IDEAS IN PHYSICS

Ideas in Physics

Physicists spend a lot of time doing experiments and answering questions like "How are shadows formed?" In actual fact, theories have come about because the physicist first wanted to know why something behaved the way it does. The history of Physics seems to show that question, "Why?" arises at a very early stage in the investigation of new phenomena. Theories or models are then presented which hopefully represent the causes of the observed events. These theories suggest new experiments which are designed to test the theory and bring out new facts to light.




Let us consider some consepts in Physics.

Law
In Physics (and also generally in science), it is a statement that summarizes observed behaviour that can be measured. From a certain number of observations in the past, it is predicted that similar observations in the present and future will demonstrate the same facts. Note that a law is derived solely on observations made and not on preconceived theories about the behaviour of the objects being observed. Often, laws describe simple mathematical relationships between a few measurable quantities. They imply that the physical world behaves in a logical an coherent way.

Theories and models
If laws answer the question, "How?" then theories and models attempt to explain "Why?" Usually physicists speculate on the cause of observed behaviour (The : "Why?" question.) because they do not have enough knowledge to know precisely the answer. out of their intelligent guesses come imaginative pictures or models. These are exercises of the mind and only much later are they confirmed by experimentation or further observation.

The world models in Physics does not represent a scale down version of the real thing as most people understand it to be. Here, the world model is rather something which closely resembles the real thing, that often cannot be seen physically. An example is the wave nature of light. Nobody has actually seen this in action. What we have in the accepted model, is a reasonable explanation of the behaviour of light.

Some of these models are described mathematically while others have been presented in pictorial form, e.g., models of the structure of the atom. In whatever form they may be, theories and models are established with some assumtions be clear what they actually seek to represent and they should not be forced to explain what is beyond their scope.

One last world on this. When evidence is presented which contradicts a theory or model, the theory or model should be re-examined and even abandoned. This is not always easy to do as in the cases of Aristotlean an Newtonian physics. The first has been widely accepted truth for a couple of thousnd years until Newton shattered its ideas in the 17th century. When Einsten came along in the 20th century, he in turn overturned many of the concepts of Newtonian physics. So the integrity of any theory lies in its ability to stand up to all tests and evidences. The more fact that it has been accepted as authority and was proposed by eminent scientists does not excuse it from such judgements.

source : get from any source of Physics