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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, studentsâ understanding of science can flourish. Supporting student learning in regard to scientific investigations requires delib- erate and consistent instructional efforts. Research shows that simply âdoingâ 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 strandsâlearning sci- entific explanations, generating scientific evidence, reflecting on scientific knowledge, and participating in the social processes of scienceârequires intentional, sustained instruction and support. In this chapter, we focus on the kind of support that teach- ers can provide students to enable them to learn from their own scientific investiga- tions. We examine several practices that effective teachers, in collaboration with researchers, have developed to help students do science in a âminds onâ 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 mean- ingful both from the standpoint of the discipline and from the standpoint of the 127
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 prob- lem as meaningful, there is little chance that they will engage in the range of pro- ductive 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 earthâs surface unless disturbed? Why are some spe- cies 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 com- munity 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 gainedâpractically or intellectu- ally or bothâfrom 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 studentsâ 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 128 Ready, Set, SCIENCE!
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 ecosystemsâthat is, show- ing 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 stu- dents first recognize that the motion of light is critical to understanding how tele- scopes, eyes, and cameras function. Subsequent lessons on such topics as describ- ing 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 investiga- tion, 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 prob- lems, 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 impor- tance of reflecting on oneâs own scientific knowledge over the course of an investi- gation and the role of peers in building scientific arguments. A more productive approach is to intentionally build the appropriate sci- entific knowledge and skills âjust in time,â 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 Learning from Science Investigations 129
access to some basic concepts in order to see a problem and investigation as mean- ingful. 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 ana- lyzing 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 theyâve learned in light of previous observations. Like the problems themselves, these and other skills need to be made meaningful to stu- dents, and presenting them in the context of a problem to which they can be read- ily 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 studentsâ knowledge and skill over time so that they arrive at each phase in an investigation prepared to engage in the nec- essary work. âStruggle for Survivalâ is a six- to seven-week classroom science investi- gation 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 con- cepts 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 islandâs species at vari- ous 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 stu- dentsâ reasoning about core concepts. The students are presented with a prob- lem at the beginning of the unitâthe 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 studentsâ 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 130 Ready, Set, SCIENCE!
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 investiga- tion. Although from the very beginning students are presented with the challenge of explaining a shift in finch population, they do not dive immediately into col- lecting 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, stu- dents explore the data set, generate explanations for observed patterns of change in the finch populations, and critique Sequencing a Unit on Natural Selection the explanations of their classmates. Four Phases of Learning In the fourth phase (six classes), student Phase 1 General Staging Activities teams prepare reports, present findings, Determine what students know, provide background and analyze key points of agreement knowledge, build student motivation (10 classes). and disagreement across reports. Phase 2 Background for Investigations Carefully sequenced experiences Gather information, generate initial hypotheses, such as these provide a road map for work with small data set (five classes). students, and they build just-in-time Phase 3 Software Investigations skills and knowledge that allow them Investigate data, generate and critique explanations to work through complex problems for observations (10 classes). for which their knowledge and skill have immediate application. Students Phase 4 Presenting and Discussing Findings Prepare reports, present findings, analyze key points experience important elements of sci- (six classes). entific 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 ques- tion 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 argu- ments using scientific language conventions. Learning from Science Investigations 131
Constructing and Defending Explanations The science curriculum in most school systems focuses narrowly on âfinal form scienceââthe collection of scientific findings that populate textbooks. When students are given opportunities to âdoâ science, these experiences are often pre- sented as experiments with predetermined steps and findings. In other instances, science investigations take the form of âactivity maniaâ in which students com- plete 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 prob- lems. Rather, they are structured and regulated by the teacher, who plays an active role in the investigative experi- ence. 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 studentsâ thinking about sci- ence 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 studentsâ 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- 132 Ready, Set, SCIENCE!
