IV Classroom Modes: Model Consolidation and Application

The goal of classroom activity is to converge on a consensus model and to apply it to new situations.

This is where the students begin to use the model to see how it can be used to predict what will happen in a new situation. This is an important aspect of scientific modeling; a model is not just a construction to be handed in, but something to be used.

However, before students begin applying the model to new situations, the class first needs to converge on a consensus model and be clear about what that is. The teacher has an important role to play during Model Consolidation, before the class tries applying the model to new situations. The two related examples can illustrate.

This image contains three drawings, starting at the top with the one from Example 3 in Model Competition and moving downward to show two model revisions. Top: Black wavy lines extend along the top and bottom of the image, representing villi-lined intestinal walls. (Each wave represents a villus.) Green dots between the lines represent nutrients in the intestines. Students have added hand-drawn lines in red to represent their models of how the capillaries would be arranged in the villi. Model A has three vertical lines inside the intestinal wall, near a villus. Model B has a wavy red line following the surface of villi, inside the intestine next to the nutrients. Model C has branching tree-like structures inside each villus. Middle: This is the Class Consensus Model, a single model agreed upon by the class. The drawing is a closeup of two villi. Each one has a red capillary going in from the bottom and up to the tip, turning into a blue capillary that comes back down and out. Bottom: The expert model, which was the target model for the lesson, was shown on an overhead slide. It is very similar to the class consensus model. It has an addition: a red Arteriole and a blue Venule running along beneath the villi and parallel to each other. The red capillary branches off the red Arteriole and the blue capillary returns to the blue Venule. Capillary, Arteriole, and Venule are all labelled.

Example 1: Model consolidation

Teacher and students had been discussing where to locate capillaries with respect to the villi in the small intestine for an anatomical design that could maximize nutrient absorption. The students had come up with three ideas, drawn in red (top). After much discussion in which students and teacher had evaluated and modified these models, the class came to a consensus that villi are finger-like structures that have one capillary inside that can be represented as a red and blue loop (middle). The teacher then showed the students transparencies of actual electron microscope photographs of villi along with artist renderings of the the internal structure of villi (bottom). They discussed the meaning of the red and blue blood vessels. The teacher then asked the students to depict the exchange process that happens at the intestine, and the students wrote and drew in their workbooks. At this point, all students were “on board” with the target model; they could understand it thoroughly because they had reasoned through its components and arrived at the necessity of most of those components themselves; it was a small step from the class consensus model to the expert model depicted in the transparency.

Example 2: Model application

The hand-drawn image is of lungs, showing two lobes. Inside each lobe are branches, each branch ending in a small cluster of what look like grapes. These represent alveoli. There are five bunches in one lobe and six in the other. These are drawn in black. Red lines entering each lung and encircling each bunch represent blood vessels surrounding these tiny air sacs. A red shape underneath the lungs may represent the heart.Later, the teacher brought this model back to the attention of the students and invited them to apply it in a different situation to see whether it might fit. At this later point in the unit, the class was investigating how the oxygen moves from lungs into the blood and how carbon dioxide moves back into the lungs. She told the students that air passages in the lungs look like a bunch of grapes, and after some whole-class discussion about this, showed them a transparency of the alveoli surrounded by red and blue blood vessels (similar to the figure on the right). They discussed how the closeness of blood vessels to a source of essential substances is similar to and differs from the arrangement of capillaries in the intestine. Thus, the teacher not only supported closure for different ideas in the lesson, but helped students to integrate and distinguish between their models for two different functions in the body by considering to what extent their earlier model could and could not apply in the new situation.

Example 3: Model application - apply model to a new case

Teacher: Can our model of how oxygen transfers to the capillaries explain why people feel weak when the body stops making red blood cells and the cell count goes down?

Example 4: Model application - integrate the new model with an older model to form a chain of explanation

Teacher: Now that we know how sugar gets into the blood, and what the sugar in the blood is for, why do you think eating candy could help you to finish a long hike?

 

Supporting and Contributing Strategies

Model Consolidation and Application evaluates the relevance of the model to the new situation rather than evaluating the model itself. Even so, useful teaching strategies can be found here:

III.  Evaluating a Model
II.  Support Evaluating a Model

There are many Visualization strategies that may be helpful. Among them:

I. Depictive Gestures
I. Scientific Drawings
I. Mental Simulations

 

Background

Some of the background for this category of discussion, and how it fits into the larger framework, is in the Level IV section of the Educator's Tour.

For more discussion on the theoretical underpinnings of this part of the framework, see the Introduction to the Full Theory page.

 

Articles, Papers and Websites

More in-depth discussion is found in the following paper by our team:

Large scale scientific modeling practices (Nunez-Oviedo & Clement, 2019)

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