Models are metaphorical ways of describing, predicting and understanding the natural world. They are the all-too-human, pragmatic response to the fact that we can never encapsulate the complexity and connectivity of nature in its entirety.
Scientific models are fictive simplifications with predictive power. When we run a scientific model—whether cognitively (in our heads) or mathematically (usually on a computer)—real world details that fall outside the defined parameters of the model are assumed to be irrelevant.
Models are ways of thinking. We can represent them with diagrams, formulae and three-dimensional sculptures. The representations are not the models themselves.
We might imagine a model with so many complex features that it would truly reflect and predict the entire universe; but this would be a virtual replica rather than a model since it would entail one-to-one mapping with nature itself.
Image from the Bioweb at the University of Western Kentucky
Teacher notes from Chemistry at the Georgia Perimeter College site
MORE SCIENTIFIC MODELS
The Weather Research and Forecasting Model from the Open Science Grid site.
Formula for period of swing for a simple pendulum
Feynman diagram showing electron-positron scaterring with the exchange of a photon
Electron shell configuration for Uranium 92 atom
“A catalyst is a substance, usually utilized in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process.”