UMassAmherst | College of Education

Developing Models in the Classroom

Discussion-Leading Strategies to Support the Scientific Practice of Modeling

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Core of This Teaching Approach

Of particular interest for teachers, curriculum designers, and other educators

Guided Model Improvement as a form of Guided Inquiry

This approach to science teaching pursues both content learning and scientific thinking by the student. In it the teacher aims to avoid the pitfalls of always using a pure lecturing or pure (open) inquiry approach. A third, very important approach is guided inquiry, here taking the form of guided model improvement. Broad outlines of the approach are illustrated in Figure 1. It has the virtue of both converging on content goals (the content of the models targeted by the teacher) and fostering student scientific thinking through the practice of modeling.

There are four boxes in a concept diagram: "Pattern to be Explained" leads to "Generate Initial Model" leads to "Evaluate Model" leads to "Modify Model." Then "Modify Model" leads back to "Evaluate Model." A comment under "Generate Initial Model" says "Brainstorming discussion without Evaluation." A comment under both "Evaluate" and "Modify" says "Guided Model Improvement Discussion." There is a vertical line that divides the entire diagram down the middle. On the left, "Pattern" and "Generate" are grouped under the larger category "Setting the Stage." On the right, "Evaluate" and "Modify" are grouped together under "Improving the Model."


Figure 1. Broad outline of the main approach

Example

A 7th grade class was studying pulmonary respiration. Figure 2 is a diagram of the lesson, showing the evolving model being constructed and improved by the students along with guidance from the teacher. The condensed transcript progresses from left to right, with teacher statements at the bottom alternating with student statements at the top.

In a large diagram of a class discussion, the evolving classroom explanatory model is depicted in a series of drawings that progress from left to right. Larger versions of these images are shown and described below on this page. Below the row of images is a row of teacher utterances in the order in which they were delivered. Above the row of images are student utterances. Arrows zigzag up and down throughout the diagram to show how a teacher utterance leads to a student utterance leads to a modified version of the conceptual model of the lungs being developed in this discussion. More detail follows on this page.


Figure 2. Diagram of first part of an actual Guided Model Improvement Lesson

Setting the Stage

The teacher first asks the class for ideas for how we breathe to get oxygen. This is the key question for the lesson and Identifies the Pattern to be Explained by the modeling activities to follow. She next asks them to work individually to “draw what a lung looks like.” When that is done, she asks the group to make a collective model on a white board. This is how the class Generates their Initial Model. In their first collective drawing, the lung is mostly hollow (a partially incorrect “balloon” model of the lungs; see Figure 3). Note that before receiving any instruction, the students have participated in Identifying a Pattern and Generating a Model, both of which contributed to Setting the Stage as depicted in Figure 1. These activities have been implemented in the context of an open brainstorming discussion. During this part of the class, the teacher has not evaluated ideas but has created a safe space for students to come up with their own ideas. Model evaluation will come later.

Hand drawing of what is essentially a single lung with a suggestion of two lobes. It has mostly hollow space inside with a hole at the top for air to get in and another hole at the bottom, presumably for the air to get out.


Figure 3. Hollow lung with hole

Improving the Model

In the initial model generated by the class, there is a hole at the bottom of the lung. (See Figure 3.) At this point, with a consensus model on the board and with students having had the opportunity to contribute ideas, the teacher shifts gears and moves away from the brainstorming discussion. She in effect crosses to the right side of Figure 1, where, unlike on the left side, a central feature of discussion is evaluation and critiquing. She begins by asking the students to Evaluate a Feature of their Model, “You have this sort of space here—do you think the air could sink out?” The students begin to worry about air leaving the lung through the hole and decide to improve their model by closing the hole. They Modify the Model, yielding the model in Figure 4.  

This part of a modeling lesson tends to be cyclical with repeated rounds of evaluating and modifying the model, and that occurs here. A student evaluates the evolving model using an impromptu empirical investigation. She breathes in and out deeply and loudly, and says, “Because you need to hold the air in your lungs and it comes back out the same place.” This informal qualitative exploration leads her to evaluate the revised model favorably because it supports having the hole closed; the student seems focused on whether about the same amount of air goes in and comes out.  Thus, the students are participating in model evaluation and modification processes along with the teacher.  