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: â¢ Claim: What happened, and why did it happen? â¢ Evidence: What information or data support the claim? â¢ 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 under- standing 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 sup- ported 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: âAgain, 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. Iâm Evan, this is Leona, and this is Nelly. Here we go.â Leona: [Reading from a poster] âWe have a few theories. In conclud- ing our research concerning the study of finches on the island, our focus is to find out why the population of finches on that Learning from Science Investigations 133
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 por- tulaca 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.â Evan: âAfter I finish reading, Iâm 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 approxi- mately 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 over- weight finches tended to be male, and the underweight finches tended to be female.â Nelly: âHere are the groups; we circled the overweight ones, 14 that are circled, and these are all male. And these are all female, thereâs 9 circled, and they are underweight.â We can see the claim-evidence-reasoning framework in Leonaâs 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 134 Ready, Set, SCIENCE!
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 work- ing on, representing, and analyzing the scientific problem. As they continue to examine the data and build their scientific skills, they are well prepared to con- tinue to learn from the investigation. Scripting Student Roles Another way that teachers can structure and focus studentsâ thinking while they engage in scientific investigations is to define and assign particular roles for stu- dents to play during portions of the investigation. When scientists meet to dis- cuss 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 typ- ically 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 under- standing 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 interac- tion, which is both social and cognitive, not only supports learning but also com- municates 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 argu- ments 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 Learning from Science Investigations 135
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 dynamicâone 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 experi- enced as acrimonious. To help students learn appropriate ways of interacting during science inves- tigations, 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 read- ing 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 stu- dents, 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 investi- gation. These roles are designed to emulate a range of intellectual and social prac- tices that would seem more or less natural to the seasoned scientist. Note that in this case study the word âtheoryâ is used to refer to studentsâ explanations rather than to formal scientific theories, such as evolution or plate tectonics. 136 Ready, Set, SCIENCE!
Science Class DIFFERENTIATING MASS AND DENSITY4 For the past month, Clarence Wilson, a fifth-grade and floating experiments, using the dots-and-boxes teacher in a public school in the South Bronx, has model of density (see Figure 7-2). been working with colleagues to develop a unit on In carrying out simulated experiments such as mass and density. The unit combines exploration of these, Mr. Wilsonâs students were free to specify the real-world phenomena related to sinking and the material they wanted the object and liquid to floating with a conceptual model of density that was be made of, and they could then gather data from developed and implemented on a computer. They their experiments. The size of the objects was held used a software program called Modeling with Dots, constant in these simulations to help students focus which introduced the students to a âdots-and-boxesâ on density as the variable. Students were challenged model of density (see Figure 7-1). to discover the rule the computer used to determine According to the model, each box represents a whether the object would float or sink in a given standard unit of volume (a size unit, or su), while liquidâa rule, consistent with reality, that was based each dot represented a mass unit (mu). The number on the relative densities of the object and the liquid. of dots per box represented the density (mu/su). In Figure 7-2, the object floats. The relative den- Thus, both of the objects shown were the same size: sities of the material to the liquid are 1:3, and one- 8 boxes, or 8 su. The object on the left weighed 24 third of the object sinks into the liquid. mass units, while the object on the right, at 40 mass The unit was intended to last for about 15 units, was heavier. The density of the object on the classroom sessions. The students engaged in some right was greater (5 mu/su versus 3 mu/su). preliminary baseline activities that involved making Using another type of software called Archimedes, predictions about 16 everyday objects, including the students were able to perform simulated sinking a plastic spoon, an apple, and a piece of graphite. 24 mass units 40 mass units Data 8 size units 8 size units 1/3 of object is in the liquid 3 mu/su 5 mu/su Object Liquid Mass Mass 12 mu 120 mu Size Size 12 su 40 su Density Density 1 mu/su 3 mu/su FIGURE 7-1 FIGURE 7-2 Two objects represented by the grid-and-dots model with Grid-and-dots representation of an object floating in a data display. liquid with data display. Learning from Science Investigations 137
