*743*

Models represent reality. Students may think of a model as a physical object, but a scientific model can be a formula, a Punnett square, a labeled diagram, or computer simulation. A good model is explanatory and predictive. Models are based on observations or data.

Students should be able to apply a model to a novel situation and ascertain whether the data they obtain is confirmatory. For example, students should be able to apply a Punnett square model in genetics to identify parent genotypes and phenotypes. The reverse is also important. Students should be able to collect data and generate a model. For example, students can collect data for distance traveled over time, graph it, and develop the formula for speed.

Use this **scientific model checklist** to guide students through constructing and refining a scientific model. They can use the checklist to ensure a model is sound every time they complete a scientific investigation.

## What makes a good scientific model?

A good model is:

- based on reliable observations
- able to explain the characteristics of the observations used to formulate it
- predictive
- able to explain phenomena that were not used to develop the model
- able to be refined when new, credible, conflicting observations arise
- limited and simplifies a concept, theory, or object
- physical(2-dimensional or 3-dimensional) or
- mathematical (includes a single formula or many formulae) or
- conceptual (digital or print)
- a computer or physical simulation of a natural phenomenon