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7
Learning from Science Investigations
In this book we have described how engaging children in scientific practice supports student learning in K-8 classrooms. The investigations in these classrooms typically unfold over several weeks or months. In pursuit of scientific answers, students engage in practices akin to those of real scientists, such as posing scientific questions, using data to examine complex phenomena, and generating explanations to account for their observations. These activities are often difficult even for professional scientists, who have access to complex social networks and well-resourced labs, let alone K-8 students. Yet there is compelling evidence that when classrooms function to support real scientific practice, students’ understanding of science can flourish.
Supporting student learning in regard to scientific investigations requires deliberate and consistent instructional efforts. Research shows that simply “doing” science activities often leaves students with an inaccurate sense of what science is and how it works. To build their science knowledge and skill across the strands—learning scientific explanations, generating scientific evidence, reflecting on scientific knowledge, and participating in the social processes of science—requires intentional, sustained instruction and support. In this chapter, we focus on the kind of support that teachers can provide students to enable them to learn from their own scientific investigations. We examine several practices that effective teachers, in collaboration with researchers, have developed to help students do science in a “minds on” way.
Creating Meaningful Problems
At the root of all science investigation are complex and compelling problems. In order for problems to be effective for supporting learning, they must be meaningful both from the standpoint of the discipline and from the standpoint of the
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learner. If a problem fails to connect to legitimate and fundamental scientific ideas, it cannot be used to promote science learning. And if students fail to see the problem as meaningful, there is little chance that they will engage in the range of productive scientific practices that result in science learning.
Scientifically meaningful problems are framed by core concepts, such as biodiversity, the atomic-molecular theory of matter, and evolutionary theory, and they typically focus on the smaller concepts within those core ideas. Scientifically meaningful problems may be theoretical or practical. Theoretical problems are framed in terms of basic scientific ideas: How can matter be transformed? Why do objects lie at rest on the earth’s surface unless disturbed? Why are some species successful while others fail?
Practical or applied problems engage students in solving real problems in more immediate ways. For example, a unit on leverage and mechanical advantage might challenge students to think about and explore how a child could raise an adult off the ground using only a piece of 2 × 4 lumber as a lever and a cinder block as a fulcrum. Students might also engage in the application of science to broader societal issues. For example, they might explore the impact of an invasive species on a local woodlot and consider how to intervene to preserve the health of the local ecosystem. They might study the impact of a regional health problem, such as childhood obesity or asthma, and build a strategy for educating the community about risk prevention and treatment.
In addition to being scientifically meaningful, investigations must be meaningful to the person conducting the investigation. But what does it mean for a problem to be meaningful to a K-8 student? A meaningful problem must present an opportunity for something to be gained—practically or intellectually or both—from the investigation or outcome. In some cases, the benefits of solving a problem are easily recognized. For example, in the lever and fulcrum investigation, the problem posed and the resulting solution or outcome will be fairly easy for students to identify and appreciate. Students may also relate more easily to the curious phenomena they observe in their daily lives, such as what causes an empty juice box to crunch up when you suck continuously through a straw.
However, many concepts and problems worthy of investigation cannot be as easily linked to students’ own experiences, their existing knowledge, or issues they are familiar with and care about. In these cases, students may be less motivated initially to find meaning in a problem, and they may need to know more about it in order to become motivated to find that meaning. For example, many students
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may not immediately recognize the problem of the impact of an invasive species on a local woodlot as one they should care about. They might require additional information about why this problem should matter to them, such as having the teacher illustrate the concept of interdependence in ecosystems—that is, showing that all species, including humans, are linked and therefore the impact of an invasive species has broad and important implications. In this way, a bridge is built between what students do know and do care about and the problem they are attempting to make a meaningful connection with. For example, a study of the motion of light (a common topic in the K-8 curriculum) might require that students first recognize that the motion of light is critical to understanding how telescopes, eyes, and cameras function. Subsequent lessons on such topics as describing and modeling light motion with vector diagrams may then be presented in an investigative context that students see as meaningful.
Sequencing Meaningful Instruction
In order for problems to continue to be meaningful throughout an investigation, careful thought must be given at the outset to how to sequence instruction. Students will need to develop their ability to work on increasingly complex problems, including gradually acquiring knowledge of the concepts being studied and the specific skills needed to carry out a given investigation. A common but limited approach to sequencing investigations has been to teach the content related to the investigation first, and afterward to do the investigation in order to validate the content. This approach is counterproductive on a number of levels. First, it fails to give students a clear idea of why a particular investigative strategy is being used for that particular problem. It also emphasizes and promotes the false dichotomy between scientific content and process, leaving students with the misconception that scientific practice is algorithmic or procedural. Finally, it fails to recognize the critical aspects of science identified in Strand 3 and Strand 4, namely, the importance of reflecting on one’s own scientific knowledge over the course of an investigation and the role of peers in building scientific arguments.
