Model-Based Inquiry in Biology: Three-Dimensional Instructional Units for Grades 9-12

Introduction

What Is MBI and Why Is It Important?

Model-based inquiry (MBI) is a framework for designing units and engaging students in science learning experiences that is focused on the construction, critique, revision, and testing of models by groups of students in science classrooms as they seek to explain events that happen in the world. This focus on explaining events in the world is important for several reasons. First, it creates a space for students to participate more authentically in the knowledge production practices of the science disciplines (NRC 2012). Second, it creates a problem space in which students can learn to use their own ideas along with the disciplinary core ideas, crosscutting concepts, and practices of science to make sense of the world around them. Third, focusing on explaining events shifts the emphasis of classroom activity from We need to learn about this topic in order to do well in class to How will this help us figure out why or how something happens? Finally, and perhaps most importantly, explaining events creates a need to learn and helps students understand why science is useful. This framework, with its emphasis on explaining events through the development of models, provides a context for the work of students in the science classroom and a way for teachers to create learning experiences that are meaningful to students.

Most students in U.S. science classrooms have not had an opportunity to explain a real-world event. Instead, students are expected to learn about many different topics in science in an abstract manner. In many classrooms, a topic is chosen (e.g., natural selection), and then students are given several different learning experiences, such as lectures, labs, and other activities, to help them understand the topic. These experiences are intended to ensure that students develop adequate knowledge about the topic before they take a summative assessment.

In contrast to this more traditional approach, MBI learning experiences, organized in instructional units, are driven by a need to explain the events that happen in the world. These events are often described as anchoring phenomena because they serve as an anchor or foundation for a sequence of classroom activities and create a reason to learn specific core ideas, crosscutting concepts, and practices of science. Student ideas about the science around an anchoring phenomenon are the central focus of each instructional unit. These ideas are elicited early, and students keep track of them with public records and collaboratively negotiate with peers throughout the unit. An MBI instructional unit culminates with students writing individual evidence-based explanations of the anchoring phenomenon. (See Figure I.1 on page xviii for a comparison between traditional science units and MBI science units.) In sum, MBI experiences are about equitably engaging all learners in meaningful forms of participation in science classrooms in ways that value the resources (e.g., ideas, experiences, knowledge production practices) that learners bring to the learning environment, while also supporting the collaborative construction and critique of explanations with these resources.

Figure I.1. Comparisons Between Traditional and MBI Units

Where MBI Came From and Where It Is Going

In our previous collaborations over the years with preservice and inservice science teachers, we have come to appreciate the importance of modeling as a practice, both for students to work with their ideas and find connections between ideas and for teachers as the models provide insight into the ways students’ explanations are evolving. Additionally, we have come to see the practice of modeling as a knowledge-building practice that is inextricably linked to other practices, such as asking questions, arguing, investigating, and explaining. Put more succinctly, it really is not possible for students to engage in modeling without engaging in the other science practices. Having noted this in our work with teachers and students in classrooms, we have collaborated with teachers and other researchers over the past decade to identify, test, and refine productive ways of engaging students in the practice of modeling across instructional units. In the end, this book is the product of that work.

How We Designed These Units

The design of the units presented here was a highly collaborative effort between teacher educators and secondary science teachers who developed, tested, and refined the units over the course of a year. The group codesigned each unit and tested it out in classrooms at least three times before creating a final version. Practical tips from our collaborating teachers are included in the units to help make implementation in your classroom as smooth as possible.

How to Use This Book

The intended audience of the book is primarily practicing high school biology teachers. While the MBI units are written toward the Next Generation Science Standards (NGSS), we believe teachers in non-NGSS states will find them useful as well. The four units included here are not meant to provide an entire yearlong curriculum. We chose to focus each unit on one of the four life science disciplinary core ideas (DCIs) from the NGSS. No unit is sufficient to cover all the performance expectations for each DCI. You can see what is and what is not included in Appendix A. In a traditional yearlong high school biology course, the units described here could be expected to cover approximately half of the required curriculum. However, the four units are designed to cover the most important ideas in each DCI.

We want to make clear that teachers may choose to substitute certain labs or activities for tasks provided here. As long as the new tasks are targeted at the same important science ideas, then students will be able to use them just as well to apply their new understandings to their building explanations of the phenomena. The effectiveness of the MBI units is not necessarily in the specific tasks. Rather, it is the role of the anchoring phenomenon, the organization of the science ideas throughout the unit, and the intellectual work done during the four MBI stages (as described in Chapter 1) as students use their ideas and those presented through tasks to collaboratively construct their final evidence-based explanations of the phenomena at the heart of these units.

