How Do Students Learn from Models? — Case Studies in Guided Inquiry

By Robert Tinker

We knew that we wanted to use global climate change to capture student interest because learning is always more vivid if it connects to real-world issues. Climate change is in the news and will be for a long time to come, so students are certain to be curious about the topic. From an educational perspective, the topic is loaded with opportunities to teach science content, science inquiry, computational models, statistics, and technology (not to mention politics, economics, and social studies).

Figure 1: A snapshot of the NetLogo Global Climate Change model. When run, there is a lot going on, but the model has tools for supporting careful investigation. It can be slowed down and run with different settings.

But we were stymied by the complexity of climate modeling. The debate about climate change is really a debate about models: how they are constructed, what variables are used, how they are verified, and what their results mean. How can we give middle and high school students an introduction to these issues without overwhelming them with detail? And more practically, how can we find an appropriate model that we can afford with limited resources?

“We” in this case is a team of researchers who are participating in the Center for Technology Enhanced Learning of Science (TELS). One of several Centers for Teaching and Learning funded by the National Science Foundation, TELS studies student learning with highly interactive environments using a knowledge integration design. The science content provides better ways to teach state and national standards that teachers have found difficult. The materials are software-based and generate student data used in our research.

We initially looked for existing climate models that we could use or adapt, but all had fatal problems. Either they didn’t run on both Mac and Windows operating systems or they were too complex or clunky. Since their source code was unavailable, we couldn’t fix these limitations. We did find a set of mathematical equations that might work, but saw no way of implementing them in the TELS platform. We almost settled for a Flash animation that showed some of the issues involved in the greenhouse effect, but we wanted a better approach that supported student experimentation with the model.

NetLogo and StarLogo to the rescue

What at first we thought was too difficult—namely, creating our own model from scratch—proved to be quite easy using NetLogo. We had already used NetLogo in our Modeling Across the Curriculum project, so we had the technology needed to integrate any NetLogo model into the TELS platform.

It is a mistake to think that languages for children, such as BASIC, AgentSheets, HyperScript, and Logo are toy languages, suitable only for kids. As Seymour Papert has pointed out, Logo has “no threshold, no ceiling.” NetLogo is an implementation of Logo that supports multiple “turtles” (programmable objects), which can be anything. In the Global Climate Change model, for example, the turtles are used to represent packets of solar energy, people, clouds, and carbon dioxide.

The joy of Logo in general and NetLogo in this case is that it is easy to create a sophisticated application with minimal effort. Having never programmed in NetLogo, it took me only a weekend to create working versions of the two climate models needed in the project. The models have various slider inputs, a stunning animated graphic representation (see Figure 1), and graphical outputs. Most importantly, the graphic helps explain what is going on. Students can trace the fate of a packet of sunlight. Such a packet might get reflected off a cloud or absorbed by the Earth. The more that are absorbed, the hotter the Earth gets. As it warms, infrared energy packets are emitted that go through the clouds, but can be reflected by greenhouse gasses. In the second model, population growth, factories, and pollution abatement strategies are introduced. Students can discover, for instance, the minor impact of clouds and the connection between birth rates and climate.

Figure 2: Part of the Global Climate Change program using StarLogo’s graphical programming language. Programming consists of dragging the right blocks into the structure and entering some values.

Eric Rosenbaum has created StarLogo versions of the Global Climate Change models. StarLogo v3.0 is an open source cousin to NetLogo that features a graphical programming interface that makes it even easier to develop code. In StarLogo, programming consists primarily of combining programming blocks that fit together only in certain ways. As a result, it is impossible to make a syntax error, and it is far easier to visualize the function of program parts (see Figure 2).

Guiding model-based learning

Students learn many science topics best through guided exploration. Exploration without guidance is too chancy and takes too long. Guidance without exploration is just another form of direct instruction that relies more on memorization than reasoning. From this perspective, the Logo climate models, while lovely, represent an incomplete learning experience. They need to be converted into guided activities by providing help, context, background, commentary, challenges, and opportunities to share models and ideas. The models need to be set up with different initial conditions and questions.

All these additional functions are provided by the TELS platform, which represents a synthesis of WISE and Pedagogica. WISE, developed at the University of California at Berkeley, is a stable web-based environment that features easy activity development and good reporting for teachers and researchers. Unfortunately, large applications like NetLogo that are best executed on client computers do not fit easily into WISE. Pedagogica, developed at the Concord Consortium, is a client-side environment that is completely flexible, but requires a programmer to write student activities. Their synthesis into the TELS platform represents an important milestone that will simplify authoring and delivering guided inquiry activities that use powerful client-side applications like Logo.

The Global Climate Change model is used in two TELS activities: a middle school Global Climate Change activity designed and studied by Keisha Verna and a high school Chemical Reactions activity created and studied by Jennie Chiu. They recorded how long students used the models, how many times they ran the model, and how they explored the variables. Both TELS researchers found evidence that experimentation with the model, combined with other features of the activities, resulted in deep, integrated learning.

Conclusions

Out of a conviction that the very best way to understand a model is to build it, NetLogo and StarLogo were designed to make it easy for children to construct models. But model building may not be the best way to understand complex topics like climate change. Inexperienced children can easily get the model wrong. It takes care and insight to create a model with the right combination of variables, equations, and controls to incorporate the central ideas and generate realistic behavior.

If the goal is to convey some particular math or science content, guided exploration of a completed model is a far more effective and efficient educational strategy. This suggests that languages like the Logo dialects should be thought of as development tools for materials designers who are attempting to convey complex concepts such as global climate change. For us, the fact that Logo can be embedded in a platform like TELS is particularly important because a full range of scaffolding and assessment options can then be used. The combination of the evolving TELS platform and modeling languages like NetLogo and StarLogo greatly simplify the creation of activities that guide student learning of complex content.

Robert Tinker (bob@concord.org) is President of the Concord Consortium.