A more productive approach is to intentionally build the appropriate scientific knowledge and skills “just in time,” at strategic points throughout the investigation. When presented at the point in the investigation at which they can be applied, new ideas, as well as new investigative skills and techniques, will be framed in a more meaningful context. In many cases, students will need quick
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access to some basic concepts in order to see a problem and investigation as meaningful. Over time, they will require additional skills as the investigation advances: they may need a method for collecting relevant data and then a method for analyzing the data. They will almost certainly need structured support in building the logical links that help move them from data to scientific explanation, as well as help them reflect on what they’ve learned in light of previous observations. Like the problems themselves, these and other skills need to be made meaningful to students, and presenting them in the context of a problem to which they can be readily applied helps students understand their utility.
Recently researchers have developed very promising results from building and testing science curriculum units that, from the outset, engage students with problems they will investigate over the course of several weeks or months. These units sequence lessons to gradually build students’ knowledge and skill over time so that they arrive at each phase in an investigation prepared to engage in the necessary work.
“Struggle for Survival” is a six- to seven-week classroom science investigation that supports the learning of core evolutionary concepts. Developed as part of the Biology Guided Inquiry Learning Environments (BGuILE) project at Northwestern University, the unit is designed to support the learning of core concepts in evolutionary biology.1 Using software that depicts a prolonged drought on the Galapagos Island Daphne Major, students investigate how the drought affects the animal and plant populations on the island. They learn background information about the island, read through the field notes of researchers, and examine quantitative data about the characteristics of the island’s species at various times to look for changes in the populations.
The unit unfolds over four phases, which are sequenced to gradually increase the demands of the learning experiences and the sophistication of students’ reasoning about core concepts. The students are presented with a problem at the beginning of the unit—the finch population on the island has declined precipitously. Their job is to examine a range of evidence to determine what has caused this decline. Within this framework, students engage in a study of the problem over a period of approximately six weeks to advance their understanding through reading, posing questions, data analysis, presentation, and debate.
The first phase (10 classes) sets the stage by probing students’ existing knowledge of natural selection, by providing requisite background knowledge about ecosystems and the theory of natural selection, and by building student motivation. In the second phase (five classes), students learn about the Galapagos
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Islands and the methods scientists use to study ecosystems. They generate initial hypotheses, work with a small data set, and learn about the computer system they will use in the major investigation. These first two phases of the investigation illustrate how foundational knowledge is built on in the context of an investigation. Although from the very beginning students are presented with the challenge of explaining a shift in finch population, they do not dive immediately into collecting and analyzing data. Instead, they begin by building their understanding of the specifics of the case and key principles of biological evolution.
Only after completing these initial 15 lessons do the students begin to work with the natural selection data set. Having immersed themselves in the problem and having built the theoretical knowledge and skills they will need to advance the investigation, they begin the third phase of the unit (10 classes). In this phase, students explore the data set, generate explanations for observed patterns of change in the finch populations, and critique the explanations of their classmates. In the fourth phase (six classes), student teams prepare reports, present findings, and analyze key points of agreement and disagreement across reports.
Sequencing a Unit on Natural Selection
Four Phases of Learning
Phase 1
General Staging Activities
Determine what students know, provide background knowledge, build student motivation (10 classes).
Phase 2
Background for Investigations
Gather information, generate initial hypotheses, work with small data set (five classes).
Phase 3
Software Investigations
Investigate data, generate and critique explanations for observations (10 classes).
Phase 4
Presenting and Discussing Findings
Prepare reports, present findings, analyze key points (six classes).
Carefully sequenced experiences such as these provide a road map for students, and they build just-in-time skills and knowledge that allow them to work through complex problems for which their knowledge and skill have immediate application. Students experience important elements of scientific practice as they wrestle with evidence, consider different ways of looking at phenomena and interpreting evidence, and work collectively to determine what they understand and which interpretations they find compelling. Students are not sent off on an unguided exploration of a phenomenon or question but are presented with intentionally sequenced and supported experiences framed in a sustained investigation of a central problem. This allows them to build knowledge about core aspects of biological evolution while building their skills and ability to work with data, learn with their peers, and present arguments using scientific language conventions.
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Constructing and Defending Explanations
The science curriculum in most school systems focuses narrowly on “final form science”—the collection of scientific findings that populate textbooks. When students are given opportunities to “do” science, these experiences are often presented as experiments with predetermined steps and findings. In other instances, science investigations take the form of “activity mania” in which students complete activities that lack purpose and input from teachers.
Productive investigations are not sequentially scripted. Nor are they unguided. They do not simply unfold when students are given materials and opportunities to work on scientific problems. Rather, they are structured and regulated by the teacher, who plays an active role in the investigative experience. In order for investigations to be successful, teachers must work to make student activity purposeful, to build social interaction that supports cognitive processes, and to focus their efforts on pushing students’ thinking about science toward increasingly sophisticated levels. Teachers and researchers have found ways to structure and script aspects of scientific investigations so that, over time, students gradually acquire scientific modes of thinking and interacting, drawing on these to learn science. They have also found promising ways to teach students fundamental practices for developing scientific explanations, as well as ways to integrate these practices into students’ ongoing work.