Next, the teacher guides the students to notice another aspect of their model that needs evaluating.

Hand drawing of hollow lung very similar to Figure 3, but with the hole at the bottom closed up. The overall shape is a bit like a kidney or inverted heart.


Figure 4. Hollow lung without hole

Most of the students think that we have a single lung made up of one large cavity, as in Figure 4. The teacher initiates another cycle of evaluation and revision as shown in Figure 2 by asking, “Have you ever heard of anybody having a lung taken out?” Students agree they know of such operations and decide that there must be two separate (mostly hollow) lungs (Figure 5).

Now there are two lungs, still hollow, with a few circles in a small cluster that suggest alveoli.


Figure 5. Two hollow lungs

Another evaluation and revision cycle takes a different form. The teacher and students discuss that they know oxygen has to be provided for a huge number of cells in the whole body. The teacher asks if the space in the middle of the lung is being used for anything, hoping to trigger more evaluation and to suggest the need for further modification. However, the students do not come up with a modification, so the teacher decides to directly Provide A Modification to the Model by telling the students that the lungs are filled with tissue and are not “hollow and balloon like.” She also lets them know that the tissue has a multitude of cavities with air in them. This illustrates how moments of direct instruction can be part of a guided model improvement lesson—such lessons are quite different from pure (open) inquiry (and from pure lecture). The teacher’s contribution to Improving the Model leads to the model in Figure 6. (An alternative seen in other classes is to have the students examine a real pig’s lung at this point to see that they are definitely not hollow.)

The lungs are filled with hand-drawn squiggles, showing that they are not hollow. However, there is no indication of internal structure other than the small cluster of alveoli retained from the version in Figure 5.


Figure 6. Two lungs with tissue with a multitude of cavities

The student drawings still show the air passageways and cavities too few in number to hold enough air. At that point the teacher sets up an empirical breath measurement experiment where students use long plastic bags to measure how much air is contained when they blow out a deep breath. The surprisingly large results of these measurements suggest to the students that the passageways and cavities drawn in their model are not enough—there must be many more of them. The experiment provides an evaluation of the model in Figure 6 and the result is another model modification, shown in Figure 7.

This hand drawing is like that in Figure 6, with the addition of alveoli clustered along branching tubes that spread through out the cavity.


Figure 7. Two lungs with tissue with more cavities

The class is only half way to the target model (the instructional objective of the lesson) at this stage, but they have made significant progress. Later in the lesson, with scaffolding from the teacher, they will add an exchange mechanism between air in the alvioli and blood in the surrounding blood vessels. This illustrates how, during the discussion led by the teacher, the students’ model is improved in small steps, making it more and more like the target model for the lesson. This stepwise approach is necessary for models that are too complex to be learned in one fell swoop, and helps them see the functional reasons for the way the lungs are structured. Because the students are supported (‘scaffolded’) by the teacher as they participate in generating, evaluating, and modifying models, we call the overall process ‘teacher-student co-construction’.

Important!  Distinguishing between Observations and explanatory Models

The above example illustrates the difference between empirical Observations and explanatory Models.  Observations include the fact that people cannot live without breathing,  can continue to live after one lung has been taken out, and that the plastic roll out measuring instruments show that one’s lungs contain quite a lot of air.  The drawings on the other hand are explanatory Models in various stages of revision that are attempts to explain how the body gets oxygen, in a way that fits all the observations we can make about breathing.  

Throughout this website, we will distinguish between Observations that are things we can agree on seeing or detecting, and explanatory Models that are our theories about what is ‘hidden below the surface’ and causing those observed properties or behaviors.

