's a whole bunch of light. Light can go rather waysl IshowS with handl. I~A path" appears to be interpreted as "one particular path" instead of many possible paths.l Megan We don't believe that. Ms. Lacey Can you draw a diagram on the board7 [Change from an oral to a written medium may resolve issues due to language demands.| The girls used a context from their preinstruction assessment—a tree, a person, and the sun—to show two different possibilities regarding the path of light: wavy and straight lines. They drew multiple paths from the sun and pointed to the straight lines as the representations that matched their claim. Ms. Lacey then worked with the class to modify the students' claim about the path of light so that it was consistent with the illustration:

452 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM Ms. Lacey [to classl Can you think of some way they could switch that claim to make more sense to .. g ? She's telling us one thing, and they didn't put that one word in. Ito Megan and Heatherl Cause you don't think it goes wavy, you think it goes . . . Straight. How could you change you r claim to say that7 We believe light goes only in a straight path. I to classl Will that make better sense to .. g ? Yeah. Megan Ms. Lacey Heather Ms. Lacey Class In the second excerpt, a student struggles to make sense of the claim that light reflects and goes through. Ms. Lacey suspects, because of the student's language, he has difficulty conceptualizing that light can behave in multiple ways simultaneously. As a result, she intervenes, asking a question to help achieve greater clarity regarding the student's confusion: Megan Stefan Megan Yeah. Stefan7 Reflect and go through—on the plastic tray. When you put it on reflect, it reflected off the plastic tray And when you put it on go through, itwentthrough the plastictray. But I don't get it. If it reflected off, then how did it go through7 Well, we put it on an angle and shined it and it went on ou r screen. And when we put it straight, it went th rough. Ms. Lacey Stefan, are you having a hard time thinking that light can do two things at once7 if it reflects off, why did it also go th roughs Did they explains In both of the above examples, as well as in the excerpt at the begin- ning of this chapter in which a second-grade student objected to a claim about light reflecting from wood, students are revealing that they lack a conception of light that allows it to behave in the ways indicated by other students. Brad does not have a way to think about light that would account for its ability to reflect from wood. Stefan does not have a way to think about light that would account for its ability to simultaneously reflect and pass through an object. How does some of the light "know" to reflect, while other light gets transmitted through the matenal? These are reasonable issues, and we should not be surprised that the students do not readily accept claims

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 453 that speak to a reality they do not believe. It is part of the scientific culture to be skeptical about claims that do not fit existing scientific theolies, as these claims clearly did not fit the students' preexisting ideas. Indeed, there are numerous examples of scientific papers that presented novel scientific claims and were rejected by top scientific journals because of their inconsistency with prevailing knowledge and beliefs, but later became highly regarded and even pnze-winning.27 Thus when such events occur, it is important for the teacher to recognize that the issue is the fit between the idea presented and the students' conceptual framework. As How People Learn suggests, it is precisely in these situations that students' thinking must be fully engaged if they are to develop desired scientific understanding. There are several ways to proceed in such circumstances. Some re- search has demonstrated that having students observe relationships can lead them to change their initial thinking about those relationships, or at least come up with alternative ideas.29 In the case of the second grader who was skeptical about the reflection of light, this would mean setting up the mate- nals so he could observe the reflection from wood that his classmates saw and providing opportunities to examine the reflection from other solids. Other researchers have proposed engaging students in reasoning through a series of phenomena that are closely related,30 helping students blidge analo- gous circumstances. In the case of disbelief about light reflecting from wood or other nonshiny solids, this might mean starting with observing instances of reflection that students readily accept (e.g., reflection from a mirror); linking to observations of a very thick mirror, whereby the light beam can be seen traveling through to the silvered back surface of the mirror and reflea- ing Tom there; linking to reflection from a less reflective surface, such as lead (a metal, but not shiny); then linking to a similarly less reflective surface but of a different type, such as gray construction paper; and so on. The blidging could go as far as examining reflection from black felt, a material students are initially quite sure does not reflect light, but can be observed to do so if the room is dark enough.3' Another approach to addressing the nonacceptance of claims that con- tradict everyday experience is to tell students that part of learning science means developing new conceptions of reality.32 This does not necessarily mean discarding existing ideas. 3 However, it does mean that students need to recognize that in a science context, the cultural beliefs and practices that guide knowledge production in the scientific community dictate what knowl- edge is valued and accepted and hence is considered scientific knowledge,34 and that they need to operate accordingly in their knowledge-building activ- ity during science instruction. t)espite the challenge of accepting claims that are initially counter to everyday thinking, we have regularly observed students, even very young children, developing new ideas that are counter to their initial thinking. The

454 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM following example comes from Ms. Kingsley's kindergarten class during their study of light and shadows. The class was discussing two claims that arose Mom the day's investigation and were posted on the board: (1) an object can make more than one shadow shape, and (2) an object can make only one shadow shape. When Ms. Kingsley asked the class to evaluate the claims in light of the data from students' investigations, which were also posted, Amanda, who had repeatedly stated her view that an object's shadow can be only one shape, gave the following response: Ms. Kingsley Okay, look at the evidence we've got here. Does it suppo t the claim that objects make more than one shadows Amanda Both. Ms. Kingsley You think it says both Amanda, tell me why Amanda Because um Itouching each of the posters with multiple shapes of shadowsl, all shadow, all shadow, all shadow, all shadow. Itouching each of the drawings containing only one shape of shadowl One shadow, one shadow. Here, Ar anda correctly pointed out that the data did not conclusively support one claim over the other, drawing attention to the ambiguity of the results. This provided a reason to investigate further, so the teacher sug- gested that the class do so the next day. The next excerpt is an exchange that occurred following the next day's investigation. Again, all the groups' data were posted at the front. After examining the data from the second day, all of which showed more than one shadow, Amanda provided a different evaluation of the evidence: JT Derek Amanr Ms. Kingsley We need to find out if the documentation suppo Us that a shape can make one shadow or more than one shadow. Does this evidence suppo t the claim . . . Points to the two posted claimsl More! One! Ja The first one ran object can make more than one shadowl is true. Ms. Kingsley Why7 Amanda Because one object can make more shadows, see ) Because look at all these shadows on the papers. Runs hand along all the posters because they all show multiple shapes of shadows for an objectl

