QUOTE(kenm @ Jan 19 2009, 07:01 PM)
I think of them as much the same, as the means you use to balance unity and variety. They seem to me to be names for different aspects of the same function. For example, if you asked, "What is the form of the first movement of Brahms 2?", I would probably answer, "Sonata form", but if you asked me about its structure, I would describe the three note fragment (D C# D at the beginning) that occurs frequently throughout the movement (and the other three also), in numerous versions, and the more obvious first subject, (f#- a A- d e f# e d- A), in which notes 5, 6 and 7 are a tonal inversion of the fragment, and which also returns in different versions at intervals through this movement.
Other forms are "binary", "ternary", "rondo", "theme and variations", "minuet and trio" and "scherzo and trio". The last two are pretty much the same in the large, the second having grown out of the first; nominally they differ in tempo, but Beethoven labelled the scherzo of his first symphony "Menuetto" and some of Haydn's minuets are taken pretty fast nowadays. Another difference is that a scherzo can be in simple time (e.g. Brahms 4); "scherzo" means "joke", so there is no need for it to conform to a dance rhythm.
methinks I didnt explain the question very well, I know what form is but not structure.
is it then like where the matirial comes, for example Beethovens 5th is all based on the 4 note motif at the start?
am I making any sence