MBI Guides #2
How to Engage Students in
Developing and Using Explanatory Models
Written by Alexa Young (Marquette School of Excellence) & Alissa Berg (AUSL Science Coordinator)
What are explanatory models and how do they improve student
learning?
When you hear the word “model” you might immediately think of the smallscale 3-dimensional replicas of buildings used by architects or the typical
animal cell model your teacher had you make when you were a student. In
science, the term “model” refers to a simplified representation of a system that
is used to make predictions or explanations for a phenomenon. Scientific
models are “judged on both how simple they are and how well they can be
used to explain and predict natural phenomena” (Jadrich & Bruxvoort, 2011, p.
12). Using this definition, the 3D cell model or a drawing of the rock cycle
found in so many textbooks are NOT scientific models in and of themselves.
They are simply representations (unless used to explain or predict).
Memorizing the steps in a cycle or the parts of a cell are not the end goal in an
NGSS classroom.
According to the Next Generation Science Standards (NGSS), scientific
models may include: diagrams, physical replicas, mathematical
representations, analogies, and computer simulations (see NGSS Appendix F).
But, again, keep in mind that they must be used to predict or explain phenomena. In this guide, we focus on one
specific type of modeling that is particularly helpful for supporting and deepening student learning: “explanatory
models.”
Explanatory models are a combination of pictorial representations and written explanations that describe how and
why a particular phenomenon occurs. Here are a couple of examples of what these types of models can look like:
How and why do TUMS help get rid of heartburn/stomach aches?
(Mary Clark, 2014, Solorio Academy High School)
Created in 2015
How does Ebola infect and kill a person?
(Darrin Collins, 2014, Phillips Academy High School)
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What are explanatory models and how do they improve student
learning? (continued)
Explanatory models accommodate different
learning styles. They don’t just stop at
reading and writing, they allow students to
visually represent their thinking (i.e.,
through drawing). Research shows that
having students draw out their explanations
supports learning (Ainsworth & Iacovides,
2005). Asking students to represent their
ideas through illustrations provides a
window into their thinking for the teacher
and supports students in making sense of
the content. Drawing is not only a helpful
strategy for ELL and diverse learners who
struggle with writing, but for all students.
3 Key Aspects of Scientific Models (Schwarz et al., 2009)
Include specific variables or factors within a system under study.
Represent the relationships among components (i.e., variables/factors) in order to provide an account of why the
phenomenon occurs.
Sequence these variables, factors, and relationships into a causal storyline to explain a phenomenon.
As students acquire new learning and evidence over the course of a unit, they need periodic opportunities to revisit
and revise their explanatory models. Explanatory models require students to use science principles and ideas to
explain real world events/occurrences. Stated another way, explanatory models require students to relate the
observable (effects) to their unobservable (causes). According to the research synthesized in the publication, How
People Learn, “To develop competence in an area of inquiry, students must...understand facts and ideas in the context
of a conceptual framework, and...organize knowledge in ways that facilitate retrieval and application” (NRC, 2000, p.
12). It follows that developing models to explain how and why phenomena occur strongly aligns with research on
effective teaching and learning.
NGSS outlines 8 Science and Engineering Practices in which students should regularly engage in order to learn the
science content. “Developing and Using Models” is the second of these eight practices.
Check out this TchAUSL video to see how 3 AUSL teachers have implemented explanatory models in their classrooms.
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What is the ultimate goal of engaging students in constructing
and using explanatory models in the classroom?
Students create initial models at the beginning of the unit (to elicit their initial ideas/predictions), revise them in
the middle (once or twice) based on new learning, and then create a final model at the end (tying together their
learning throughout the unit).
Students defend their additions/revisions to their explanatory models using evidence from sense-making activities
(i.e., any classroom activity that supports students in deepening their content knowledge: investigation,
simulation, reading, etc.)/summary chart.
Students are able to connect the unobservable (causes) to the observable (effects) in their explanatory models.
Students are able to use their explanatory model to make predictions or explain how and why phenomena occur.
Students are able to apply their learning to explain how and why a new, related phenomenon occurs (to show that
their learning is transferable).
How can I start incorporating explanatory models
tomorrow?
The easiest way to get started with modeling is to begin by asking students to do
more drawing (i.e., represent the concepts they are learning pictorially). For
example, ask students to draw what they think is going on when a liquid
evaporates, or better yet, draw how they think a puddle disappears after it rains.
While explanatory models for big questions, such as “How can we smell the
cookies baking at the factory 10 blocks away,” requires students to connect and
synthesize several science ideas in one explanation, the modeling activity to the
right was used to have students explain a single concept: air compression in a
syringe. If you are new to modeling, we recommend starting by having students
draw pictures of their ideas around a single concept. As you and your students
become more comfortable, you can start asking them to draw models to explain
or predict more complex, multi-concept, questions.
Things to keep in mind as you get started with modeling
Don’t give the answers away! Let students struggle.