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 455 of note is that Ms. Kingsley and the other teachers featured in this section allowed the children to work with the ideas they had, but pressed them to continually reexamine those ideas in light of the results of their own and others' investigations. Amanda needed the time of several cycles of investigation to become convinced of a different idea from the one she initially held. Thus, the cycling process of investigation within the same context is an important aspect of promoting desired development of scien- tific knowledge and ways of knowing, Second-Hand Investigation Our focus thus far has been on the development of understanding through first-hand investigation. Such experiences give students repeated opportuni- ties to articulate and test their reasoning and ideas against one another's fnst-hand observations, and steep them in the differences between a scien- tific approach to knowledge building from experience and a more casual everyday approach. However, inquiry-based science instruction can also profitably include learning from text-based resources (as suggested by the Na f ions/ Science Educaf ion Standards). 5 The study of accumulated knowl- edge is authentic to scientific practiced and involves cognitive activities that have many similarities with first-hand inquiry about the physical world.37 Second-hand sources can also reliably focus student attention on the core concepts of interest. The question is how to engage students in such activity in a way that keeps them actively engaged intellectually relative to scientif c ways of knowing and permits a skeptical stance that is common to a scien- tific mindset. To achieve this goal, we developed a novel type of text for inquiry- based instruction, whose use is called a second-hand investigation. These texts are modeled after the notebook of a scientist and so are referred to as notebook texts. They consist of excerpts from the notebook of a fictitious scientist, Lesley Park, who uses her notebook to "think aloud" regarding the inquiry in which she is engaged, skating with the reader her observations of the phenomenon she is studying, the way in which she has modeled that phenomenon, the nature of her investigation, the data collected in the course of her investigation, and the knowledge claims suggested by the data.33 We share excerpts from this instruction to illustrate how text can be approached in an inquiry-based fashion to support students' engagement in scientific reasoning and what role the teacher plays in such activity. The specific notebook text with which the children were working reports on an investigation with materials very similar to those used by the students in studying the interaction of light with matter, although there were several differences in Lesley's investigation, including her use of a light meter to measure the light she observed.

456 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM of note are the various ways that the teacher, Ms. Sutton, supported the students' learning from the text. For example, she led the students in a quick overview of the text during which the students identified the features that signaled this was a scientist's notebook: a header with the scientist's name and date of activity, drawings showing investigative setups, and tables of data L)unng the reading of the text, a significant amount of time was de- voted to examining the relationship between the information in the note- book and the students' own experiences. Ms. Sutton accomplished this by revisiting the claims list arising from the students' own f~rst-hand investiga- tions. The students identified those claims on which there was consensus and those that were still under consideration, but for which there was insuf- f~cient evidence. In addition, there were numerous instances in which Ms. Sutton called the students' attention to vocabulary that was introduced in the notebook text and how it compared with terms the students had been using in their own writing and discussion (e.g., Lesley's use of "absorbed" to de- scnbe the behavior students referred to as the "blocking" of light). The following three excerpts illustrate how the text, in combination with the teacher's facilitation, supported the students' engagement in scien- tific reasoning. In the f ~ St excerpt, the students have encountered a table in which Lesley presents data in units she calls `'candles." Leo Ms. Sutton Jihad Ms. Sutton Jihad Ms. Sutton Okay, it's the readout of how many candles. And right now it's showing the flashlight all by itself has. . .7 Ten candles. Ten candles. Could it be like 10.5 or something or 10.37 I would imagine. Don't you think it could go up or down depending on how bright the light is7 So, if she puts zero candles, so that means it doesn't transmit at all7 Ms. Sutton Yes. Good observation. Tatsuro Are there such thing as like, um, a millicandle7 Ms. Sutton mediated the students' sense making with the table. To un- derstand any of the other findings in this table, it was Important for the students to recognize that the amount of light from the light source (the flashlight) was "ten candles." This discussion, however, led several students to wonder about this unit of measure. Transfernng their knowledge about other units of measure, they inquired about the system from which this unit

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 457 is derived and how that system "works" (i.e., whedher it works like The metric system). In The next excerpt, The students have encountered Lesley's claim That "all objects reflect and absorb light." Ian Ms. Sutton Megan Ms. Sutton Ms. Sutton What evidence did you see that would support that tall objects reflect and absorbl even though that wasn't your claims That almost all the objects did and maybe if we used a light meter, we might have found out that every single object did a little. How about you, Megan7 Some objects did both things—two different things, but not . . . we didn't, like, kind of find 0 ut th at to r a 11 objects. If you had done more, do you think we might haven Maybe. If you had tested more7 We didn't do all the objects, yet. Megan Ms. Sutton Megan In This exchange, we see how Ms. Sutton related The second-hand inves- tigation to The students f~rst-hand investigation by calling Their attention to the differences between Their claims and Lesley's claim. This led to a discus- sion of two issues: The role of measurement and The sample size. Lesley used a light meter to collect her data, while The children had no means of mea- surement; They simply described Their visual observations as precisely as possible. Ian suggested That widh a measuring device, The class's findings might have been consistent widh Lesley's. Ms. Sutton introduced The possi- bility That additional investigation might have yielded a different finding, to which Megan responded That The class had not investigated with all the materials yet L)etermining how much evidence is enough to make a broad claim confide dy, such as "all objects reflect and absorb light," is fundamen- tal to scientific problem solving, In The following excerpt, The students entertain odher possible explana- tions for The differences between Their findings and Lesley's. In this instance, Lesley is reporting The data for what happens when a flashlight shines on a piece of black felt. She reports That no transmitted light was recorded by her light meter The majority of students, however, reported having seen trans- mitted light. Here The class considers why there might be These different findings:

