The physics is not a collection of experimental data. Neither it is a collection of mathematical formulas or principles given a priori. The physics is an experimental science. Its principles are based, and supported, in the irrefutable experimental evidence. The physics is, therefore, the description and interpretation of the external world.
The external world, in the formal courses of physics, is eliminated. Even a minor mention of it is never done. The connection of the physical world and the conceptual world of the physics is never established. The student concludes his or her formal preparation believing that the physics has nothing to do with the external world.
The external world and the physics, for those scientist that understand the physics, always are inseparable. Always are together. The physicists like A. Einstein, E. Fermi, etc. always were looking to put their physical principles on the most solid experimental evidence. That is the way of working of the physicist that understand the physics. For them the external world and the physics are inseparable.
If the before mentioned concepts are understood and applied correctly, then the role of the physics is clear. Besides, the practical potentialities of the physics are clear. The physics gives a scheme that let the physicists understand the nature. And understanding the nature leads the physicists to the possibility of manipulate, to practical purposes, the nature. The mere manipulation of the nature let the physicists rectify and corroborate the physical principles. This let the physicists go deep in the understanding of nature.
The guide in the investigation of the structure of nature are very general principles. The simplicity, the beauty, the unicity, and others. Based on these principles, the physicists have proposed concepts like the atom, particles, elementary particles, etc. In practice they have proved to be very fruitful. And the physicists have constructed the actual image of the structure of the nature based on the concept of particle and force. This image coincides, in principle, with the classical Greek image. Even the actual image is more elaborated and sophisticated. It is more complex. But the ideas of simplicity, etc. are behind.
The carriers of force, particles, leptons, and quarks, are the ingredients of the scheme of the nature. There are at least six carriers, six quarks, and six leptons, and their corresponding antiparticles. These constitute the actual scheme in terms of particles and forces. This image is very far away from the Greek proposed simplicity. However, up to some level, it works. Maybe some day the Greek idea of simplicity would be obtained.
We see the partial utility of that image every day. The benefits that the physics has given to the society are many. Almost all the XX century technology is from this physics. The computation is a transcendental by-product. The computation will completely change the organization of the society of the years to come. And by itself, that change will help to modify the image about the structure of nature.
In this way, the conception of the physics as the description and interpretation of the external world is correct. It is the way the physicists that have constructed the physics understand the physics. We live the fruits of that conception every day.