We have discussed a science unit from the BGuILE project called Struggle for Survival. It is drawn from a research and design initiative called Investigating and Questioning Our World through Science and Technology (IQWST). The goal of IQWST is to design middle school science curricula that support the scientific practices of explanation and argument as learners engage in project-based inves-
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tigations.2 The IQWST units are designed to teach both scientific principles and the scientific practices of constructing and defending explanations by providing students and teachers with a framework that clearly defines this complex practice. The framework includes three components:
Claim:
What happened, and why did it happen?
Evidence:
What information or data support the claim?
Reasoning:
What justification shows why the data count as evidence to support the claim?
Thus, the curriculum helps students make sense of the phenomena under study (claim), articulate that understanding (evidence), and defend that understanding to their peers (reasoning).
As described earlier, part of the Struggle for Survival unit includes a two-week project in which students investigate a database holding information about the finch population on the Galapagos Islands. Students work in pairs in order to interpret the computer data and determine why so many finches died during the dry season of 1977 and why some were able to survive. The scientifically supported explanations for this question use data to identify which trait variations enabled birds to differentially survive the drought. For example, one response could state that the birds that survived the drought had longer beaks, which enabled them to crack the harder seeds that also survived the drought. Another plausible argument consistent with the data (but scientifically less accurate) could be that the birds that weighed more had fat stores that made them better able to survive the food shortage resulting from the drought.
Below is an excerpt from a student group presentation in which students use the claim-evidence-reasoning framework to reflect on their analysis and explain their current thinking about the investigation.
Evan:
“Again, the question we had through this entire project, which does not have one simple answer, is: in 1977, why did 40 percent of the finch population die in Daphne Major in the Galapagos Islands, and why did the ones that survive, survive? This is our report. I’m Evan, this is Leona, and this is Nelly. Here we go.”
Leona:
[Reading from a poster] “We have a few theories. In concluding our research concerning the study of finches on the island, our focus is to find out why the population of finches on that
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island dropped dramatically in 1977. We believe the cause of the decrease in the population began with the change in the weather situation in Daphne Major. In 1977 we saw that there was an amazing lack of rainfall compared with the year before (1976). Here is the graph that shows the years and the different changes. [She points to the graph.] There were 167 centimeters of rainfall in the wet season of 1976, but there were only 20 centimeters of rainfall in the wet season of 1977. The lack of rainfall caused a decrease in plant life, because of the fact that all plant life, including cactus, lives off water or rainfall.
For example, in the dry season of 1976 there were 130 portulaca seeds on the island, but in the dry season of 1977, when there was absolutely no rain, there were no portulaca seeds whatsoever. This is the chart that shows that in the wet season in 1977 there were 20 portulaca seeds, in the dry season in 1977 there were none, and then it increased in the wet season of 1978 and went back up to 380 seeds.”
Evan:
“After I finish reading, I’m going to quickly explain a little bit about the chart we made. What we did next was, we circled all of the finches in both groups: the overweight group and the underweight group that survived. We determined that approximately 61 percent, or 14 out of 23, overweight finches survived the drought, while only 40 percent, or 9 out of 23, underweight finches survived the drought. Also, we noticed that the overweight finches tended to be male, and the underweight finches tended to be female.”
Nelly:
“Here are the groups; we circled the overweight ones, 14 that are circled, and these are all male. And these are all female, there’s 9 circled, and they are underweight.”
We can see the claim-evidence-reasoning framework in Leona’s portion of the presentation. As she explains, the group claims that rainfall caused the finch population decline. They provide a record of annual rainfall as evidence of that claim. And they continue by reasoning that plants require rainfall to thrive and that finches require plants as a food source for their survival. At this point in the investigation, Leona and her peers have not yet hit on the most strongly supported
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explanation for the finch population decline. However, the unit is not yet complete, and they and their classmates have developed an informed scientific way of working on, representing, and analyzing the scientific problem. As they continue to examine the data and build their scientific skills, they are well prepared to continue to learn from the investigation.
Scripting Student Roles
Another way that teachers can structure and focus students’ thinking while they engage in scientific investigations is to define and assign particular roles for students to play during portions of the investigation. When scientists meet to discuss their work and exchange ideas, they work in a milieu of shared beliefs and goals that regulate participation. They ask questions of one another, critique ideas, and hold each other accountable according to a set of agreed on, but typically unspoken, cultural conventions. Classroom communities rely on a similar set of beliefs, goals, and modes of participation in order to learn from scientific investigations. However, without extensive scientific training and experience in scientific communities, students need more explicit guidance and structuring to interact in ways that are scientifically productive and support their learning from investigations.
The scientific community reaches consensus by proposing and arguing about ideas through both written and verbal communication. This allows scientists a means by which to test their ideas with other scientists, who in turn provide them with feedback. In this way, the scientific community reaches a consensual understanding of how some aspects of the natural world work. A very similar practice takes place in effective science classrooms. Students ask questions, talk and write about problems, argue about models, and eventually come to a more nuanced and scientifically accepted understanding of natural phenomena. This kind of interaction, which is both social and cognitive, not only supports learning but also communicates how scientific knowledge is created.