458 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM Chad lan Ms. Sutton Student Ms. Sutton Tatsu ro Louise Catherine When we stuck the lamp like, not like directly next to the black but a little bit up close to the black, it came out a maroon color on the other side. Ms. Sutton So we were getting some transmitted. We thought we had some transmitted light, too. She's not getting—detecting that, is she, with her light meter7 But she would be more sure because she has a light meter and we don't. Ms. Sutton What might cause a difference in results from what you did and from what she did7 Student She may have had her flashlight back farther and we had ours up very close. Ms. Sutton Anything else might have made a differences lan7 She might have either had a weaker flashlight or a thicker piece of felt or something. Okay, so two things there. Yeah, or maybe it was because of the light meter What about the light meter7 How would the light meter make it ha rder to detect transmit- ted light7 Because it's in, measuring in the tens. What if it was like 0.097 Ms. Sutton So maybe it's not measuring to the tenth or the millicandle7 Student Or maybe she's just rounding off. Ms. Sutton Maybe she's rounding it off. Maybe the little machine rounds off. Good. Or maybe it's because like, in the diagram, it shows it had the sensor pretty far back. Maybe the transmitted light didn't go that far In this excerpt, the students began to identify the range of variables that might explain the differences between their outcomes and Lesley's, includ- ing differences in the setup, the materials, the strength of the light source, the device used to record the data, and the scientist's decisions regarding the reporting of the data. This exchange is sign if cant to the extent that the students demonstrate an appreciation for the role variables play in the de- sign of an investigation. With this understanding, they are now situated to

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 459 consider the control of variables that is necessary so that only a single con- trast is featured in an experiment.39 One final observation about the successful use of text in inquiry-based instruction is the importance of students assuming a skeptical stance rather than simply deferring to the text. The following three excerpts are illustra- tive. The first two are examples of instances in which students questioned the generality of Lesley's claim that "all objects reflect and absorb light,', In the first instance, Kit interjects, "I think that she says 'all' too much. Like she could just say 'most' or she could test more objects because 'all' is kind of a lot because she only tested like, seven." Ms. Sutton responds, "Okay, so you're saying you don't know if she's tested enough to say 'all,'to make that kind of statement." The second excerpt begins when one student, Katherine, expresses concern that Lesley has not provided sufficient information about the kinds of materials with which she investigated. This leads a second student, Megan, to observe that the objects with which Lesley investigated are quite similar (i.e., they are all "flat") and that Lesley should have selected objects with different characteristics if she wished to make the claim that "all objects absorb and reflect light." Ms. Sutton prompts for more specificity, to which Megan responds, "None of them are kind of like a ball or something that's 3-t). They're all, like, fiat . . . because something that's 3-t) . . . it gets thicker because if you had a green ball and you shine light through, it would be ,,, probably be a darker color because there's two sides to a ball and not just one." In a related criticism, Kit observes that Lesley needed to consider not only the color of the object she was investigating, but also the materiel of which it was made: Kit I don't think the claim would be as true if the white [objectsl were different materials. Ms. Sutton Okay, so you would get a—if you had a light meter to measure like she did and you were measuring all the black objects on this list, do you think you still would get different read- ings7 They'd absorb differently They wouldn't all absorb the same amounts Students Yeah yeah Ms. Sutton How many people agree with that, that all the black objects probably wouldn't absorb the same amount of lights Okay so they're agreeing with you.

460 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM SUPPORTING LEARNING THROUGH CYCLES OF INVESTIGATION Whether students' experiences with investigation are first- or second- hand, the outcome of any single cycle of investigation will not result in development of all the targeted knowledge and reasoning goals for a par- ticular topic of study. Thus, inquiry in any topic area requires multiple cycles of investigation L)iscussion of how to design curriculum units with cycles of investigation and the interplay between first- and second-hand experiences is beyond the scope of this chapter The important point is that students need to have multiple opportunities to learn concepts (i.e., multiple cycles of investigation that provide occasions for dealing with the same concepts) and encounter those concepts in multiple contexts (e.g., reflection is studied in contexts with mirrors, as well as in contexts with other opaque objects). The purpose of this section is to discuss how teachers might think about the development of knowledge across cycles of investigation, The classroom community determines the fate of any knowledge claim generated by a group. Within and across each cycle, knowledge claims are generated, tested, refuted, tweaked, embraced, discarded, and ignored. (Note that the teacher's guidance is critical to ensure that false claims are not embraced without further exploration and that core claims are understood.) Figure 10-3 illustrates this process. In this case, the class worked with five CLAIMS Cycle Cycle 2 FIGURE 103 The development of communi y knowledge across cycles of inveshgahon. Cycle 3 ~ _ synthesized knowledge claim

