Physics

Like other fields of science, physics is commonly subdivided into a number of more specific fields of research. In classical physics, those fields include mechanics, thermodynamics, sound, light and optics, and electricity and magnetism. In modern physics, some major sub-divisions include atomic, nuclear, and particle physics.

Mechanics, the oldest field of physics, is concerned with the description of motion and its causes. Thermodynamics deals with the nature of heat and its connection with work.

Sound, optics, electricity, and magnetism are all divisions of physics in which the nature and propagation of waves are important. The study of sound is also related to practical applications that can be made of this form of energy, as in radio communication and human speech. Similarly, optics deals not only with the reflection, refraction, diffraction, interference, polarization, and other properties of light, but also the ways in which these principles have practical applications in the design of tools and instruments such as telescopes and microscopes.

The study of electricity and magnetism focuses not only on the properties of particles at rest, but also on the properties of those particles in motion. Thus, the field of static electricity examines the forces that exist between charged particles at rest, while current electricity deals with the movement of electrical particles.

In the area of modern physics, nuclear and atomic physics involve the study of the atomic nucleus and its parts, with special attention to changes that take place (such as nuclear decay) in the atom. Particle and high-energy physics, on the other hand, focus on the nature of the fundamental particles of which the natural world is made. In these two fields of research, very powerful, very expensive tools, such as linear accelerators and synchrotrons ("atom-smashers") are required to carry out the necessary research.