As we discussed in Chapter 5, talk in the classroom can be academically productive in a general way and also in a way specific to science and scientific ideas and practices. The learning that results from hands-on science investigations in particular is dramatically improved when students present their ideas and arguments to their peers. In these instances, verbal communication among students is conducive to learning in general, but it also gives them experience with a uniquely
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science-oriented practice. For example, when students debate the value of a given scientific observation, this is analogous to what scientists in the real world do regularly. Yet most students have very little experience talking and thinking with their peers in the manner in which they are expected to during investigations. In fact, typical classroom experiences suggest a different dynamic—one in which textbooks and teachers are consulted for answers, rather than peers and data. Argumentation among students is rarely a sanctioned activity and is often experienced as acrimonious.
To help students learn appropriate ways of interacting during science investigations, educators have developed methods for helping them acquire new social roles and collectively building norms for interaction in ways that emulate the interactions of scientists. Educators can establish such norms by intentionally mirroring the social interaction model of questioning, listening, reflecting, and responding that scientists use in their exchanges with each other, as well as by assigning roles based on basic elements of this interaction. This approach has its roots in the reciprocal teaching approach to reading comprehension, which makes the process of comprehension explicit for learners.3 In reciprocal teaching of reading comprehension, teachers model the important elements of comprehension, such as predicting, summarizing, and questioning. Students then begin to take on the individual elements of the task. The task is essentially distributed among students, who share responsibility for its completion.
In the following case study, we look closely at a fifth-grade classroom in which learners are taught and assigned particular roles to play during an investigation. These roles are designed to emulate a range of intellectual and social practices that would seem more or less natural to the seasoned scientist. Note that in this case study the word “theory” is used to refer to students’ explanations rather than to formal scientific theories, such as evolution or plate tectonics.
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Science Class DIFFERENTIATING MASS AND DENSITY4
For the past month, Clarence Wilson, a fifth-grade teacher in a public school in the South Bronx, has been working with colleagues to develop a unit on mass and density. The unit combines exploration of the real-world phenomena related to sinking and floating with a conceptual model of density that was developed and implemented on a computer. They used a software program called Modeling with Dots, which introduced the students to a “dots-and-boxes” model of density (see Figure 7-1).
According to the model, each box represents a standard unit of volume (a size unit, or su), while each dot represented a mass unit (mu). The number of dots per box represented the density (mu/su). Thus, both of the objects shown were the same size: 8 boxes, or 8 su. The object on the left weighed 24 mass units, while the object on the right, at 40 mass units, was heavier. The density of the object on the right was greater (5 mu/su versus 3 mu/su).
Using another type of software called Archimedes, the students were able to perform simulated sinking and floating experiments, using the dots-and-boxes model of density (see Figure 7-2).
In carrying out simulated experiments such as these, Mr. Wilson’s students were free to specify the material they wanted the object and liquid to be made of, and they could then gather data from their experiments. The size of the objects was held constant in these simulations to help students focus on density as the variable. Students were challenged to discover the rule the computer used to determine whether the object would float or sink in a given liquid—a rule, consistent with reality, that was based on the relative densities of the object and the liquid.
In Figure 7-2, the object floats. The relative densities of the material to the liquid are 1:3, and one-third of the object sinks into the liquid.
The unit was intended to last for about 15 classroom sessions. The students engaged in some preliminary baseline activities that involved making predictions about 16 everyday objects, including a plastic spoon, an apple, and a piece of graphite.
FIGURE 7-1 Two objects represented by the grid-and-dots model with data display.
FIGURE 7-2 Grid-and-dots representation of an object floating in a liquid with data display.
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They predicted whether the objects would sink or float, shared their predictions and rationale, tested their predictions, recorded the results, and wrote reports that they shared with the class.
The students were assigned rotating procedural roles, such as reporter, scribe, and poster designer. Working in small groups, they moved through a series of stations in which they were asked to order a set of objects, first by mass and then by volume, make predictions about sinking or floating, test their predictions, record the results, and prepare a report for the class. The objects used in the different stations were large and small cylinders, large and small cubes, and a set of spheres made of wood, Lucite, recycled plastic, and aluminum. A different subset of these items was used at each different station.
Following this period of exploration, predicting, and theorizing, the students were introduced to the dots-and-boxes model of mass, volume, and density. They worked on computers to explore and then apply a dots-and-boxes model of density to several different objects, some real and some imagined. They then revisited their earlier work, using the dots-and-boxes model, to explain their sinking and floating results with real objects. Finally, they applied the model (on and off the computer) in exploring thermal expansion—why it is that heated alcohol takes up more space but weighs the same and has decreased density. They also explored why certain objects sank in hot water but floated in cold water.
At the beginning of the investigation, Mr. Wilson decided to try something new—assigning roles for student audience members whenever a student group presented its findings. He hoped that this would help promote productive discussion and participation during student reports. This presentation time often had become more of a conversation between the presenting group members and Mr. Wilson, rather than involving the whole class as intended.