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 461 knowledge claims during Cycle 1 of its investigation. Following the report- ing phase, two of these claims were abandoned: one because the child who had initially championed it no longer did so, and the other because there was significant evidence countering it. Three claims survived this fast cycle of inquiry: one because there was clear and consistent data supporting it, and the other two because the data were insufficient to make a definitive judgment. The reporting phase of Cycle 2 of the investigation led to the emergence of a new claim and the abandonment of one of the initial claims because only one of nine groups presented evidence in support of that claim, and the class expressed reservations regarding that group's data collection pro- cedures. The two remaining claims survived, but were revised in ways that suggested they might be related. Cycle 3 began with the class considering three extant claims I luring the reporting phase, the two claims that appeared to be related became com- bined and synthesized into one claim. This is a significant development from a scientific perspective given the value placed on simplicity and parsimony of claims about the physical world. The final claim, while still in the running, was not accepted by the class, but neither was it rejected. This progression of events with the community knowledge claims re- sulting from each cycle is like threads that when woven together create the fablic of scientific knowledge and reasoning on the topic of study. Some threads will dangle, never fully attended to; some will be abandoned; while others will be central to understanding the topic of study and may need to be blended together to create a strong weave. The fate of each thread is determined by classroom community judgments about which claims have the most evidence, account for the greatest range of data, and are simple and concise; that is, the standards for acceptance are values adhered to by scientists in the production of scientific knowledge. Although it can be difficult for teachers to stand by while students initially make scientifically inaccurate claims, the teacher's imposition of the constraints of the scien- tific community's cultural norms norms that the students themselves even- tually enforce—results in the final set of community claims being scientifi- cally accurate or having indeterminate status with respect to science. Furthermore, whereas dangling threads in a fabric are problematic, they are important to the process of learning science because the reasons for reject- ing or abandoning claims form part of the understanding of scientif c ways of knowing. The Development of Conceptual Frameworks Imagine now that the students have been through several cycles of in- vestigation. What is to prevent these cycles from being experienced as a set

462 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM of disconnected experiences, resulting in isolated knowledge? How are the students to develop, elaborate, and refine conceptual frameworks from re- peated inquiry experiences? We have argued that the "threads that bind" take the form of explicit attention to the relationships among knowledge claims. Conclusions from How People Learn tell us that the formulation of a conceptual framework is a hallmark of developing deep understanding, and that a focus on the development of deep understanding is one of the prin- ciples distinguishing school reform efforts that result in increases in student achievement from those that do not " The development of organized knowledge is key to the formulation of conceptual frameworks L)eveloping organized knowledge is enabled by well-designed curriculum matenals, but requires specific guidance by teach ers as well. Some of that guidance needs to involve pressing students to work from the perspective of the norms for knowledge building in the sci- entific community. For example, scientists assume that there are regularities in how the world works. If the sky appears gray with no evidence of clouds or the sun, a scientist, who has seen the sun in the sky every other day, will assume that it is still there and infer that something must be blocking it. This perspective dictates different questions than one that does not assume such regularity. Another area of guidance comes from pressing students to focus on the relationships among the claims they are making. Sorting out these relation- ships may result in multiple claims being revised into a single claim, as shown in Figure 10-3. Alternatively, revisions may need to be more exten- sive to fit the expectation of scientists that relationships within a topic area fit together; that is, they are coherent with one another42 If we claim that light reflects off the front of a mirror but does not appear to reflect off the back, or if we claim that light can go through glass but does not go through a glass mirror, what is the relationship between those ideas? It is not coher- ent to claim that light does and does not reflect from a mirror Similarly, it is not coherent to say that light transmits through glass but not through a glass object (i.e., a mirror). Of course, the coherent view is that light is transmitted through glass, but in the case of a mirror, it is transmitted through the glass part but reflects from the backing that is placed on the glass to make it a mirror. To develop these kinds of perspectives, students must learn concepts in combination, with attention to the relationships among them. Illustration: The Development of Conceptual Frameworks for Light In this section we trace the development of student understanding about light over four cycles of investigation in Ms. Lacey's class, guided by the question of how light interacts with matter This instruction took place over

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 463 4 weeks, widh each cycle taking about a week of daily instruction. We present concept maps constructed from classroom discourse during The instruction,43 That is, the maps represent The collective knowledge building that would be evident to The teacher and The class. Transcnpt excerpts accompany the maps to illustrate The nature of The conversation among The students and teacher t)unng Cycle 1, students focused on the differences among objects, assuming dhat light interacted with each object in only one way L)uring reporting, they made statements such as: "Light can go Through glass if it's clear enough," "Light redects off mirrors and shiny materials, too," and "We had a solid Thing here. It just stopped at the ob ect. It didn't reflect." Students wresded with whedher claims indicating that light could "be blocked" and "stay in" meant The same Thing or somedhing different. Figure 10-4 suggests that students Thought light could interact widh matter in one of dlree ways. The question marks in the figure indicate that some individuals or groups asserted The relationships shown, but not all The students accepted These relationships, including one group that provided evidence that light can interact with an object in two ways a finding dhat could have dramatically changed The structure of The class's knowledge from what is shown in the figure. This particular group did not recognize the significance of its find- ings, focusing instead on The one way it should categorize objects from which it had observed multiple interactions. In The following excerpt, the teacher encourages the group to drink of its results as a new claim. Kevi n We saw sort of a little reflection, but we, it had mostly just see-th rough. Ms. Lacey So you're saying that some materials could be in two different categories. FIGURE 104 I REFLECTS I ~ / And? 3~1 THROUGH | | COLOR | ~3- 7=7 ~ STAYS IN I . .~ - - - -i y knowledge from ibe first cycle of investigahan If fist hand/

464 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM Derek Yes, because some were really see-th rough and reflection together, but we had to decide which one to put it in. Ms. Lacey Do you think you might have another claim here7 Light can do two things with one object. Kevin Widh The introduction of the idea that light can interact with matter in more than one way, the students embarked upon a second cycle of investi- gation widh The same matenals, with The intent of determining which if any objects exhibited The behavior claimed by Kevin and Derek. From this sec- ond round of investigation, all groups determined That multiple behaviors can occur with some objects, but the e was uncertainty about whedher These interactions occur with some types of materials and not odhers (see Figure 10-5). Nevertheless, the significance of tills day's findings is That they repre- sent a different conceptual organization from That of The first cycle (see Figure 10-4) to the extent that light is not confined to behaving in only one way. At The same time, The possibilities for The behavior of light have in- creased significantly, and only The case of four types of interaction has been ruled out in discussion by the community (following interaction comparing what different groups meant by "blocked" versus "absorbed"). LIGHT ~— E~3 INTERACTa WITH — E~E~a MATERIALa ~ Evil l `~ | block=A | FIGURE 105 Community knowledge from ibe second c cle of inveshgcfion thrsfhondl. R = refle i; T = ironsmii; A = absorb.

