When you hear the word “model,” what comes to mind? Perhaps it’s a solar system assembled from retired baseballs, basketballs, and table tennis balls. Or maybe it’s a colorful clay representation that highlights the organelles of a plant or animal cell. It may even be a drawing that illustrates the observed stages of seed germination.
Although these are historic and familiar examples of models, the Next Generation Science Standards* look at expanding the role of model from that of sole representation of an idea or explanation to something more—something that can be used to make predictions or help explain phenomena.
As you may be aware, Developing and Using Models is profiled as one of the NGSS Science and Engineering Practices. Like the other dimensions, it is presented as a sequential skill set that expands in coverage and increases in sophistication as we move upwards through the grade bands, building upon previous cached knowledge.
Models for Young Students
In kindergarten through grade 2, the concept of scientific and engineering models reflects more of a static representation of a natural-world concept. At this level, it is not essential to incorporate dynamics into a behavioral aspect of the model; that comes later. At the K–2 band, we are more interested in the representations of events and design solutions. Therefore, diagrams and drawings remain quite valid as communication devices, as do physical replicas. The exploitation of storyboards is also a powerful tool in displaying the elements of a sequential event. Even the old shoebox diorama retains its role as a communicator of structure or events.
However, when afforded the opportunity, students should be encouraged to build additional understanding through the analysis of their model. For example, suppose they have constructed that familiar solar system model. Even with its out-of-scale representations, it is a viable landscape on which to make predictions. Children can be challenged to predict and draw inferences on how a relative distance to the sun impacts a planet’s climate. Based upon observations of their model, will the inner planets be warmer or colder? But of even greater importance is why? As you can see, the model’s role rises to something more than a finished piece of art that hangs from the ceiling and assumes the role of conceptual landscape.
How Models Evolve as Students Get Older
As students move through the grade bands, the concept of model evolves in sophistication so that it integrates more of the dynamics of a system whose inputs impact outcome. For example, in constructing a model of osmotic pressure that affects a cell’s volume, you produce a functional classroom model that mirrors real-world physical behavior driven by diffusion. The dialysis bag model will respond to hyper- or hypotonic immersion by shrinking or swelling, as an actual cell will do.
Another critical component of developing and using models is uncovering the shortcomings of a model. This critical analysis of model validity begins in the primary band and continues through high school. Throughout their experience with developing and using models, students are continually evaluating the model, and based upon their further understanding, improving its validity through revisions.
Models at the High School Level
By the time students arrive in high school, their understanding of models—along with higher mathematical and computational skills—can be applied to understanding the mechanisms of events, as to produce increased validity in outcome prediction. As profiled by NGSS, the incorporation of computer models is an experience in which students apply essential technology to a variety of situations, including the engineering design process.
As you can see, Developing and Using Models remains a viable tool in our everyday classroom arsenal. The major change in pedagogy as profiled by NGSS is in elevating its role from merely a finished “wall hanger” to something that can be further analyzed or explored to distill out a higher understanding on which predictions and inferences can be made.
Click here to view Michael DiSpezio's webinar, Developing and Using Models: A Hands-on Webinar for All Grade Bands!, from Wednesday, May 9 at 7 p.m. Eastern Time.