This may seem a vague topic but I just like to enquire in general about how standard/conventional physics is done and how to produce correct physics. On the definition of physics, Wikipedia has 'Physics attempts to describe the natural world by the application of the scientific method.' So it is intrinsically a theoretical endeavour (whereas I would call Engineering an intrinsically pratical endeavour). The goal is to produce correct physical theories which must be confirmed by experimentation. Note: Correct here refers to what is accepted in the physics community because one cannot be correct about a physical theory as one can be correct about 1+1=2. http://en.wikipedia.org/wiki/Physics http://en.wikipedia.org/wiki/Engineering 1. One start with very simple observation like apple falling to the ground or passing current through a wire and see a compass needle move. 2. Form definitions which could accurately as possible describe and distinguish these phenomena. 3. Do some controlled experiments involving the items that have been defined. And find relationships between them, in terms of numerical data in terms of clearly defined units. 4. Form precise as possible although never perfect theoretical relationships between these definitions by matching it with experimental data. 5. Use available theoretical methods to make deductions if possible from the established theory. Hence make it more elegant, complete and also find some new relationships if possible like Maxwell finding EM waves travel at speed c so EM is light. 6. The theory is rendered correct. After that physicists may dream up an experiment that involve physical entities that already have precise theoretical relationships. They can use these theories to guide what they want to do in their experiment. i.e. in their experiment they recquire the electrons to bend in a circle in order to find the charge to mass ratio of the electron. They can use the relavant formulae (which was established correct through prior experimentation) and put the paramaters of the current experimental situation into the formulae to find the charge to mass ratio. So the process is finding fundalmental theories then using it in more complex experiments to find newer and more complex relationships. Or it could be finding fundalmental physical entities/relationships in a different way as a result of a new theory such as determining the speed of light from EM theory. And hopefully, confirming the quanitity (if a contradiction or large error (not due to experimental error) is found than there is something wrong somewhere, which could be very bad because prior experiments that used the wrong theory in parts of the experiment would have got a wrong final result). In this way, theory and experiment are very much interlinked. Physics starts off empirically and after that theory and experiment are very much interlinked. Sometimes one can get ahead of the other but both are needed to prodce correct physics. i.e. GR was formulated before any direct experimental data although it had SR as a grounding which was backed by solid experimental data. It was only after people were able to test it did such as Eddington could GR be stated as a correct theory.