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 465 in addition, some students expressed puzzlement about how light could interact with a material in more than one way. In response to this question, one group introduced the idea that there was a quantitative relationship among the multiple behaviors observed when light interacted with an object: Miles Co rey Co rey If you said that light can reflect, transmit, and absorb, absorb means to block. How can it be blocked . . . and still go th roughs If just a little bit came th rough, then most of it was blocked. Ms. Lacey Would you draw him a picture, p at se ? I Corey and Andy draw setup.l Here's the light, a little being blocked inside, and a little of it comes out . . Some of it's reflecting. An dy Turing the third cycle of investigation, in which the students and the teacher interactively read a Lesley Park notebook text about light using re- ciprocal teaching strategies, :4 the students encountered more evidence that light can interact with matter in multiple ways (see Figure 10-6). This led to conversation concerning how general a claim might be made about the behavior of light: An dy Tommy An dy Can all objects reflect, absorb, and transmits Tommy7 Most of them. Co rey7 LIGHT ~ INTERACTS WITH _ ceil tAAnERIAL5 i_ —33 FIGURE 10~ Community knowledge from ibe third c cle of inveshgahon Isecond hondl

466 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM Co rey Alan Yes, because it says right in here, "Light can be reflected, absorbed and transmitted by the same object." Ms. Lacey I think we need to clarify something, because you said one thing, Corey, and Miles said something else. Andy's question was "Can all objects reflect, absorb, and transmit lights" No. It just says light can be reflected, ab- sorbed, and transmitted by the same object. It doesn't say anything about every object. Ms. Lacey So you say not all can. Do we have any data in our reading that tells us that not all things absorb, reflect, and transmits Tommy We have evidence that all objects reflect and absorb I referring to a table in the notebook textl. The concept map representing the community's understanding about light up to this point shows greater specification of the prevalence of rela- tionships ("always" versus "sometimes") and a narrowing of the possible relationships that can occur when light interacts with matter: light always reflects and is absorbed. Lesley's quantitative data about the amount of reflection and transmis- sion of light from an object as measured by a light meter supported addi- tional conversation about the issue of quantitative relationships raised by one group in the previous cycle. However, students did not yet add those ideas to their class claims chart. In the fourth cycle of investigation, students returned to a first-hand investigation and were now quite comfortable with the idea that light can simultaneously interact with matter in multiple ways. In addition, despite not having tools to compare the brightness of the light, they qualitatively compared the amount of light behaving in particular ways. This is repre- sented in the map in Figure 10-7. t)o all students have the understanding represented in Figure 10-7? The excerpt below suggests that this is unlikely. In this excerpt, a student reveals that he and his partner did not think light would reflect from an object even after the class had established in the previous cycle that light always reflects: Kenny Ms. Lacey When you saw the blue felt, is that the claim you first thoughts Yeah, we learned that this blue felt can do three—reflect, transmit, and absorb—at one, at this one object. And it did. It reflected a little, and transmitted some and it absorbed some.

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 467 / 3 LIGHT ~ if a lot R. lltile A INTERACTS WITH Em_ 2 THINGS _~ MATERIALS ~ —~ if a lot A, little R if a lot R. \ If a lot T. llille RtA FIGURE 1 07 Community knowledge from he fourth c cle of inveshgahon thrsthond} Kenny Ms. Lacey And when you started out, what did you think was going to happens That it was only going to transmit and absorb. We didn't think it would reflect. Ms. Lacey What do we know about materials and reflect- ing7 They always reflect and absorb. Class We see the teacher checking on the student's understanding, which is scientif cally accurate. But we know that for such a clarm—that light reflects off all materials—many experiences may be needed for that knowledge to be robust Relationships such as this for which we have no direa experience or that are countenntuitive (we see reflected light from objects, not the objects themselves) take time and attention, as well as recursive tacking to knowledge-building processes and the conceptual framework that is emerg- ing from those processes. Conceptual frameworks that represent the physi- cal world in ways we have not experienced (e.g., the electromagnetic spec- trum) or are counterintuitive (light is a particle and a wave) pose even greater challenges to the development of scientific knowledge. THE ROLE OF SUBJfECT-SPEC~FIC KNOWLEDGE IN EFFECTWE SCIENCE INSTRUCTION At the core of teacher decision making featured in this chapter is the need to mediate the learning of individual students. To do this in a way that leads to targeted scientific knowledge and ways of knowing, teachers must be confident about their knowledge of the learning goals. That is, teachers