The students in the audience were assigned, on a rotating basis, one of three audience roles: checking predictions and theories, checking summaries of results, and assessing the relationship among predictions, theories, and results. These three roles were designed to help give guidance to the students as they explored, through talk, three important intellectual practices in science: predicting and theorizing, summarizing results, and relating predictions and theories to results (sometimes referred to as coordinating theory and evidence).
STUDENT AUDIENCE
ROLES
INTELLECTUAL PRACTICES
IN SCIENCE
1.
Checking predictions and theories
Predicting and theorizing
2.
Checking summaries of results
Summarizing results
3.
Assessing the relation between predictions, theories, and results
Relating predictions and theories to results
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Mr. Wilson suspected that playing audience roles effectively would be challenging for his students, so he created several strategies for providing support. After introducing the roles, the class made a “question chart” that provided appropriate sample questions for each of the student audience roles. For the first role, checking predictions and theories, the questions on the chart read:
“What were some of your predictions?”
“Can you support your prediction with a theory?”
“Is your theory intelligible, plausible, and fruitful?”
Intelligibility, plausibility, and fruitfulness were terms that Mr. Wilson had been working on with his students all year.
For the second role, checking summaries of results, the student might ask:
“I’m not completely clear on what you found. Can you explain your evidence more clearly?”
For the third role, relating predictions, theories, and results, the questions read:
“Did you find what you originally predicted?”
“Did your results support your theory?”
“What evidence do you have that supports or challenges your theory?”
At the beginning of the unit, the students relied heavily on the question chart in performing their audience roles. They also had a difficult time, at first, distinguishing between predictions and theories. To address this, Mr. Wilson created a public “theory chart” that kept track of the different theories posed over time, with periodic review of theories occurring when students decided that some theories could be ruled out on the basis of the results from different groups.
The point of the theory chart was to reinforce the notion that science involves a process of revising thinking over time as new evidence arises. Mr. Wilson had decided that this theory chart would also help him challenge the prevalent idea among his students (and many others) that the object of doing science is to “get the right answer.” The theory chart helped make public the way in which the students’ collective thinking was changing over time. What follows is an excerpt from one of Mr. Wilson’s classes in which students use audience roles effectively.
Mr. Wilson: “Does anybody have a theory about the wood? For instance, why the wood floats? Why did you predict that the wood would float?”
Deana: “Because I’ve seen it float.”
Mr. Wilson: “So are you saying that just having seen something do something before is a reason, an explanation of why something would sink or float?”
Deana: “I think it is.”
Mr. Wilson: “You think it is? Can you say more about that?”
Deana: “Because if you’ve seen it before, then it’s a theory.”
Jody: “Wait, but didn’t we sort of decide that our experience is a good way of helping us make predictions, but it doesn’t explain why something happens?” [Christina waves her hand.]
Mr. Wilson: “Christina, do you have something to add?”
Christina: “Well, I sort of disagree with Deana, because a theory’s kind of different from a
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prediction. A theory is why something happened. It’s not just a guess or a prediction.”
Caleb: “I know what a theory is. A theory is like ‘all wood floats.’ That means all wood has to float or else your theory is wrong.”
Mr. Wilson: “Okay, so let me see if I’ve got what you’re saying. You’re saying that ‘all wood floats’ is a theory?”
Caleb: “Yep, a theory that’s been proven right.”
Mr. Wilson: “Does that tell me why wood floats though?”
Caleb: “Uh, not really.”
Mr. Wilson: “Okay, so can you give me an example? Let’s take wood. Some of us have seen in our experiments that wood floats. We have evidence that wood floats. But why does wood float? What makes it float? Can you give us a theory?”
Caleb: “My theory is that you can trap air underneath the wood.”
[Mr. Wilson notes Caleb’s theory on the theory chart.]
Elinor: “Your theory isn’t really [she looks at the question chart] intelligible to me. I don’t completely get what you mean by ‘wood traps air underneath it.’ [She looks at the question chart again.] Actually, it’s not really plausible to me either. I mean how would wood trap air underneath it? It’s not like a cup or anything, so how would wood do that? Do you have any evidence to support that theory? Did you see air bubbles? Or did you just come up with that theory from your mind?”
Caleb: [Smiling] “I just sort of flashed on it. But I like it. I mean it might have something to do with air.”
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This is an example of how teachers can intentionally structure student roles to focus student thinking and discussion on meaningful aspects of scientific investigation. Over a series of lessons these students practiced taking “roles” and learned to understand them in two ways. Initially, they learned to play procedural roles, which provided a framework for getting their group work done. (It is important to note that these were generic roles and not tied to specific scientific practices.) However, in addition to structuring their group tasks in a productive manner, the procedural roles gave the students some experience in playing assigned roles and engaging in interdependent tasks. Later, the students were assigned one of three audience roles. On a rotating basis, students would listen to their peers present and ask questions in order to check predictions and theories, check summaries of results, and assess the relation between predictions, theories, and results. In this case, the students played scientific roles. The science-specific audience roles were further defined—and students’ efforts to enact them aided—by a public display identifying examples of appropriate role-specific questions.