Organization of This Book

This book is primarily divided into two sections. In Section 1, Chapter 1 introduces MBI, and Chapter 2 provides in-depth discussions of the ideas framing MBI and the specific stages of MBI. Section 2 contains the four complete MBI biology units. Each unit has multiple components:

•The unit summary, which includes an overall description of the unit, a summary of the phenomenon anchoring the unit, a driving question, an example target explanation, and guides for how the unit tasks fit together to lead students to their final evidence-based explanations of the phenomenon.

•Stage summaries, which give specific descriptions of each of the four stages of the MBI process. These are placed at appropriate spots throughout the unit and are a reminder that the MBI unit is more than the tasks presented.

•The tasks, each of which consists of two components:

•Teacher Notes, which present information about the purpose of the task and explain what you need to do to guide students through it.

•A Student Handout, which provides students with the necessary information and space for responses to complete the task. The handouts can be photocopied and given to students at the beginning of the task.

The book concludes with three appendixes in Section 3:

•Appendix A contains standards alignment matrixes that can be used to assist with curriculum planning.

•Appendix B includes a peer-review guide that can be photocopied and given to students.

•Appendix C is a safety acknowledgment form that can also be photocopied and given to students.

Supplementary Materials

This book includes supplementary materials in the form of PowerPoint presentations, which are referenced in the appropriate places in the text. Several are step-by-step guides that lead you through the Eliciting Ideas About the Phenomenon stage for each unit; the others serve as templates that you can use with your class for the other stages and for model testing and revision. These materials can be accessed on the book’s Extras page at www.nsta.org/mbi-biology.

Safety

Doing science through hands-on, process- and inquiry-based activities and experiments helps foster the learning and understanding of science. However, to make for a safer experience, teachers and students must follow certain safety procedures based on legal safety standards and better professional safety practices. Tasks include relevant safety precautions that will help make a safer hands-on learning experience for you and your students. In some cases, eye protection and additional personal protective equipment (nonlatex aprons and vinyl or nitrile gloves) are required, based on potential safety hazards and resulting risks. Safety glasses or safety goggles must meet the ANSI Z87.1 D3 safety standard. For additional safety information, check out NSTA’s Safety in the Science Classroom at https://static.nsta.org/pdfs/SafetyInTheScienceClassroom.pdf.

Reference

National Research Council (NRC). 2012. A framework for K–12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Academies Press.

SECTION 1 Using Model-Based Inquiry

CHAPTER 1

Model-Based Inquiry

Stages of Model-Based Inquiry

Model-based inquiry (MBI) is based on a need to explain anchoring phenomena and to put student ideas and resources at the center of instruction. We believe that curriculum is necessary but not sufficient for great instruction. Curriculum provides the foundation for the important work that happens in your classroom. Layered over curriculum, however, is great instruction. As you’ll see, we have purposely designed the process to provide the space and resources for effective instruction within the units. These connections are made more explicit in Chapter 2. In short, we believe in instruction that promotes equitable science instruction and the construction of students’ identities in science. We see MBI as a way to transform science curricula and teaching practices to realize this vision.

MBI is broken up into four distinct stages (see Figure 1): (1) eliciting ideas about the phenomenon, (2) negotiating ideas and evidence through tasks, (3) building consensus, and (4) establishing credibility. These four stages are included in each MBI unit. Each stage consists of several activities and, as a result, will take two or more instructional days to complete. An MBI unit might be different from a traditional science unit and other instructional approaches that focus on the practice of modeling. Each stage is described in detail in the following sections.

Figure 1. The Four Stages of an MBI Unit

Stage 1: Eliciting Ideas About the Phenomenon

The first stage of MBI, eliciting ideas about the phenomenon (Figure 2), involves introducing the anchoring phenomenon and driving question; eliciting students’ ideas and experiences, which may help them begin to formulate explanations for the phenomenon; and developing initial models based on those ideas. This phase usually takes the entire first day and includes putting the students into groups of three or four that will work together throughout the unit.

