more questions: is a "project" the same thing as a "movie"?
A Project is a movie you are making. You can use the clips from one or more events in a project. You can also use photos from iPhoto or Aperture or the Finder, and you can use Music from iTunes. When you "finish" a project, you use the SHARE menu to execute all your edits and create a file that can be played where you want it, in the size you want it. Even after you Share a project, you can go back and edit it some more if you like, but then you would need to Share it again.
Or is it a "project" while you create it and then it becomes a "movie:" after you finish it?
A movie is the result of your Sharing the project as I mentioned above.
This is something the Apple manual writers assume everyone already knows but I do not. What is a Cache and how it is different from a Library?
You shouldn't really need to understand caches and libraries to use iMovie. The Library is a section of your hard drive that you don't generally need to go to. It holds a bunch of files that are used by the system.
A cache is a temporary place to hold something that you might need right away. For example, Let's say you are editing the first five seconds of a clip. It takes time to go out and get the clip off the disk drive and bring it into memory so you can edit it. A cache might be used, say, to save some time by going ahead and bringing in the whole clip (not just the first 5 seconds) and maybe the next clip too. Another example. You want a glass of milk. So do you go to the store and buy a glass of milk? No. You buy a gallon of milk and put it in the refrigerator. You drink your glass of milk. When you want another glass, you go to the cache (the refrigerator) not the store. The iMovie App handles all this behind the scenes so you don't have to worry about it.
Clip seems on the surface obvious (a short section of continous video/audio that is a building block for a movie) but as I think about it, I wonder.....It is BOTH audio and video? or EITHER? If a movie contained only one clip wouold it be called a clip or a movie?
The best way to understand clips is that it is a unit of video from the time you press record on your camera until the time you press stop. Ususally a clip is from 5 seconds to 20 seconds, but if you are recording a convert, a single clip might be two hours. A clip is imported into an Event. A clip, or a portion of a clip, can be used in a project. It becomes a movie when you share the project. Could you take one clip and make a project from it with no editing? Sure.
Usually a camcorder will record both audio and video. You can, however, use only the audio or only the video in a project if you want.
If the audio and the video were from different sources would it still be a clip?
No, it would be two clips. You can edit them together. If you want to sync multiple video angles (from different cameras) and different sound sources (like really good microphones, separate from the camera) then Final Cut Pro X is your best bet. But for simple needs, you can combine audio clips and video clips in iMovie.
What are scenes? What are sections?
A scene is usually a unit within your movie. It is up to you to define that. For example, if I was makeing a movie about my daughter's marathon, I might put a scene together about the pre-race preparations, a scene about the starting line, a scene about the midpoint, and a scen at the finish line. Each scene could have many clips. A scene is really where you use your creativity. I am not sure how you are using the word Section.
What are effects?
An effect could be changing the color balance, adding a sound effect, adding slow motion or fast motion, adding an old-timey or black and white look, adding a freeze frame, there are a lot. You dont have to use them at all. It depends on the story you are trying to tell.
How many different types of panes exist? (So far, I see audio, titles, photos, transitions, effects, and iDVD) What is the difference between iDVD and DVD?
A DVD is a round disk that you put in a DVD player. You can create a DVD if you have DVD authoring software and a DVD burner. Five years ago, all Macs had DVD burners. Now, MacBook Airs, some iMacs, and some Mac Books no longer have built-in burners, but you can always add a DVD burner through a USB port. Apple used to sell iDVD, which is an app that is used for DVD Authoring. You can still find copies of iDVD on Amazon or eBay. More on disk burning here. https://discussions.apple.com/docs/DOC-3711
More and more people are shooting HD video - and DVDs are only standard definition. And more and more people are sharing the video through YouTube and Facebook, which support HD. So Apple has been deemphasizing DVD lately. They have not updated iDVD since 2006. Still, if you make movies for friends and family who are not comfortable with the internet, DVDs are still quite useful.
What is video exactly and how is video different from a movie? Does video include audio by definition? Or are there different terms to refer to video with and without audio?
I think I already answered this one.
