What do physicists study

"A physicist is someone who studies or completes research into physics. There are many subsets of physics, ranging from very small particle physics to very large cosmology, or study of the universe. There are a wide number of physics courses and majors available. These courses are available at the undergraduate, graduate, and doctoral levels."

"What Is a Physicist? - wiseGEEK"

Physicists study natural phenomena through experiments and observational examinations, creating theories that explain how the world works. For example, physicists studied the phenomenon of gravity and came up with a generally functioning law, the law of gravity. In addition, physicists study phenomena associated with the universe, the motion and mass of objects, electricity, and various other natural phenomena.