They predicted whether the objects would sink or and off the computer) in exploring thermal expan- float, shared their predictions and rationale, tested sionâwhy it is that heated alcohol takes up more their predictions, recorded the results, and wrote space but weighs the same and has decreased density. reports that they shared with the class. They also explored why certain objects sank in hot The students were assigned rotating procedural water but floated in cold water. roles, such as reporter, scribe, and poster designer. At the beginning of the investigation, Mr. Working in small groups, they moved through Wilson decided to try something newâassigning a series of stations in which they were asked to roles for student audience members whenever a order a set of objects, first by mass and then by student group presented its findings. He hoped volume, make predictions about sinking or float- that this would help promote productive discussion ing, test their predictions, record the results, and and participation during student reports. This pre- prepare a report for the class. The objects used in sentation time often had become more of a con- the different stations were large and small cylin- versation between the presenting group members ders, large and small cubes, and a set of spheres and Mr. Wilson, rather than involving the whole made of wood, Lucite, recycled plastic, and alumi- class as intended. num. A different subset of these items was used at The students in the audience were assigned, on each different station. a rotating basis, one of three audience roles: check- Following this period of exploration, predicting, ing predictions and theories, checking summaries of and theorizing, the students were introduced to the results, and assessing the relationship among predic- dots-and-boxes model of mass, volume, and density. tions, theories, and results. These three roles were They worked on computers to explore and then apply designed to help give guidance to the students as a dots-and-boxes model of density to several differ- they explored, through talk, three important intel- ent objects, some real and some imagined. They then lectual practices in science: predicting and theoriz- revisited their earlier work, using the dots-and-boxes ing, summarizing results, and relating predictions model, to explain their sinking and floating results and theories to results (sometimes referred to as with real objects. Finally, they applied the model (on coordinating theory and evidence). STUDENT AUDIENCE INTELLECTUAL PRACTICES ROLES IN SCIENCE 1. Checking predictions and theories Predicting and theorizing 2. Checking summaries of results Summarizing results 3. Assessing the relation between Relating predictions and theories to results predictions, theories, and results 138 Ready, Set, SCIENCE!
Mr. Wilson suspected that playing audience roles The point of the theory chart was to reinforce effectively would be challenging for his students, so the notion that science involves a process of revis- he created several strategies for providing support. ing thinking over time as new evidence arises. Mr. After introducing the roles, the class made a âques- Wilson had decided that this theory chart would also tion chartâ that provided appropriate sample ques- help him challenge the prevalent idea among his tions for each of the student audience roles. For students (and many others) that the object of doing the first role, checking predictions and theories, the science is to âget the right answer.â The theory chart questions on the chart read: helped make public the way in which the studentsâ collective thinking was changing over time. What fol- âWhat were some of your predictions?â lows is an excerpt from one of Mr. Wilsonâs classes in âCan you support your prediction with a theory?â which students use audience roles effectively. âIs your theory intelligible, plausible, and fruitful?â Mr. Wilson: âDoes anybody have a theory about the wood? For instance, why the wood Intelligibility, plausibility, and fruitfulness were floats? Why did you predict that the wood terms that Mr. Wilson had been working on with his would float?â students all year. Deana: âBecause Iâve seen it float.â For the second role, checking summaries of results, the student might ask: Mr. Wilson: âSo are you saying that just hav- ing seen something do something before is âIâm not completely clear on what you found. Can a reason, an explanation of why something you explain your evidence more clearly?â would sink or float?â For the third role, relating predictions, theories, Deana: âI think it is.â and results, the questions read: Mr. Wilson: âYou think it is? Can you say âDid you find what you originally predicted?â more about that?â âDid your results support your theory?â Deana: âBecause if youâve seen it before, then itâs a theory.â âWhat evidence do you have that supports or challenges your theory?