468 HO W STUDENTS LEARN: SC ENCE N THE C ASSFOOM must have sufficient subject matter knowledge, including aspects of the cul- ture of science that guide knowledge production, to fully understand the nature of the learning goals. When students say that light "disappears" into paper but reflects off of mirrors, a teacher's uncertainty about whether that claim is accurate will hamper effective decision making. When students claim an object is opaque and the question at hand is how light interacts with matter, the teacher needs to recognize that the word "opaque" describes the object and not light, and that an opaque object can reflect and absorb light and even transmit some light in certain cases (e.g., a piece of cardboard). At the same time, having accurate subject matter knowledge is not suf- ficient for effective teaching. When students claim that light is a gas, it is not sufficient for the teacher to know that light is energy, not a state of matter The teacher also needs to know what observations of light might convince students that it is not a gas, which in turn is informed by knowing how students think of gases, what their experiences of gas and light have likely been, and what it is possible to observe within a classroom context. This knowledge is part of specialized knowledge for teaching called pedagogical content knowledge because it is derived from content knowledge that is specifically employed to facilitate learning. It is the knowledge that teachers have about how to make particular subject matter comprehensible to par- ticular students 4s Pedagogical content knowledge includes knowledge of the concepts that students find most difficult, as well as ways to support their understand- ing of those concepts. For example, it is difficult for students to understand that the color of objects is the color of light reflected from them because we are not aware of the reflection. Having students use a white screen to exam- ine the color of light reflected from colored objects can reveal this phenom- enon in a way that is convincing to them Pedagogical content knowledge also includes knowledge of curriculum materials that are particularly effec- tive for teaching particular topics. A still valuable resource for the study of light in the elementary grades is the Optics kit mentioned earlier that is part of Elementary Science Study curriculum materials developed in the 1960s. A teacher's knowledge of these materials and how they can be used to support knowledge building is key to employing them effectively in mediating stu- dent learning, Finally, pedagogical content knowledge includes ways to assess student knowledge. A classic item to determine students' understanding of how we see is a diagram with the sun, a tree, and a person looking at the tree.4 Students are asked to draw lines with arrows in the diagram to show how the person sees the tree. Arrows should be drawn from the sun to the tree to the person, but it is not uncommon for students to draw arrows from the sun to the person and the person to the tree. Use of this item at the beginning of a unit of study can provide a teacher with a wealth of information on current

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 469 student thinking about how we see, as well as stimulate students to wonder about such questions. The more teachers know and understand about how their students think about particular concepts or topics of study, how that thinking might de- velop and unfold during systematic study of the topic, and how they might ascertain what students' understanding of the topic is at any point in time, the better they are able to optimize knowledge building from students' var- ied experiences and support students in developing desired scientific knowl- edge and ways of knowing. When and how to employ particular strategies in the service of supporting such knowledge building is a different issue, but the topic-specific knowledge for teaching that is identified as pedagogical content knowledge is a necessary element if students are to achieve the standards we have set. CONCLUSION Science instruction provides a rich context for applying what we know about how people team. A successful teacher in this context is aware that he or she is supporting students in activating prior knowledge and in building upon and continuing to organize this knowledge so it can be used flexibly to make sense of and appreciate the world around them. To do this well, the teacher must be knowledgeable about the nature of science, including both the products the powerful ideas of science—and the values, beliefs, and practices of the scientific community that guide the generation and evalua- tion of these powerful ideas. Fur he neon e, teachers must be knowledgeable about children and the processes of engaging them in knowledge building, reflecting upon their thinking and learning new ways of thinking. We have proposed and illustrated a heuristic for conceptualizing in- struction relative to the opportunities and challenges of different aspects of inquiry-based instruction, which we have found useful in supporting teach- ers in effective decision making and evaluation of instruction. We have ar- gued that the development of scientific knowledge and reasoning can be supported through both first- and second-hand investigations. Furthermore, we have proposed that the teacher draws upon a broad repertoire of prac- tices for the purposes of establishing and maintaining the classroom as a learning community, and assessing, supporting, and extending the knowl- edge building of each member of that community. All of these elements are necessary for effective teaching in the twenty-first century, when our stan- dards for learning are not just about the application of scientific knowledge, but also its evaluation and generation.

470 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM NOTES 1. Schwab, 1964. 2. Hapgood et al., in press; Leh¢r et al., 2001; Magmusson et al., 1997; Metz, 2004. 3. National Research Counci, 2003. 4. These materials, onginally developed in the 1960s, can be purchased from Delta Education: http://www. delta-education. com/. Whereas some view conceptual change as referring to a change from existing ideas to new ones, we suggest that new ideas are often developed in parallel with existing ones. The new ideas am rooted in different va ues and beliefs those of the scientific community rather than those guidmg our dai y lives. Chi, 1992. Gall i and Hazan, 2000. Our decision to focus on irst Action in which investigation is central ref ects the national standard that Cal s for science irst Action to be inqui y based. 9. We use the temm "guided" inquiry to sigmal that the teacher plays a prominent role in shaping the inqui y expenence, guiding student thinking and activity to enable desired student learning from investigation. 10. Magmusson and Palincsar, 1995. 11. Bames, 1976; Bybee et a ., 1989; Karplus, 1964; Osborne and Freyberg, 1985; Lehrer and Schauble, 2000. 12. A of the lost Action featured in this chapter was conducted by teachers who we¢ a part of GlsML Community of Practice. a mu uyear professional devel- opment effort aimed at identifying effective practice for inquiry-based science teaching. 13. This discussion draws on a study focused on children's self-regulation during science lost Action, which took place in a school in a relatively small distdct (about 4,600 students) that includes a state university. Approximately 45 per- cent of the students in this district pass the state standardized tests, and 52 percent are economically disadvantaged. 14. This class is in a school in a relatively small district (about 3,000 students) near a major industdal plant in a town with a state university. Approximately 38 percent of the students in this district pass the state standardized tests, and 63 percent are economically disadvantaged. 15. Whi e we are featuring contexts in which there is a sing e question, teachers could choose to have a context in which children am investigating different questions related to the same phenomenon. However, it is impo tant to ecog- nize the substantially greater cognitive and procedural demands this app oach places on the teacher, so it is not something we recommend if a teacher is inexperienced in conducting inqui y-based irst Action. 16. A though it can be motivating and conceptually beneficial for students to be placed in the mle of generating questions for investigation, the teacher needs to be mindful of the consequences of taking time to investigate questions that may be trivial or peripheral to the unity of study. The teacher may judge the time to be useful as students can sti l learn a gnat deal about investigation, but

