How Students Learn Science in the Classroom (2005) / Chapter Skim
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10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level
10 Teaching to Promote the Development of Scientific Knowledge and Reasoning About Light at the Elementary School Level
Pages 53-106
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From page 53... ...
How do we help students develop scientific ideas and ways of knowing? ' 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.
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From page 54... ...
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.
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From page 55... ...
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)
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From page 56... ...
- 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.
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From page 57... ...
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 observe. For this reason, The approach to teaching we suggest in this chapter provides students with a great many opportunities to make and test knowledge claims, and to examine The adequacy of Their own and adhere reasoning in doing so.
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From page 58... ...
The opportunity for repeated cycles of investigation allows students 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, participation 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 investigations do not always lead to observations and experiences That support The targeted knowledge.
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From page 59... ...
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)
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From page 60... ...
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 represented by the inner loop is on testing explanations.
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From page 61... ...
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 conditions is a hallmark of the practice of science, and that evidence not obtained under those conditions would lead scientific thinkers to be skeptical about the knowledge claim.
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From page 62... ...
. 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 matter7)
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From page 63... ...
TABLE 10-1 Fourth Graders' Initial Ideas About Light Light travels. Light travels in a curved path.
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From page 64... ...
Like, in the first hand, the white light blends with .
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From page 65... ...
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.
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From page 66... ...
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.
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From page 67... ...
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)
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From page 68... ...
She showed the class how the matenals 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.
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From page 69... ...
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.
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From page 70... ...
In tills phase, students interact widh the physical world, document 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)
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From page 71... ...
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.
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From page 72... ...
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 exploration 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.
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From page 73... ...
[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.
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From page 74... ...
From This step, students make knowledge claims, just as scientists would. That is, dhey make claims about the physical world, using the patterns dhey identified to generate those claims.
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From page 75... ...
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.
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From page 76... ...
In the scientific community, for example, there is an expectation that relationships will be stated precisely and backed by unambiguous 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.
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From page 77... ...
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)
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From page 78... ...
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.
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From page 79... ...
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.
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From page 80... ...
, public reports require 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.
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From page 81... ...
The reporting phase culminates widh The whole class discussing The clair s that have been shared to determine which if any have sufficiently convincing 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.
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From page 82... ...
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.
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From page 83... ...
While this decision has limitations with respect to developing scientific knowledge about light, it has the advantage of giving the students 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)
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From page 84... ...
Lacey Heather Ms. Lacey Class In the second excerpt, a student struggles to make sense of the claim that light reflects and goes through.
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From page 85... ...
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 contradict 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 knowledge is valued and accepted and hence is considered scientific knowledge,34 and that they need to operate accordingly in their knowledge-building activity during science instruction.
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From page 86... ...
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.
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From page 87... ...
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.
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From page 88... ...
Sutton mediated the students' sense making with the table. To understand 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)
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From page 89... ...
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 .
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From page 90... ...
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, including 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 design of an investigation.
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From page 91... ...
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.
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From page 92... ...
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.)
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From page 93... ...
This progression of events with the community knowledge claims resulting 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.
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From page 94... ...
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 principles 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)
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From page 95... ...
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)
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From page 96... ...
. 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.
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From page 97... ...
. 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.
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From page 98... ...
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 transmission of light from an object as measured by a light meter supported additional conversation about the issue of quantitative relationships raised by one group in the previous cycle.
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From page 99... ...
take time and attention, as well as recursive tacking to knowledge-building processes and the conceptual framework that is emerging from those processes. Conceptual frameworks that represent the physical world in ways we have not experienced (e.g., the electromagnetic spectrum)
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From page 100... ...
Having students use a white screen to examine the color of light reflected from colored objects can reveal this phenomenon in a way that is convincing to them Pedagogical content knowledge also includes knowledge of curriculum materials that are particularly effective 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.
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From page 101... ...
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.
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From page 102... ...
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.
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From page 103... ...
Approximately 70 percent of the students m this dis tdct pass the state standardized tests, and 16 percent are economically disad v mtaged.
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From page 104... ...
. Conceptual change within and ac 055 ontological categories: Examples f om learning and discovery in science.
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From page 105... ...
. Nature, sources, and develop ment of pedagogical content knowledge for science teaching.
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From page 106... ...
. Track cuing ideas through it e rotaries of science instruction: React ers'dSscourse moues and their reSationshipstochisdren's learning Paperp¢sented at the a nual meeting of the Amencam Educationa Resea ch Association, Seatt e, WA.
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