The theoretical or deductive model

Einstein used this method to develop the Theory of Relativity. He began with a theory, which he imagined, and he took for granted a series of axioms or prior definitions. When he applied these axioms he obtained some results (laws) which contradicted "common sense", but which turned out to be true, when in later years they were tested with experiments designed to confirm them. 

Therefore the model is theoretical at the start but totally experimental in its verification.  

Newton also used the bases of mathematics and some axioms which he stated to develop his Theory, taking as his foundation facts studied by others, without doing any experiments personally. His theories were later totally confirmed. 

The formulas obtained by Newton allowed him to calculate positions and velocities which coincided with those of the bodies he had studied. He calculated how much the moon falls (when it separates from a straight line tangential to its trajectory) towards the Earth every second and confirmed that it coincided with what his law predicted. Once he had confirmed that his laws explained his observations perfectly and that they always applied, he made public the Law of Universal Gravitation.

This method is used less than the experimental or inductive method. 
It is called deductive because in essence it consists of stating the consequences (deducing) of a principle or supposition. 
Carry out this activity-example of how a deductive process is followed. 

Both induction and deduction are used in the processes of the two methods. When we think we continually induce and deduce.