In the case of Mr. Wilson’s class, we saw students playing these roles in the context of a presentation. Christina pushed Deana to add an explanation to her prediction (Role 1, checking predictions and theories). Later, as Caleb asserted that “all wood floats,” Elinor consulted the chart and found language to appropriately challenge his assertion, which she saw as implausible. With the support of a teacher who listens to their ideas and peers who understand how to play meaningful roles in scientific discussion, the students successfully work on clarifying, supporting, and refining their ideas.
Scripting roles and framing science in an explanatory framework are but two of many ways in which creative teachers can intentionally and explicitly teach and support students to enact and make meaning of scientific investigations. We’ve chosen to discuss these particular strategies because they’ve been studied more extensively than other approaches and suggest promising results. Other ways teachers may make particular talk moves explicit include posting “talk stems,” such as, “I agree with X when he says Y, because [cite evidence]” or “I’d like to ask X to explain his thinking [evidence, model, theory, etc.] in more detail because I didn’t completely understand it.” They may also use methods such as position-driven discussions, in which students take particular positions (e.g., competing explanations for an observed phenomenon) and make a case for their position and build on peers’ challenges to their position, all before a demonstration is run and an outcome determined. There are many ways to invite students to engage in scientific discourse as legitimate participants, even before they have become totally competent at scientific investigation.
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Science Class LOOKING AT OUR SCIENTIFIC THINKING
Scientific investigations can take place over months and years in the K-8 grades, and when they are effective they can result in dramatic changes in the ways that students think about the topics they are studying, about their own thinking and learning, and about the enterprise of science. By actually looking at how their own thinking about a phenomenon has changed and developed, students see learning in action. In other words, they come to understand what it actually means to learn something—an understanding that is called for in Strand 3.
Like much of science learning, this kind of understanding will not evolve without intentional support from teachers and instructional materials. Reflecting on one’s own scientific knowledge is critical to the enterprise of science and science learning. Scientists integrate new knowledge gained through investigations only when that knowledge is examined in relation to what they already know, tentatively believe, or previously doubted. Children, like scientists, must learn to examine the history of their own thinking and revise it if necessary, in light of subsequent investigations.
To examine how effective teachers can teach students to reflect on their changing knowledge in this way, we visit the classroom of Sister Mary Gertrude Hennessey, a science teacher for grades 1-6 in a small, rural elementary school.
Sr. Hennessey understands that in order to reflect on knowledge over time, children require extended opportunities to work on critical scientific concepts. She systematically focuses her lessons on core ideas built cumulatively across the grades. She enables her students to think deeply about knowledge in two important ways: she guides them in thinking and talking about how the scientific community structures and develops knowledge, and she helps her students think deeply about their own thinking, or how to be “metacognitive.”
Research has shown that Sr. Hennessey’s sixth-grade students have a much better understanding of the nature of science than sixth graders from a comparable school. The table below shows the way both her role and her students’ roles change from first grade through sixth grade.
Here’s a look at Sr. Hennessey and her students in action:5
During a classroom demonstration in Sr. Hennessey’s first-grade classroom, a large, transparent container of water is placed on an overhead projector. Students are asked to predict what they think will happen when various objects are placed in the water. The objects in question are two stones—a small (2-centimeter diameter) granite stone, and a large (10-centimeter diameter) pumice stone. The students did not have the opportunity to handle the stones prior to the demonstration.
One student, Brianna, is called on to explain her predictions.
Sr. Hennessey: “Would anyone like to predict what he or she thinks will happen to these stones? Yes, Brianna?”
Brianna: “I think both stones will sink, because I know stones sink. I’ve seen lots of stones sink, and every time I throw a stone into the water, it always sinks.”
Sr. Hennessey: “You look like you want to say something else.”
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INCREASINGLY SOPHISTICATED METACOGNITION
FROM GRADES 1 THROUGH 66
GRADE
STUDENTS’ ROLE
TEACHER’S ROLE
1
Explicitly state their own views about the topic under consideration
Begin to consider the reasoning used to support their views
Begin to differentiate what they think from why they think it
Finds a variety of ways in which students can externally represent their thinking about the topic
Provides many experiences for students to begin to articulate the reasoning used to support ideas/beliefs
2
Begin to address the necessity of understanding other (usually peer) positions before they can discuss or comment on those positions
Toward the end of the year, begin to recognize inconsistency in the thoughts of others but not necessarily in their own thinking
Continues to provide an educational environment in which students can safely express their thoughts without reproaches from others
Introduces concept of consistency of thinking
Models consistent and inconsistent thinking (students can readily point out when teacher is being inconsistent)
3
Explore the idea that thoughts have consequences and that what one thinks may influence what one chooses to see
Begin to differentiate understanding what a peer is saying from believing what a peer is saying
Begin to comment on how their current ideas have changed from past ideas and to consider that current ideas may also need to be revised over time
Fosters metacognitive discourse among learners in order to illuminate students’ internal representations
Provides lots of examples from their personal work (which is saved from year to year) of student ideas
4-6
Begin to consider the implications and limitations of their personal thinking
Begin to look for ways of revising their personal thinking
Begin to evaluate their own/others’ thinking in terms of intelligibility, plausibility, and fruitfulness of ideas
Continue to articulate criteria for acceptance of ideas (i.e., consistency and generalizability)
Continue to employ physical representations of their thinking
Begin to employ analogies and metaphors, discuss their explicit use, and differentiate physical models from conceptual models
Articulate and defend ideas about “what learning should be like”
Provides historical examples of very important people changing their views and explanations over time
Begins to use students’ external representations of their thinking as a way of evaluating their ideas/beliefs (in terms of intelligibility, plausibility, and fruitfulness) in order to (a) create, when necessary, dissatisfaction in the mind of the learner to facilitate conceptual exchange or (b) look for ways of promoting conceptual change in the mind of the learner
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Brianna: “The water can’t hold up stones like it holds up boats, so I know the stones will sink.”