There are also other modeling phases and modes of discussion in some Guided Model Improvement Lessons that are not shown in Figure 1. These will be discussed in the Full Theory and Strategy Catalog sections of this site. For now, suffice it to say that the lungs unit ended with an additional Model Consolidation mode, where the teacher played an animation summarizing the target model. The animation showed aspects of the target model the students were not expected to come up with during discussion. However, they were now well prepared to absorb this information, and they used the new information to modify individual drawings of the model they had made earlier.  This served to consolidate the target model for the students and brought the unit to a close.

Classroom Modes and Modeling Phases: Levels in a Framework

The two broad Classroom Modes discussed above are Setting the Stage and Improving the Model, both at the top level of the modeling framework. Each of these Modes receives contributions from Modeling Phases, shown below them.

The Teacher Adjusts the Style of Discussion to Fit the Current Modeling Mode

A three-column table outlines the phases of a modeling lesson: “Setting the Stage,” “Improving the Model,” and “Model Consolidation and Articulation.” Each column describes the Modeling Mode, Type of Discussion, and Description for the phase. • Setting the Stage: Involves identifying a pattern to be explained and generating initial models. The type of discussion is “Brainstorming: Models without Teacher Evaluation.” Description notes that either teacher or students identify the pattern, and students generate models without class evaluation. • Improving the Model: Involves evaluating and modifying models in a cycle. The discussion type is “Guided (Inquiry) Model Improvement,” where students refine models with teacher support toward a target model. • Model Consolidation and Articulation: Focuses on finalizing models. The discussion type is “Direct Instruction with Discussion,” where the teacher summarizes and provides final model elements while small groups finalize their models and evidence.

Table 1: Modeling Modes and Different Types of Discussion

The top line in Table I shows Modeling Modes that form the heart of the Modeling Strategies Framework. They require different Classroom Discussion Modes as seen in Table I. They are in turn supported by more detailed strategies that will be illustrated elsewhere. These lower level strategies are ones we see many teachers using intuitively in inquiry lessons—e.g. using analogies, asking for drawings, asking students to explain their thinking. In this site we show how skilled teachers deploy these in a coordinated fashion to support the modeling phases above. The hope is that by explicating what experienced modeling teachers often do intuitively, this teaching approach can be taught, discussed in education courses, and brought within the reach of many more pre- and in-service teachers.

Advantages of this Teaching Approach

  • The teacher is gaining diagnostic feedback on student thinking, and therefore insights into the many conceptual pieces that need to be learned or unlearned; Both teacher and students contribute ideas and evaluations of ideas.
  • Even though 30-50% of the ideas will come from the teacher or readings, there is still a very active idea generation and reasoning role for the students in Guided Discussion.
  • There is the resulting potential for many students to become engaged in scientific reasoning.
  • There is the resulting potential for many students to change from just trying to memorize facts to trying to make sense of concepts.
  • Students share and listen to each other’s ideas to build a community of learning.

Small group discussion as an important complement

Although this site focuses on whole class discussion strategies, it is important to note that most modeling teachers also utilize individual and especially small group activities. For example, they may conduct the initial Model Generation activity in Figure 8 by assigning it to small groups using small portable white boards or poster paper to record a model drawn jointly by the group. These can then be displayed to the class to fuel a whole class discussion of the models.  Students who are not used to working in small groups productively must be taught the norms and skills for small group work and this can take some time at the beginning of the year. (A good resource for developing small group teamwork is Kagan, S., & Kagan, M. (2009), Kagan Cooperative Learning.)

We have also included a description by a middle school teacher of how he builds up norms for small group learning here.

That said, most of the strategies described on this site can be used by the teacher to scaffold small group discussions as well as whole class discussions.

Where to Go Next

  • We suggest you look at the Educator’s Tour section if you have not done so already.
  • The Strategy Catalog section lists and gives examples of all strategies organized by levels.
  • The Course Syllabus Ideas section contains suggestions for using this site as a resource for a graduate course. It includes ideas arising from experience teaching aspects of this material in courses for pre- and in-service teachers. Teachers who want to self-instruct can also use the exercises and videos accessed from the Syllabus Ideas section to gain a more in-depth understanding of strategies that support modeling.