â Jody: âWait, but didnât we sort of decide that our experience is a good way of helping At the beginning of the unit, the students relied us make predictions, but it doesnât explain heavily on the question chart in performing their why something happens?â [Christina waves audience roles. They also had a difficult time, at first, her hand.] distinguishing between predictions and theories. To address this, Mr. Wilson created a public âtheory chartâ Mr. Wilson: âChristina, do you have some- that kept track of the different theories posed over thing to add?â time, with periodic review of theories occurring when Christina: âWell, I sort of disagree with Deana, students decided that some theories could be ruled out because a theoryâs kind of different from a on the basis of the results from different groups. Learning from Science Investigations 139
prediction. A theory is why something hap- Caleb: âMy theory is that you can trap air pened. Itâs not just a guess or a prediction.â underneath the wood.â Caleb: âI know what a theory is. A theory is [Mr. Wilson notes Calebâs theory on the theo- like âall wood floats.â That means all wood ry chart.] has to float or else your theory is wrong.â Elinor: âYour theory isnât really [she looks at Mr. Wilson: âOkay, so let me see if Iâve got the question chart] intelligible to me. I donât what youâre saying. Youâre saying that âall completely get what you mean by âwood wood floatsâ is a theory?â traps air underneath it.â [She looks at the question chart again.] Actually, itâs not really Caleb: âYep, a theory thatâs been proven plausible to me either. I mean how would right.â wood trap air underneath it? Itâs not like Mr. Wilson: âDoes that tell me why wood a cup or anything, so how would wood do floats though?â that? Do you have any evidence to support that theory? Did you see air bubbles? Or did Caleb: âUh, not really.â you just come up with that theory from your mind?â Mr. Wilson: âOkay, so can you give me an example? Letâs take wood. Some of us have Caleb: [Smiling] âI just sort of flashed on it. seen in our experiments that wood floats. But I like it. I mean it might have something We have evidence that wood floats. But why to do with air.â does wood float? What makes it float? Can you give us a theory?â 140 Ready, Set, SCIENCE!
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 ârolesâ and learned to understand them in two ways. Initially, they learned to play proce- dural 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 produc- tive 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 definedâand studentsâ efforts to enact them aidedâ by a public display identifying examples of appropriate role-specific questions. In the case of Mr. Wilsonâs 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 âall wood floats,â Elinor consulted the chart and found language to appropri- ately 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 meaning- ful roles in scientific discussion, the students successfully work on clarifying, sup- porting, 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 sup- port students to enact and make meaning of scientific investigations. Weâve chosen to discuss these particular strategies because theyâve been studied more extensively than other approaches and suggest promising results. Other ways teachers may make particular talk moves explicit include posting âtalk stems,â such as, âI agree with X when he says Y, because [cite evidence]â or âIâd like to ask X to explain his thinking [evidence, model, theory, etc.] in more detail because I didnât completely understand it.â They may also use methods such as position-driven discussions, in which stu- dents take particular positions (e.g., competing explanations for an observed phenom- enon) and make a case for their position and build on peersâ challenges to their posi- tion, 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. Learning from Science Investigations 141
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 somethingâan 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 oneâs 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 âmetacognitive.â Research has shown that Sr. Hennesseyâs 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 stu- dentsâ roles change from first grade through sixth grade. Hereâs a look at Sr. Hennessey and her students in One student, Brianna, is called on to explain her action:5 predictions. During a classroom demonstration in Sr. Sr. Hennessey: âWould anyone like to predict Hennesseyâs first-grade classroom, a large, transpar- what he or she thinks will happen to these ent container of water is placed on an overhead stones? Yes, Brianna?â projector. Students are asked to predict what they Brianna: âI think both stones will sink, think will happen when various objects are placed because I know stones sink. Iâve seen lots of in the water. The objects in question are two stones sink, and every time I throw a stone stonesâa small (2-centimeter diameter) granite into the water, it always sinks.â stone, and a large (10-centimeter diameter) pumice stone. The students did not have the opportunity Sr. Hennessey: âYou look like you want to say to handle the stones prior to the demonstration. something else.â 142 Ready, Set, SCIENCE!
