Modeling for Understanding in Science Education

Explanatory Models in Science

A scientific model is an idea or set of ideas that explains what causes a particular phenomenon in nature.

We are interested in models from the perspective of what practicing scientists actually do. The most important overall goal of scientists is the development of an understanding of how various parts of the natural world work. To do this, scientists make observations, identify patterns in data, then develop and test explanations for those patterns. Such explanations are called scientific models.

It is important to note that scientists use drawings, graphs, equations, three dimensional structures, or words to communicate their models (which are ideas and not physical objects) to others. However, the drawings, replicas or other tools are distinct from the underlying models they purport to explain.

Explanatory models in science are continuously judged by a community of scientists. To evaluate a particular model, scientists ask:

  1. Can the model explain all the observations?

  2. Can the model be used to predict the behavior of the system if it is manipulated in a specific way?

  3. Is the model consistent with other ideas we have about how the world works and with other models in science?

In judging models, scientists donít ask whether a particular model is "right". They ask whether a model is "acceptable". And acceptability is based on a modelís ability to do the three things outlined above: explain, predict, and be consistent with other knowledge. Moreover, more than one model may be an acceptable explanation for the same phenomenon. It is not always possible to exclude all but one model Ė and also not always desirable. For example, physicists think about light as being wavelike or particle-like and each model of lightís behavior is used to think about and account for phenomena differently.

Finally, we note that in practice, models are continuously revised as they are used to probe new phenomena and collect additional data.

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