Since 1984, the TEX system has been enhanced and extended by many packages. This document, including the HTML code, were created using some of these. The principal and most complete set of enhancements is called LATEX, written originally by Leslie Lamport and actively maintained around the world. (Truth to tell, LATEX has supplanted `raw TEX' for almost all users.) LATEX contains many features, only some of which have recently become standard in the more popular word processors. These make LATEX an appropriate tool even if you're typesetting ordinary prose or non-technical material, since it in a very flexible way can do, among other things:
(Alas: making font changes is far more difficult than it needs to be, and changes to a TEX installation can be perilous.)
Many special-purpose packages are readily included in the functionality of LATEX. For instance, as physicists, you will eventually probably use an additional macro package called REVTeX http://publish.aps.org/revtex4/. It was created by the American Institute of Physics for use in publishing journal articles and permits you to prepare and view your article in `preprint' form and even (more-or-less) as it will appear in the journal. Many journals will accept electronic journal submissions only if they are written in LATEX. Another commonly used package is AMSTeX, created by the American Mathematical Society, which adds extensive support for additional mathematical symbols. You can learn more about it at http://www.ams.org/tex. You will need to use some features of AMSTeX for your final project.