INCREASINGLY SOPHISTICATED METACOGNITION FROM GRADES 1 THROUGH 6 6 GRADE STUDENTSâ ROLE TEACHERâS ROLE 1 â¢ Explicitly state their own views about the â¢ Finds a variety of ways in which students can topic under consideration externally represent their thinking about the topic â¢ Begin to consider the reasoning used to support their views â¢ Provides many experiences for students to begin to articulate the reasoning used to â¢ Begin to differentiate what they think from support ideas/beliefs why they think it 2 â¢ Begin to address the necessity of understand- â¢ Continues to provide an educational environ- ing other (usually peer) positions before they ment in which students can safely express their can discuss or comment on those positions thoughts without reproaches from others â¢ Toward the end of the year, begin to recog- â¢ Introduces concept of consistency of thinking nize inconsistency in the thoughts of others â¢ Models consistent and inconsistent thinking but not necessarily in their own thinking (students can readily point out when teacher is being inconsistent) 3 â¢ Explore the idea that thoughts have â¢ Fosters metacognitive discourse among learn- consequences and that what one thinks may ers in order to illuminate studentsâ internal influence what one chooses to see representations â¢ Begin to differentiate understanding what a â¢ Provides lots of examples from their personal peer is saying from believing what a peer is work (which is saved from year to year) of saying student ideas â¢ 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 4-6 â¢ Begin to consider the implications and â¢ Provides historical examples of very limitations of their personal thinking important people changing their views and explanations over time â¢ Begin to look for ways of revising their personal thinking â¢ Begins to use studentsâ external representa- tions of their thinking as a way of evaluating â¢ Begin to evaluate their own/othersâ thinking their ideas/beliefs (in terms of intelligibility, in terms of intelligibility, plausibility, and plausibility, and fruitfulness) in order to (a) fruitfulness of ideas create, when necessary, dissatisfaction in the â¢ Continue to articulate criteria for acceptance mind of the learner to facilitate conceptual of ideas (i.e., consistency and generalizability) exchange or (b) look for ways of promoting â¢ Continue to employ physical representations conceptual change in the mind of the learner of their thinking â¢ Begin to employ analogies and metaphors, discuss their explicit use, and differentiate physical models from conceptual models â¢ Articulate and defend ideas about âwhat learning should be likeâ Learning from Science Investigations 143
Brianna: âThe water canât hold up stones like it about stones. For example, she says, âThe water holds up boats, so I know the stones will sink.â canât hold up stones like it holds up boats. I know the stones will sink.â Sr. Hennessey: âYou sound so sure, let me try Brianna also insists on two separate occasions another object.â that Sr. Hennessey test her prediction by saying, Brianna: âNo, you have to throw it in, you âYou have to test my ideas first,â and âYou have to have to test my idea first.â test the big one, too, because if the little one sunk, the big oneâs going to sink, too.â It is important to [Sr. Hennessey places a small stone in the note that Brianna asks her teacher to test her predic- tank; it sinks.] tion as opposed to asking her merely to test what happens with the stone; Brianna is consciously aware Brianna: âSee, I told you it would sink.â that understanding her own thinking is the object of [Sr. Hennessey puts aside a larger stone and the demonstration. picks up another object.] Briannaâs reaction to having the larger stone float indicates that she is aware that the outcome Brianna: âNo, you have to test the big one, is anomalous, and that this anomaly is inconsistent too, because if the little one sunk, the big with her current view of both water and stones. oneâs going to sink, too.â âNo! No!â she says. âThat doesnât go with my [Sr. Hennessey places the larger stone in the mind.â Her comment also shows that she is think- tank and it floats.] ing about her own scientific thinking; she is being metacognitive. Brianna: âNo! No!â [Brianna shakes her The level of thinking about scientific thinking head.] âThat doesnât go with my mind. That grows more sophisticated over time. Hereâs another just doesnât go with my mind.â scenario involving Sr. Hennessey and one of her sixth-grade students. During the activity described above, Brianna is Jill wrote an essay as part of the assessment pro- involved in a form of introspection in which she cess in her physics class. Her assigned task was to is processing and interpreting both past and pres- focus on âthe element of changeâ in her thinking. ent experience. For example, when Brianna says, The following questions were posed: âI think both stones will sink. . . . Iâve seen lots of stones sink, and every time I throw a stone in the â¢ Do you think your ideas about force or forces water . . . it always sinks,â she reveals her current acting on various objects have changed? thinking about how that particular stone will behave in the water, based on her past experience with how â¢ If so, in what way have your ideas changed? stones have behaved in water. Why do you think your ideas have changed? As the discussion continues, Brianna reveals her Hereâs what Jill wrote: beliefs about the nature of water. She uses her beliefs about water to support her current beliefs 144 Ready, Set, SCIENCE!
