A(n) scientific
is a simple representation of a more complex system.

A model scientific is a simple representation of a more complex system.

Explanation:

The scientific model is a simplified representation of scientific systems that are more complex or impossible to see by the human eye, such as an atom or a solar system. Although this representation is simplified, it has the responsibility to produce all the essence, content and behavior of the original systems, thus allowing the models to be used in scientific studies and research and to promote concrete results that provide accurate information about the original systems.

your answer is "the 1950's"