Figure 2. Eliciting Ideas About the Phenomenon

We begin this stage by introducing the phenomenon in an engaging way, such as with stories, videos, demonstrations, or even short activities. The goal is to provide just enough information for students to begin to reason about the phenomenon, without providing too much of the explanation. While we are introducing the phenomenon, we ask questions to keep students engaged and make sure they are paying attention to the important aspects. The introduction ends with the driving question of the unit, which we have found helps focus their thinking on the development of a causal explanation for the phenomenon, or a why answer. We then get students into their groups and facilitate the first discussion to try to answer the driving question with just the resources they brought with them—the ideas, experiences, and cultural resources they have gained both in and outside of the classroom. These ideas may be fully formed, partially correct, or fully incorrect in terms of our canonical knowledge of science. However, we make it clear that all ideas are considered equally valid at this point in time, as we realize that these are the ideas that students put into play when they think about the phenomenon we have introduced. As described more fully in Chapter 2, it is these ideas, along with those we introduce through the tasks, that are at the heart of the sensemaking that students need to do to explain the phenomenon.

Once student groups have discussed their ideas, we facilitate a class discussion to compare and contrast the ideas generated by each group. As ideas are presented, they are put on our first public record, which we call the Initial Hypotheses List. We use this list throughout the unit to keep track of the changes in students’ thinking as they work toward a final evidence-based explanation for the anchoring phenomenon. We consider all ideas to be valid at this stage, before students use other resources to begin making sense of how or why something happens. The Initial Hypotheses List is also useful for the next task in this stage, initial model construction, especially since it offers students additional ideas beyond those they initially had either individually or in their small groups.

If students are not experienced with modeling, it is worth providing a brief introduction and example. Examples of modeling are included in the Eliciting Ideas About the Phenomenon PowerPoints for each unit, which can be downloaded from the book’s Extras page at www.nsta.org/mbi-biology. Once the class is ready to begin modeling, we give each group a sheet of 11 × 17 inch paper and ask the groups to each make a model of their initial hypothesis. Sometimes they choose their own original hypotheses, while other times they are influenced by their peers’ ideas and adopt one of them instead. As the groups work on constructing their models, you should walk around asking clarifying questions and pushing students to be as specific as possible. Once the models are ready, it is important to have students share ideas across them. There are a number of ways you might run these share-out sessions. We often collect and present the models on a document camera at the end of the first day. Groups can provide one- or two-sentence summaries of the initial hypotheses that they have represented in their models. We point out interesting ideas and ways in which they have represented these ideas. For example, we may call attention to the fact that a group labeled the arrows, which made the model more understandable, and that another group used a zoom-in window to show what was happening at a different scale. At the end of the first day and this first stage, we have elicited ideas across the class, and the groups’ initial hypotheses and models will act as a starting point for the rest of the unit.

Stage 2: Negotiating Ideas and Evidence Through Tasks

The goal of the second stage, negotiating ideas and evidence through tasks (Figure 3), is to support students’ ongoing changes in thinking by providing learning experiences that help coordinate their ideas, core ideas, and crosscutting concepts to build a scientific explanation of the anchoring phenomenon. This involves designing or adapting a number of data-based tasks, introducing core ideas and crosscutting concepts, and constructing and using public records such as a Summary Table to help keep track of what students have figured out, how they know what they know, what these ideas help them explain, and new questions they may have. Important in this stage are the revision and testing of students’ models. This stage makes up the majority of the unit, as the class works to develop explanations of the phenomenon through engagement in the practices of science. For each important idea, there is at least one task, and the steps shown in Figure 3 and described in this section are repeated for each task.

Figure 3. Negotiating Ideas and Evidence Through Tasks

Throughout this book, we prioritize a basic sequence of practices before, during, and after each task. These are flexible depending on your context, but we have found them to work well based on our goals of equity and using students’ ideas as resources for sensemaking. First, instead of relying on students to discover important science ideas from our tasks, we highlight these ideas before the task begins. This often happens with short, direct instruction in which we highlight an idea such as natural selection. Then the tasks engage students with data that link to these ideas as part of a sensemaking experience. We don’t see this as giving away the answer. Instead, it allows them more time to reason about the idea before ending the task by doing the intellectually challenging work of applying it to the phenomenon. The true intellectual work of a task is not just understanding the concept of natural selection, for example, but figuring out how to apply that concept to explain some event in the world, which in the task is the anchoring phenomenon.

While student groups are working on the task, we engage with each group and ask back pocket questions that are designed to stretch their thinking. This usually involves going to a group, listening in for a minute or two to understand how their conversation is progressing, and asking questions that press them to go further. We also focus on making sure each person in the group is able to share their ideas. As we finish, we ask a leaving question that encourages students to continue thinking about what they are doing after we have left for the next group. This process also allows us to monitor where groups are in their thinking so we know whom to call on for the most productive discussion after the task has finished.

After students have completed the task and put away the materials, we move to a whole-class discussion to make sense of the task as a class. This can occur in a number of different ways, depending on the nature of the task. For example, data from each group can be combined to begin to make sense of the foregrounded ideas. We use another public record, the Summary Table, after each task to wrap it up in two ways. First, it allows students to summarize what they learned from the task about the foregrounded ideas. Second, it prompts them to think about how their new ideas and understandings are related to the explanation of the phenomenon. We have found the conversations the class has while working to fill out the Summary Table are incredibly important but also very challenging. We have found ways to make filling out the table go more smoothly. For instance, we don’t use bullet points but instead write one or two complete sentences on the table. To make it easier to construct these sentences, we ask that groups first write their ideas in the section titled Some Useful Ideas From My Teacher, found near the end of the Student Handout, in one or two complete sentences as well. Then, as we elicit responses and compare and contrast them, they are already fully formed thoughts, making it easier for students to summarize them in full sentences on the Summary Table.

About halfway through the unit, students should go back to the initial models constructed on the first day and revise them based on what they have learned. This can be done in multiple ways. For instance, they can review their initial models and use sticky notes to flag anything that should change based on what they’ve learned as documented on the Summary Table. Alternatively, they can have discussions about what to change and then redraw their models. We make the choice between these options based on the amount of time we have for the model revision process. It is important, however, that students make decisions about revisions based on what fits with the evidence from the tasks and is consistent with the scientific ideas at play.

In the end, during this stage, students have built on their initial ideas elicited on the first day by engaging in data-based tasks, each designed around one or more central scientific ideas required for a complete scientific explanation of the phenomenon. Some of these ideas were introduced by students, and we introduced others. By keeping these ideas and the ways they help build an explanation of the phenomenon at the forefront of the work in our classrooms, we help the students, working together in groups and as a whole class, make sense of these scientific ideas and how they apply to the phenomenon. As this stage wraps up, we now have all the pieces we need to come to a complete evidence-based explanation of the phenomenon.

Stage 3: Building Consensus

The third stage, building consensus (Figure 4), is about pulling it all together. Throughout the unit thus far, students have worked together in groups to make sense of the tasks in the context of the anchoring phenomenon. Through discussions and share-out sessions, we have worked to coordinate their ideas so groups could learn from each other. In this stage of an MBI unit, the whole class works to build consensus about the explanation of the phenomenon by finalizing the groups’ models, comparing and contrasting those models as a whole class, and constructing a consensus checklist of the ideas and evidence that should be a part of students’ final evidence-based explanations that make up the summative assessment of the unit.

Figure 4. Building Consensus

As with the model revision that occurred halfway through the unit, finalizing the models requires the groups to review their previous models, decide what needs to be revised based on new ideas and understandings from the last set of tasks, and redraw the models so they can be more easily shared and used to build consensus in a whole-class setting. This usually takes about 30 minutes. We often scaffold this process by asking students to review the completed Summary Table and talk about what should be added to, removed from, or changed in their previous models. They should think about what new ideas can help them move toward a truly causal model that includes not only what happened but also why it happened. This requires that the mechanism at play be visible and well explained. We push the groups to make sure that items in their models are labeled, that any unseen components are made visible, and that the important ideas that surfaced throughout the unit are explicitly used in the models. There is a challenging tension here in that we want to provide guidance and encourage students to make the most complete and useful models they can, but we don’t want to provide so much guidance that the process of modeling loses its power and they just create the models that we want them to. As they work on this process, we walk around and press them for more detail and clarity, focusing on the evidence that does or does not support the various components and relationships in their models.

We think that a share-out session is needed again here so that the groups can learn from each other and begin to build consensus across the models. There are a number of ways to do this, including gallery walks. As the goal is to build consensus as a whole class, we usually opt to facilitate a share-out session in which each group comes to the front of the class, displays its model, and talks it through. We prompt students to ask questions, and the class works hard to compare and contrast ideas across the models. As the unit is near the end, we push harder here than we did earlier in the unit when we wanted to allow groups to have some ideas that were still not canonically correct or completely refined. We also want to encourage students to think about how well each aspect of the model fits with the evidence they generated during the unit and whether it is consistent with the core ideas and crosscutting concepts that were introduced during the previous stage of the unit. However, our goal is for students to do this work themselves.