Sr. Hennessey: “You sound so sure, let me try another object.”
Brianna: “No, you have to throw it in, you have to test my idea first.”
[Sr. Hennessey places a small stone in the tank; it sinks.]
Brianna: “See, I told you it would sink.”
[Sr. Hennessey puts aside a larger stone and picks up another object.]
Brianna: “No, you have to test the big one, too, because if the little one sunk, the big one’s going to sink, too.”
[Sr. Hennessey places the larger stone in the tank and it floats.]
Brianna: “No! No!” [Brianna shakes her head.] “That doesn‘t go with my mind. That just doesn’t go with my mind.”
During the activity described above, Brianna is involved in a form of introspection in which she is processing and interpreting both past and present experience. For example, when Brianna says, “I think both stones will sink…. I’ve seen lots of stones sink, and every time I throw a stone in the water … it always sinks,” she reveals her current thinking about how that particular stone will behave in the water, based on her past experience with how stones have behaved in water.
As the discussion continues, Brianna reveals her beliefs about the nature of water. She uses her beliefs about water to support her current beliefs about stones. For example, she says, “The water can’t hold up stones like it holds up boats. I know the stones will sink.”
Brianna also insists on two separate occasions that Sr. Hennessey test her prediction by saying, “You have to test my ideas first,” and “You have to test the big one, too, because if the little one sunk, the big one’s going to sink, too.” It is important to note that Brianna asks her teacher to test her prediction as opposed to asking her merely to test what happens with the stone; Brianna is consciously aware that understanding her own thinking is the object of the demonstration.
Brianna’s reaction to having the larger stone float indicates that she is aware that the outcome is anomalous, and that this anomaly is inconsistent with her current view of both water and stones. “No! No!” she says. “That doesn’t go with my mind.” Her comment also shows that she is thinking about her own scientific thinking; she is being metacognitive.
The level of thinking about scientific thinking grows more sophisticated over time. Here’s another scenario involving Sr. Hennessey and one of her sixth-grade students.
Jill wrote an essay as part of the assessment process in her physics class. Her assigned task was to focus on “the element of change” in her thinking. The following questions were posed:
Do you think your ideas about force or forces acting on various objects have changed?
If so, in what way have your ideas changed? Why do you think your ideas have changed?
Here’s what Jill wrote:
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In the past I thought for instance the BOOK ON THE TABLE had only 1 force, and that force was gravity. I couldn’t see that something that wasn’t living could push back. I thought that this push back force wasn’t a real force but just an in the way force or an outside influence on the book.
However, my ideas have changed since the beginning of this year. Sr. Hennessey helped me to see the difference between the macroscopic level and the microscopic level. That was last year. But I never really thought about the difference very much.
This year, I began to think about the book on the table differently than [last school year] I was thinking on the macroscopic level and not on the microscopic level. This year I wasn’t looking at the table from the same perspective as last year. Last year I was looking at living beings as the important focus and now I am looking at the molecules as being the important focus. When I finally got my thoughts worked out, I could see things from a different perspective. I found out that I had no trouble thinking about two balanced forces instead of just gravity working on the book. It took me a whole YEAR to figure this concept out!!! Now I know it was worth THE YEAR to figure it out because now I can see balanced forces everywhere!
Balanced forces are needed to produce constant velocity. The book on the table has a velocity of zero; that means it has a steady pace of zero. Why, Sr. Hennessey asked, did my ideas change? I think my ideas changed because I have expanded my mind to more complicated ideas! Like molecules in a table can have an effect on a book, that balanced forces and unbalanced forces are a better way of explaining the cause of motion, and that constant velocity and changing velocity are important things to look at when describing motion.
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In her essay, Jill was able to examine both her past and current thinking. Moreover, she acknowledged that the construction of her thinking took a significant amount of time. The essay also reveals Jill’s belief about the nature of molecules (they can cause an effect) and her belief about the nature of an explanation (some explanations are better and are more important than others). In the first sentence, Jill merely reveals her past understanding of the forces acting on a book on a table. In the next sentences, she reveals her beliefs about the nature of living and nonliving objects and to some extent the nature of forces. Jill explicitly states that she was aware that her ideas had changed over time, and she offered a causal explanation for the change in her thinking. She acknowledges that she was aware of a shift in the focus of her thinking as well as a change in her thinking. Jill illustrates that she can generalize and apply her current understanding to new situations.