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 471 the teacher also may seek to ¢shape the question so it is not so conceptually distant as to sidetrack the focus relative to the desired content Boa s. 17. Hapgood et al., in puss; Lehrer et a ., 2001; Metz, 2004. 18. This person monitors the time the group is taking for the investigation to support the students in examining how efficient y they are working and decid- ing whether it is necessary to adjust the tempo of their activity to finish m the allotted time. 19. It is very reasonable for the teacher to d scuss these issues with the whole class dunng the preparing to mvestigate phase and to invite the class to specify procedures. . ~ddnessing these matters with the whole c ass gives the teacher opportunities to model thinkmg for the benefit of all. However, whi e this is enabling for students when they are quite new to investigating, it constrains students' development of the knowledge and skills needed to make these decisions independent y. Thus it is important for the teacher to give students an opportunity to make these types of decisions on their own during some investigations. 20. Herrenkoh et al., 1999. 21. The students inadvertent y interpreted the idea of categorizing to mean that light would behave in on y one way with each object. This led many students to stop observing an object as soon as they had identified one way light be- haved with it. 22. In both cases, the fact that we can see the object tel s us that light is ref ected. However, students had not yet established that relationship, so we Refer hem on y to the direct evidence of light. 23. Blumenfeld and Meece, 1988. 24. Magmusson et al., in press. 25. This class is in a moderately sized distdct (about 16,700) students) in a town with a major university. Approximately 70 percent of the students m this dis- tdct pass the state standardized tests, and 16 percent are economically disad- v mtaged. 26. Blown and Campione, 1994; Palincsar et al., 1993. 27. Campanario, 2002. 28. Osborne, 1983. 29. Magmusson et al., 1997. 30. C ement, 1993 31. We observed a group of children in a fou th-grade class working very ha d to determine if black felt ref ects light. They piled their matena s in the bathroom m the classroom, taped around the door to block out any light, and studied the black felt. They were quite proud to Report their evidence that it did indeed reflect light 32 Chi. 1992 33 Mouthed. 1995 34. Driver et al., 1994. 35. National Research Council, 1996. 36. Crawford et a., 1996. 37. Magmusson and Pa incur, m pness-b.

472 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM 38. See Magnusson and Palincsar (in press-a) for discussion of the theory and principles underlying the development of these texts; Pa incsar and Magmusson (2001), for a more complete description of Lesleys notebook and of research investigating the use of these notebook texts; and Magnusson and Pa incsar (in press-b) for a discussion of teaching from these notebook tests. 39. K ahr et al., 2001. 40. Magmusson et al., in press; Palincsar et al., 2001. 41. Newmann et a ., 1995. 42. Einstein, 1950. 43. Ford, 1999. 44. Pa inapt and Blown, 1984. 45. Magmusson et al., 1999; Wi son et al., 1988. 46. Eaton et al., 1984. REFERENCES Barnes, D. (1976). From communication to curriculum Hammondswo th, UK Pen- guin Books. Blumenfeld, P. C., and Meece, J.L. (1988). Task factors, teacher behavior, and stu- dents' involvement and use of learning strategies in science. Elementary 5< hool Journal, 88(3), 235-250. Brown, A.L., and Campione, J.C. (1994). Guided discovery in a community of leam- ers. In K. McCii Iy (Ed.), Classrooms lessons integrating cognitive theory and classroom practice (pp. 229-272). Cambndge, MA: MIT P¢ss. Bybee, R. W., Buchwald, C E., Cnssman, s., Hell, D R., Kuerbis, PJ., Matsumoto, C., and Mclnerney, J.D. (1989). Science and technology education for the elemen- tary years Frameuorksfor curriculum and instruction. Washington, DC: Na- tional Center for improving Science Education. Camp ma-do, J.M. (2002). The parallelism between scientists' and students' resistance to new scien~ifrc ideas. InternationalJournal of ScienceEducation, 24 10), 1095- 1110. Chi, M.TH. (1992). Conceptual change within and ac 055 ontological categories: Examples f om learning and discovery in science. In R Giere (Ed.), Cognitive models of science Minnesota studies in the philosophy of science (pp. 129 186). Minneapolis, MN: University of Minnesota P¢ss. Clement, J. (1993). Using bridging analogies and anchonng intuitions to deal with students' preconceptions in physics. Journal of Research in Science Teaching, 30, 1241-1257. C awfo d, s Y., Hu d, J.M., and Weller, A.C. (1996). From print to electronic The transformation of scientific communication. Medford, NJ: Infommation Today. Dnver, R. Asoko, H., Leach, J., Alortimer, E, and Scott, P. (1994). Const Acting scien- tific knowledge in the c asstoom. Educational Researcher, 23 7), 5-12. Eaton, J.F, Anderson, C.W., and Smith, E L. (1984). Students' misconceptions inter- fe¢ with science learning: Case studies of fifth-g ade students. Elementary Sckoo/ Journal, 84, 365-379. Einstein, A. (1950). Out of my lateryears. New York Phi osophical Library.

