# Model

In science, a **model** is an aid to understanding that represents an unseen or complex phenomenon.^{[1]}

Models can be empirically found, or they can be derived from fundamental laws. A good model has a well-defined domain of validity, in which it leads to unambiguous, self-consistent results. Ideally it is easy to evaluate. To adaption of a model to a specific problem instance is done by model parameters, which can be defined/measured independently or left as free parameters to fit the model to a realistic situation. A large number of free parameters makes it difficult to assess the validity of the model without independent knowledge.

One can also make a model simply by fiddling around with the data, that is, "curve fitting" without a fundamental understanding of the phenomenon, as NASA did when studying the erosion of O-rings used in the space shuttle:

- A mathematical model was made to calculate erosion. This was a model based not on physical understanding but on empirical curve fitting.
^{[2]}

## References

- ↑ Wile, Dr. Jay L.
*Exploring Creation With Biology*. Apologia Educational Ministries, Inc. 1998 - ↑ Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident