QofQuimica who posts on here had a 160+ page dissertation last year.
That's a really small dissertation if that really is all that there is involved in your friend's dissertation.
I'm under the impression that they are almost like the lenth of a book.
Mine was about 215 pages total in the end (including spectra), and probably about 175 pages of my actual work.
OP, at the end of your PhD, you write up the work that you have done. This is your dissertation. Most programs require you to do enough work to publish three papers (well, that's what mine did, anyway
) The papers don't have to be actually published by the time you graduate, but you should be ready to at least submit them. (At the time I defended, I had one paper actually submitted, and I just got another published this month; god and my mentor only know when the last two will see the light of day.
). The organization of the thesis depends on your project and your area. In chemistry, some people do one huge project (ex. synthesis of a natural product) that takes them the entire time they're in grad school, and they typically organize the thesis with, say, an intro chapter, a results/discussion chapter, a chemistry/experimental chapter, a spectra chapter, and a references chapter. The intro chapter covers previous work in the field, explains the rationale for doing the work, etc. I think that the others are more or less self-explanatory.
Since I did four unrelated projects, I had four chapters, one for each project. Within each chapter, I wrote a separate intro, results/discussion (chemistry), experimental section (described how I made each compound and gave the spectral data in paragraph form to "prove" that I had really made what I thought I had made), and references. At the end, I had an appendix with all of my NMR spectra for each novel compound that I had synthesized.
The defense is a separate thing. Basically, what you do is to give a formal research seminar that lasts about 40-45 minutes. Your major professor (PI) will be there, as will your examining committee. For a PhD candidate, most committees have from 4-6 people on them. The defense is also open to the public, and so your friends, family, and other interested people can attend. At the end of the seminar, you get questioned (oral examination) by the committee. The audience is often asked to leave while the committee examines you, although my defense chair did not make them leave. Basically the committee members can ask you questions ranging from generic subject questions (i.e., explain what an amino acid is) to questions pertaining to the methodology of your research (i.e., why didn't you try reaction X when reaction Y didn't work?) to larger philosophical questions about the significance of what you've done (i.e., what do you think was the most useful thing that came out of your research?). At the end of the defense, everyone gets sent out of the room, including the PhD candidate, so that the committee can discuss whether to pass you. People almost always pass though, because usually your mentor will refuse to let you defend if s/he thinks that you won't pass.
Since defenses are open to the public, you can attend one if you're curious. Next time you see a notice posted, feel free to go. FYI, they usually serve free food.