Jill also displays an impressive understanding of what physicists call kinetics, a set of concepts dealing with the action of forces producing or changing the motion of a body. This understanding is critical. Students may be able to question and monitor their ideas, but if their knowledge is not thorough and well structured enough to evaluate those ideas, it won’t do them any good. Metacognition, in and of itself, is not helpful without good cognition to be “meta” or reflective about.
What’s notable in Sr. Hennessey’s teaching is a strategic combination of support for students to think about the nature of scientific thinking (their own and others) linked to rigorous investigations that produce deep learning of scientific concepts.
Examples such as these shed light on the nature and range of students’ abilities to think about scientific knowledge, how it is constructed, and how complex and certain it is. These abilities are not all or nothing; rather, they exist on a continuum of engagement and elaboration: Brianna is a beginner to the process, whereas Jill demonstrates a high level of engagement in thinking about scientific thinking.
How, one might ask, did Sr. Hennessey accomplish such remarkable results? What was it about her teaching and her classroom environment that contributed to the tremendous growth in her students’ understanding of how knowledge is constructed in science? Here are some of the methods she uses. Notice all the different ways that talking about thinking and making thinking public play a role.
As Sr. Hennessey makes clear in her classroom, science is not only a body of knowledge but also a way of knowing. All science education practitioners, students, teachers, and even parents need to understand the nature and structure of scientific knowledge and the processes by which it is developed, not just the body of knowledge produced by science. They need to know how we know and why
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we believe scientific knowledge, not just what we know.
In science classrooms that include a strong component of metacognition, activities are introduced to make students aware of their initial ideas and to demonstrate that a conceptual problem may need to be solved. A variety of techniques may be useful in this regard. Students may be asked to make predictions about an event and give reasons for those predictions. Class discussion of the range of student predictions can emphasize alternative ways of thinking about a phenomenon, which can highlight the conceptual element of the analysis. In addition, gathering data that expose students to unexpected discrepancies or posing challenging problems that students may not immediately solve are ways of prompting students to stop and think, stepping outside their normal conceptual framework in order to understand what is happening.
Regular time for reflection, note taking, or public chart making to track ideas as they change over time is another critical component of metacognition. Researchers have documented that children often repeat experiments or interpret current results without connecting those results to prior hypotheses. Students need regular opportunities to reflect on science. Reflection helps students monitor their own understanding and track the progress of their investigations. It also helps them identify problems with their current plans, rethink plans, and keep track of pending goals.
Strategies for Teaching How to Construct Scientific Knowledge
FOCUS
Teaching for conceptual change
making students aware of their initial ideas
encouraging students to engage in metacognitive discourse about ideas
employing bridging analogies and anchors to help them consider and manipulate ideas
encouraging them to apply new understandings in different contexts
providing time for students to discuss the nature of learning and the nature of science
Promoting metacognitive understanding
Engaging students with deep domain-specific core concepts
PEDAGOGICAL PRACTICES
Helping students understand, test, and revise ideas
Establishing a classroom community that negotiates meaning and builds knowledge
Increasing students’ responsibility for directing important aspects of their own inquiry
STUDENT ROLES
Taking responsibility for representing ideas
Working to develop ideas
Monitoring the status of ideas
Considering the reasoning underlying specific beliefs
Deciding on ways to test specific beliefs
Assessing the consistency among ideas
Examining how well these ideas extend to new situations
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Thus, multiple approaches are needed in order for students to develop the ability to think about scientific thinking.
Classroom investigations can be an exciting way for students to develop a strong grasp of science content, the practices of scientific work, and the nature of science itself. However, investigations in current practice are typically not well suited to support student learning.
An effective science education system must reflect a rich, practice-based notion of science. This means rethinking what counts as science in order to better incorporate the strands of science learning. Investigations need not and should not be sequentially scripted, superficial experiences with predetermined outcomes, nor should they be chaotic, unstructured explorations that yield little in the way of real understanding. Effective investigations should be organized, structured activities that guide students in using scientific methods to work on meaningful problems.
Investigations that support student learning require teachers who understand how scientific problems evolve, and teachers themselves will need to have firsthand experiences akin to those they create for their students. Schools, universities, foundations, science centers, museums, and government agencies must find ways for teachers to have these experiences, building their knowledge and comfort with science practice in order to create an effective environment for student learning.
For Further Reading
Herrenkohl, L.R., and Guerra, M.R. (1998). Participant structures, scientific discourse, and student engagement in fourth grade. Cognition and Instruction, 16(4), 431-473.
McNeill, K.L., Lizotte, D.J., Krajcik, J., and Marx, R.W. (2006). Supporting students’ construction of scientific explanations by fading scaffolds in instructional materials. Journal of the Learning Sciences, 15(2), 153-191.
National Research Council. (2007). Teaching science as practice. Chapter 9 in Committee on Science Learning, Kindergarten Through Eighth Grade, Taking science to school: Learning and teaching science in grades K-8 (pp. 251-295). R.A. Duschl, H.A. Schweingruber, and A.W. Shouse (Eds.). Center for Education, Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.