At this point, the role of the models is over. They are not used for a summative assessment. Instead, they were just tools to help a group of students make sense of the ideas highlighted in the tasks and how they applied to the phenomenon. Now we shift to facilitating a discussion and building a new public record around our group consensus of the evidence-based explanation of the phenomenon. Some teachers like to build a whole-class model together in front of the class here. We think this works best for younger students and tend to move right to the construction of the checklist with our older students.

The goal of the final checklist is to have the class negotiate about which of the main ideas and evidence should be part of a complete and scientifically defensible explanation of the phenomenon. Students will use this as a scaffold for writing their final evidence-based explanations in the last stage of the unit. There are a number of ways to facilitate this discussion and creation of the public record. We like to prompt groups to create a bulleted list of the three to five most important ideas they think they need. We then ask for examples, press the whole class to make sure they understand how the idea fits in, and ask for consensus before writing it on the final checklist public record. This process can take about 15 to 20 minutes and most often goes quite smoothly by this point in the unit. However, this is also a time to make sure important ideas are included and to bring them up if necessary. While this is uncommon, we may also provide some just-in-time instruction to tie up any loose ends in the students’ understandings from the unit.

The checklist becomes less useful to students if everything that comes up in this discussion is automatically written on the board. Ideas can generally be combined into five to seven bulleted points. We then go back and lead a discussion about the evidence we have for each of the bulleted points and write those alongside. This step is crucial, as students will need to coordinate the science ideas with evidence in the written evidence-based explanation in the next stage. At times, we have been unhappy with our checklist for some reason; perhaps the writing is not as legible or the points are not as clearly articulated as we would like. In such cases, we created a clean version that evening and asked the students the next day to ensure that it still represented all the ideas from the original poster.

Stage 4: Establishing Credibility

Science does not progress just because a great explanation for a phenomenon has been developed. We have to argue for our explanations and convince others that they are valid before our ideas have credibility in the scientific community. Similarly, in MBI, students must argue for their ideas in writing to convince their peers and teacher that their explanations of the anchoring phenomenon are scientifically valid. In the fourth and final stage, establishing credibility (Figure 5), students do this through written evidence-based explanations, peer review, and revision. In MBI, their explanations are not just handed in for the teacher’s eyes only. Students engage in conversations with peers about the strengths and weaknesses of their arguments as they work to improve their final products. In this way, the revisions provide another opportunity for students to learn from one another as they consider and critique their peers’ explanations.

Figure 5. Establishing Credibility

This chapter has explained the basic concepts of MBI and its four stages, eliciting ideas about the phenomenon, negotiating ideas and evidence through tasks, building consensus, and establishing credibility. We hope this summary of MBI has sparked your enthusiasm to read further about how to apply this teaching method in your own classroom, using the example units we provide.

Reference

National Research Council (NRC). 2012. A framework for K–12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Academies Press.

CHAPTER 2

Framing, Tools, and Routines for Supporting MBI Instruction

This chapter builds on the vision for MBI laid out in Chapter 1 by framing what we have found to be the most productive stances toward teaching and learning in MBI units. This is important because the way people think about what they are doing influences the kinds of resources they may consider drawing on or the tools or strategies they may decide to use as they work to explain complex events that happen in the world. In this chapter, we provide a framework related to specific features of classroom environments (e.g., student ideas as resources, modeling, explanation, arguing from evidence) from both the teacher’s and students’ vantage points. Often, these two vantage points converge, as they are descriptive of similar activities; however, it is important to distinguish here between how the teacher and students might need to think about each of the different features of MBI. In the MBI learning environment, your role as a learned other responsible for meeting curriculum expectations for learning in biology, while concurrently supporting students’ engagement in authentic forms of sensemaking, can at times be different from the sensemaking role of students, who are focused on figuring out how to explain an event that happens in the world.

Given this aim, this chapter begins with some general principles for framing both teachers’ and students’ thinking about the MBI learning environment, including ways to think about equitable access and participation and student ideas as resources. Then these ideas, along with other stage-specific framings, are considered across the arc of stages of an MBI unit.

Equitable Access and Participation

Central to science teaching and learning is a focus on equitable access and participation, in terms of both who