•   New observation or discovery is made
•   Make a HYPOTHESIS (a conjecture, a guess, an assumption).

It does not even pretend to explain everything; just one feature, one side of what was found.

•   Make new observations
•   Build a MODEL: (partial) description of the phenomenon (e.g., comet, asteroid, galaxy, quasar)

                     Model tries to explain many details.

•   Make new observations
•   Build a THEORY: a system of rules, which explain the

whole phenomenon. It can be applied for all events of the same kind. e.g. a theory, which explains motion of a comet should be used for ANY comet.

 

Science uses models to understand the Universe around us.

It holds the essence of the scientific method.

A functional model must:

- explain our observations of the real world.

- predict future observations.

For example, a model of gravity and the solar system must explain the positions of the planets in the past and predict where they will be in the future.