TEACH NG ABOUT SC ENCE AND L GHT N EEEMENTAFY GRADES 473 Fo d, D. (1999). The mle of text in supporting and extending first-hand investiga- tions in guided inquin science. DissertationAbstractsinternational, 6a7), 2434. Gall i, 1., and Hazan, A. (2000). Leamets' knowledge in optics: interpretation, st uc- ture and analysis. InternationalJournal of ScienceEducatSon, 221), 57-88. Hapgood, S., Magmusson, SJ., and Palincsar, A.S. (in press). Teacher, text, and expe- nence: A case of young chi d¢n's scientific inquiry. Journal of the Learning Sciences Her¢nkoh, L., Palincsar, A.S., DeWater L.S., and Kawasaki, K. (1999). Developing scientific communities in classrooms: A sociocogmitive approach. Journal of the Learning Sciences, 8(3-4), 451-494. Karplus, R. (1964). Theoretical background of the science curriculum improvement study Berkeley, CA: Science Curriculum Improvement Study, University of Cali- fornia. K ahr, D., Chen, Z., and Toth, E. (2001). Cogmitive development and science educa- tion: Ships that pass in the night or beacons of mutual illumination? In S. Carver and D. K ahr (Eds.), Cognition and instruction Twenty-f ve years of progress (pp. 75-120). Mahwah, NJ: Lawrence Erlbaum Associates. Leher, R., and Schauble, L. (2000). Modeling in mathematics and science. In R. Glaser (Ed.), Advances in instructSonalpsychology, sol 5 Educational design and cognStSue science (pp. 101- 159). Mahwah, NJ: Lawrence Erlbaum Associates. Lehrer, R., Schauble, L., and Petrosino, ~ J. (2001). Reconsidering the mle of expen- ment in science education. In K. Cmwley, C.D. Schunn, and T. Okada (EdS :), Designing for science Implications from everyday, cat room, and professional settings Mahwah, NJ: Law¢nce Erlbaum Associates. Magnusson, SJ., and Palincsar, A.S. (1995). The learning environment as a site of science education reiomn. Theory into Practice, 34(1), 43 50. Magmusson, SJ., and Palincsar, A.S. (in pess-a). The application of theory to the design of innovative texts supporting science inst Action. In M. Constas and R. Sternberg (Eds.), Translating educational theory and research into practice. Mahwah, NJ: Lawrence Erlbaum Associates. Magmusson, SJ., and Palincsar, A S. (in press-b). Learning f om text designed to model scientific thinking. In W. Saul (Ed.), Crossing borders in literacy and science instruction Perspectives on theory and practice Newark, DE: Interna- tiona Reading Association. Magmusson, SJ., Templin, M., and Boyle, R.A. (1997). Dynamic science assessment: A new approach for investigating conceptual change. Journal of the Learning Sciences, 6 1), 91-142. Magnusson, SJ., Borko, H., and K ajcEk, J.S. (1999). Nature, sources, and develop ment of pedagogical content knowledge for science teaching. In J. Gess-Newsome and N. Lederman (Eds.), Science teacher knowledge Dordecht, The Nether- lands: K uwer Academic. Magmusson, SJ., Palincsar, A.S., and Templin, M. (in press). Community, culture, and conversation in inquiry-based science instruction. In L. Flick and N. Ledemman (Eds.), scientific inquiry and the nature of science 1.77plicahon~ for teaching, learning, and teacbereducation. Dord¢cht, The Netherlands: K uwer Academic.

474 HOW STUDENTS LEARN: SC ENCE N THE C ASSFOOM Metz, K E. (2004). Ch d¢n's understanding of scienti lo inquiry: Their conceptualization of unce tamty in investigations of their own desigm. Cognition and Instruction, 22 2), 219-290. Mortimer, E.F (1995). Conceptual change or conceptual pro lie change? Science and Education, 4, 267-285. National Research Council. (1996:). National science education standards. National Committee on Science Education Standards and Assessment, Center for Science, Mathematics, and Engineering Education. Washington, DC: National Academy Press. Nationa Research Council. (2003). Lo urn in. 7 a no 1 SnstructSon:ASERPresearci agenda. M.S. Donovan and J.W. Pellegnno (Eds.), Panel on Leaming and Inst Action, Strategic Education Research Partnership. Washington, DC: The Nationa Acad- emies Press. Newmann, FM., Marks, H.M., and Gamotan, A. (1995). Authentic pedagogy: Stan- dards that booststudentperformance (Issue Report #8, Center on Organization and Rest ucturing of Schools.) Madison, W: Wisconsin Center for Educational Resea ch, University of Wisconsin. Osborne, R. (1983). Towards modifying children's ideas about electric curnent Re- seareb in Science ~ Technological Education, 1(1), 73-82. 0s700me, R., and F¢yberg, P (1985). LearnSngSnscSence TbeSmp/ScatSonsoicbS/dren's science Portsmouth, NH: Heinemann. Palincsar, A.S., and Brown, ~ I.. (1984). Reciprocal teaching of compehension-fos- tenng and monitoring activities. Cognition and Instruction, 1, 117-175. Palincsar, A S., and Magmusson, SJ. (2001). The interplay of first-hand and text-based investigations to model and support the development of scientific knowledge and reasoning. In S. Carver and D. K ahr (Eds.), Cognition and instruction Twentyf He years of progress (pp. 151-194). Mahwah, NJ: Lawrence Erlbaum Associates. Palincsar, A S., Anderson, C A., and David, YM. (1993). Pursuing scientific literacy in the midd e g odes through co 7aborative problem solving. Elementary School Journal, 93(5), 643 658. Palincsar, A S., Magnusson, SJ., and Hapgoor7. S. (2001). Track cuing ideas through it e rotaries of science instruction: React ers'dSscourse moues and their reSation- shipstochisdren's learning Paperp¢sented at the a nual meeting of the Amencam Educationa Resea ch Association, Seatt e, WA. Schwab, JJ. (1964). St rectum of the disciplines: Meanings and sigmiOcances. In G.W. Ford and L. Pugmo (Eds.), The structure of knowledge and the curriculum (pp. 6-30). Chicago, IL: Rand McNally. Wilson, S.M., Shu man, L.S., and Richert, E.R. (1988). '150 different ways' of knowing: Repnesentations of knowledge in teaching. In J. Calderhead (Ed.), Exploring teachers thinking. New York: Taylor and Francis.

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How Students Learn: Science in the Classroom builds on the discoveries detailed in the best-selling How People Learn. Now these findings are presented in a way that teachers can use immediately, to revitalize their work in the classroom for even greater effectiveness.

Organized for utility, the book explores how the principles of learning can be applied in science at three levels: elementary, middle, and high school. Leading educators explain in detail how they developed successful curricula and teaching approaches, presenting strategies that serve as models for curriculum development and classroom instruction. Their recounting of personal teaching experiences lends strength and warmth to this volume.

This book discusses how to build straightforward science experiments into true understanding of scientific principles. It also features illustrated suggestions for classroom activities.

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