Why is it difficult to push in the
plunger of a syringe filled with air is
pushed in when your finger is
covering the opening?
(Alexa Young, 2015, Marquette School of
Excellence)
Respond to students’ questions with questions (e.g., What did you observe?
What do you think it means? Why do you think that? Where have you seen something similar?)
Give them time. Allow them to share ideas with each other and edit their models.
Discuss and agree on common drawing conventions (e.g., how to draw different types of particles, how to show
motion, how to represent different speeds, etc.)
Use “zoom-in’s” (like the picture of the syringe above) and ask students to use “microscope eyes” to illustrate and
explain things that are invisible to the naked eye (e.g., layers of the earth, gases, etc.)
Have students label with arrows and/or make a key/legend.
Have students describe what’s going on in their pictorial models through writing (in full sentences).
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How to become an explanatory models expert.
Here we describe a pathway for planning and enacting instruction that engages students in developing and using
multi-concept models (i.e., explanatory models in which students synthesize the evidence-based ideas they are
learning over the course the unit to answer a big question).
1. Puzzling Phenomenon: Come up with a rich puzzling phenomenon to anchor your unit [see the “how to” guide for
coming up with “good” phenomena]. For example, “Why does the metal leg of the table feel colder than the lab
tabletop even though they are at the same temperature?”
2. Storyline (Underlying Explanation): Do your own research on the topic and the content from NGSS to create your
own explanatory model for the phenomenon. This step is critical! If you don’t have a clear storyline in mind, you
won’t have an idea of how to support students in developing their explanations.
3. Initial Models: After you introduce the phenomenon to students through an anchoring activity (e.g., a video,
recounting a story, a demo, a hands-on activity, etc.), ask
students to draw, label, and write complete sentences
explaining their initial ideas about how and why they think the
phenomenon occurred. Be careful that the anchoring activity
does NOT give away the explanation. It is important that
students walk away from the first lesson wanting to learn
more!
Some things to note:
Create a model template: Students can get preoccupied
with aesthetics, when you really want them spending their
time thinking about and explaining the phenomenon.
We’ve found it helpful to provide students with a model
template that includes any difficult-to-draw components.
Check out these examples of initial model templates:
How and why did Jennifer Strange die from a
water drinking contest to win a Wii? (Initial
Model Template)
Management: For initial models we recommend having
students get their individual ideas down on paper first, then work in small groups to discuss and build on each
other’s ideas as they co-create a small group model that illustrates their hypotheses about how and why the
phenomenon occurred. One way to promote equitable participation in group work is to have each student make
their contributions in a different color.
Use students’ initial ideas to inform future instruction: Although you have already created a storyline for your
unit ahead of time. Eliciting students’ ideas through initial explanatory models is helpful for tailoring your lessons
to meet your students’ particular needs. Based on what you learn from students’ initial models, you may end up
skipping an activity, supplementing an activity, or making sure that you target a specific idea in an activity you
had already intended to teach.
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How to become an explanatory models expert (continued)
4. Revisit and revise models: Over the course of the
unit, provide students with opportunities to
periodically go back to their models (or start on a
fresh sheet of paper) to:
Add new ideas based on evidence (from sensemaking activities/summary chart).
Revise ideas that are not supported by evidence
(from sense-making activities/summary chart).
Pose questions or new directions for inquiry.
Discuss conflicting ideas (students may have two
opposing theories for how and why the
phenomenon occurs that should be explicitly
discussed as a class or in groups).
We recommend having students get their ideas
down first, next moving to small groups, and then
using the following approach to create or revise a
whole class consensus model:
How can we smell cookies baking at the Nabisco factory ~10
blocks away? (Final Model Template)
Alexa Young, 2015, Marquette School of Excellence
Consensus model:
As students are working on their small group models, the teacher circulates and strategically asks a
representative from each group to add one specific piece of the explanation to the whole class model (on
chart paper, digital interactive whiteboard, or document camera) at the front of the room (note: you may
highlight ideas that students have a firm grasp on or a common misconception you wish to address with the
class).
2. After each group has added to the class model, a representative from each group presents their piece of the
explanation to the class for discussion (modifications can be made based on evidence and consensus from
the class). We like to indicate our level of confidence in the various aspects of the whole class model in one
of two ways:
a. Use symbols: “!” or “$” to represent ideas we are confident about (i.e., we have strong supporting
evidence), “x” out or strike through any ideas we’ve been able to refute, and “?” to indicate the ideas for
which we need additional evidence.
b. Use colors: Green to represent ideas we are confident about (i.e., we have strong supporting evidence),
red to strike out any ideas we’ve been able to refute, and yellow (or orange) to indicate the ideas for
which we need additional evidence.
1.
5. Use models to make predictions about new related phenomena, as well as to make predictions about the
outcomes of labs/investigations students are about to do. If the model correctly predicts the new situation,
students now have further evidence to strengthen their ideas. If the model does not correctly predict the newly
introduced situation, then the model may need to be revised to account for this new scenario/data. This is
precisely how science works and why this approach to instruction is much more authentic than the overly
simplified scientific method taught in many schools.