In the past I thought for instance the BOOK ON THE TABLE had only 1 force, and that force was gravity. I couldnât see that something that wasnât living could push back. I thought that this push back force wasnât 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 wasnât looking at the table from the same per- spective as last year. Last year I was looking at living beings as the impor- tant 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 mol- ecules 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. Learning from Science Investigations 145
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 Jillâs 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 nonliv- ing 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 kinet- ics, 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 wonât do them any good. Metacognition, in and of itself, is not helpful without good cognition to be âmetaâ or reflective about. Whatâs notable in Sr. Hennesseyâs 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 studentsâ abili- ties 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 contin- uum 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 studentsâ understanding of how knowledge is constructed in science? Here are some of the methods she uses. Notice all the dif- ferent 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, stu- dents, 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 146 Ready, Set, SCIENCE!
Strategies for Teaching How to Construct we believe scientific knowledge, not just Scientific Knowledge what we know. FOCUS In science classrooms that include a strong component of metacognition, 1. Teaching for conceptual change activities are introduced to make students - making students aware of their initial ideas aware of their initial ideas and to demon- - encouraging students to engage in metacognitive strate that a conceptual problem may need discourse about ideas to be solved. A variety of techniques may - employing bridging analogies and anchors to help be useful in this regard. Students may be them consider and manipulate ideas asked to make predictions about an event - encouraging them to apply new understandings in and give reasons for those predictions. different contexts Class discussion of the range of student - providing time for students to discuss the nature of predictions can emphasize alternative ways learning and the nature of science of thinking about a phenomenon, which 2. Promoting metacognitive understanding can highlight the conceptual element of the analysis. In addition, gathering data 3. Engaging students with deep domain-specific core that expose students to unexpected dis- concepts crepancies or posing challenging problems PEDAGOGICAL PRACTICES that students may not immediately solve are ways of prompting students to stop â¢ Helping students understand, test, and revise ideas and think, stepping outside their normal â¢ Establishing a classroom community that negotiates conceptual framework in order to under- meaning and builds knowledge stand what is happening. Regular time for reflection, note tak- â¢ Increasing studentsâ responsibility for directing important aspects of their own inquiry ing, or public chart making to track ideas as they change over time is another critical STUDENT ROLES component of metacognition. Researchers â¢ Taking responsibility for representing ideas have documented that children often repeat experiments or interpret current results â¢ Working to develop ideas without connecting those results to prior â¢ Monitoring the status of ideas hypotheses. Students need regular oppor- tunities to reflect on science. Reflection â¢ Considering the reasoning underlying specific beliefs helps students monitor their own under- â¢ Deciding on ways to test specific beliefs standing and track the progress of their investigations. It also helps them identify â¢ Assessing the consistency among ideas problems with their current plans, rethink â¢ Examining how well these ideas extend to new situations plans, and keep track of pending goals. Learning from Science Investigations 147
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 first- hand 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 studentsâ 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. 148 Ready, Set, SCIENCE!