Physics is the Art of finding things out. Hear Feynman talk about it:

Physics is the core of all Science, as emphatically expressed by Rutherford, deemed the greatest experimentalist since Faraday by the Encyclopædia Britannica, who famously expressed that “all science is either physics or stamp collecting”.

There is no scientific discipline, in fact hardly any discipline at all, where the concepts of motion, space, time, matter, energy, causality, information, error, etc., are not invoked, and these are what Physics is about. When applied to particular cases, Physics becomes Chemistry (the science of how matter is structured), Optics (the science of how light propagates), Astronomy (the science of celestial objects), Climatology (the science of atmosphere and oceans), Engineering (the science of implementing technology), etc. Even seemingly more remote fields such as Biology, Medicine or Geology, or more fundamental ones such as Mathematics or Computing Sciences, are deeply rooted into Physics and increasingly so as scientific expertise progresses. The field of Quantum Biology and Quantum Computation, for instance, are quickly evolving and will shape the tomorrow’s landscape of these disciplines. In a sufficiently advanced technology, everything comes back to the rule of physical laws. In this way, a computer bit becomes a qubit encoded on a bunch of few particles ruled by the principle of atomic physics, rather than by those of abstract platonic mathematics.

Physics is therefore the keystone of Science.

Some of the topics tackled by Physics:

Not part of physics per se, but related:

See also the other scales.

The American Journal of Physics

This is great material: a Physics journal that is not at a Research level, so free of the conventions and terseness required for such a format. However since Physics is intrinsically a Research topic, the content typically covers original issues.

One of the best resource of AJP is their resource letters, whose list is compiled there: AJP Resources Letters.