The study of the nature and changes of objects (not involving material changes, that is, the structure of materials has not changed), that is, "things" and "principles". It is a science that studies the basic laws of nature. There are many branches, such as mechanics, electromagnetism, optics, quantum physics, heat, acoustics, fluid science, material science, kinematics, high-energy physics and so on. There are branches under sub-disciplines, especially mechanics, electromagnetism and optics. Many parts of physics are also branches of astrophysics in astronomy and its sub-disciplines, serving them.
Physics in English comes from Greek, which means nature.