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How to become an explanatory models expert (continued)
6. Create a final explanatory model: At the end of the unit, have students create their own, individual, explanatory
models to assess learning. Here are some tips:
Include a checklist of “must-haves” that students are required to address in their model. Ideally this list is
generated along with your students over the course of the unit to keep track of the keep elements required to
fully explain the phenomenon. Because it’s generated with the students, the checklist may look a little different
from class to class. Nonetheless, the core ideas, aligned with NGSS, must be included (even if worded
differently).
Use 11x14 paper (more space = more information from students).
It is ok if students explanations don’t all look the same. These may still have some conflicting theories about how
and why the phenomenon occurs. What you are really looking for is that the key concepts learned are accurately
explained and that students are citing accurate evidence for their claims.
In addition to the TUMs and Ebola models at the beginning of this guide, here are a couple more examples of
students’ final, individually created, explanatory models:
Why is there such a difference in the physical
appearance of twins, Kian and Remee?
Why does the metal leg of the table feel colder than the lab tabletop
even though they are at the same temperature?
(Sarah Rogers, 2015, Howe School of Excellence)
(Tim Nystrand, 2014, Solorio Academy High School)
7. Apply learning to a new related phenomenon: This is where you check to see whether student learning is
transferable. Did they really learn the concepts that we wanted them to? Can they apply those science ideas to
explain other appropriate phenomena? For example, after students learned about why the Top Thrill Dragster
roller coaster in Ohio doesn’t always make it over the peak (and sometimes rolls backwards), they were then
asked to explain why the following event occurred as it did:
A bowling ball, suspended by a rope from the ceiling, was pulled to one side of the room so that it was touching a
man’s nose. When it was released, it swung like a pendulum to the other end of the room and upon its return it
narrowly missed hitting the man in the face. You can watch this video here.
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How to become an explanatory models expert (continued)
8. Our Modeling Tips:
Avoid model burnout: Only have students
create multi-concept models for the
phenomenon once at the beginning at the
unit (initial model), once or twice during the
unit (revisit and revise), and then once at the
end of the unit (final explanation).
Make learning public: Display the latest
consensus model or models of students’
alternate theories for all to see and
reference.
Maximize time: Keep students focused on
the content rather than the aesthetics of
their model by having hard-to-draw
components of the model already included in their model template.
Zoom-in’s: Have students use zoom-in’s to get at the unobservables causes for the observables effects
Templates & chunking: Create model templates for students break up the phenomenon into smaller segments of
time (e.g., before-during-after) or conflicting situations
Common conventions: Require a legend/key and agree on conventions/symbols for models (how you will
represent atoms, speed, changes in temperature, etc.)
Learning from student work: Showing and dissecting examples of good explanatory models will help students
better their own.
Communicating: Strategically select students to share their models (i.e., models that explain a key idea well or
include a common misconception you want to debunk) and have their peers ask them questions.
How do explanatory models align with Model-Based Inquiry?
Based on its name alone, it’s clear that MBI is inextricably linked to modeling. Developing, testing, revising, and
evaluating explanatory models is the skeleton around which MBI units are designed. For each unit, you change the
phenomenon and you change the content/science ideas addressed, but you go through the same modeling process:
1.
2.
3.
4.
develop initial models;
revisit, test, and revise models to improve their predictive and explanatory power;
create final models; and
apply learned science ideas by creating an explanatory model for a new related phenomenon.
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How do explanatory models align with NGSS?
Not only are explanatory models at the heart of MBI, but they are at the heart of science in general! “The primary
goal of science is the construction and evaluation of scientific models” (Jadrich & Bruxvoort, 2011, p. 12). All of the 8
science and engineering practices outlined in NGSS are tightly tied to modeling. Put modeling at the center of your
classroom and you’ll find innumerable opportunities to weave in the other practices integral to the scientific
endeavor. Since modeling is salient to MBI, this further reinforces why MBI is such an effective approach to planning
and teaching science in line with the vision of NGSS.
References
Ainsworth, S., & Iacovides, I. (2005). Learning by constructing self-explanation diagrams. In 11th Biennial Conference
of European Association for Research on Learning and Instruction, Nicosia, Cypress.
Jadrich, J., & Bruxvoort, C. (2011). Learning & Teaching Scientific Inquiry: Research and Applications. NSTA press.
National Research Council. (2013). Next Generation Science Standards: For states, by states. Washington, DC:
National Academies Press.
Schwarz, C. V., Reiser, B. J., Davis, E. A., Kenyon, L., Achér, A., Fortus, D., Shwartz, Y., Hug, B., & Krajcik, J. (2009).
Developing a learning progression for scientific modeling: Making scientific modeling accessible and meaningful for
learners. Journal of Research in Science Teaching, 46(6), 632-654.
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