Physics is a Greek work and in a wider sense it means science of nature. All physical phenomena has to be reproducible is one of the vital elements in physics. It is important that all the theories be established by experiments or observations as it is the initial step towards the progress of any physical theory. The next step would comprise of structuring a model or theory in order to explain the experiment or the observations. Besides producing results of the said theory a model also has to make predictions. Predictions are important to clearly grasp the model of the physical process. To conclude the theory needs to be corroborated by the experimentations offered by the model. The model will be accepted and validated only if the forecasts are correct. It is important that more experiments be directed with more precision to test the theory over and over again. In physics it is said that an experiment might be enough to quash a model and there are no fixed numbers of experiments which can verify that a theory is absolutely correct.
There is dissimilarity among models overall and fundamental concepts. Models are basic descriptions of nature whereas fundamental theories are sources on some maxims from which in principle all physical occurrences can be explained. Like, a complicated system is abridged by justified suppositions. These models play a vital role in nuclear physics where the collaboration is very complex to permit a usage by first principles.
For all situations it is important that a theorist be imaginative and intuitive as having a good imagination is more significant than being knowledgeable. It denotes the cognizance of mechanics of how the universe functions.