what is a sonata form?

Answer 1

A form that became the standard from for the first movements of pieces in the Classical and Romantic eras. The sonata form typically includes four sections ;
Exposition : An opening section that generally presents two themes;
Development : A section that expands upon and evolves the themes of the exposition;
Recapitulation : A section that repeats the themes of the exposition unaltered ; and
Coda : A concluding section that lends resolution or a sense of finality....I hope that this helps....I been teaching classical guitar for many years !!!!!!!

Answer 2

Sonata form is a term that began to be used by theorists in the 19th century to describe a common type of piece from the classical era (and beyond). Beethoven would have never said "this piece is in sonata form."

Sonata form, as we understand it, is actually closely related to rounded binary form. It is a HARMONICALLY driven form. As the other answerers have mentioned, there are THREE main sections (exposition, development, and recapitulation). A coda is optional, as is an introduction. The exposition presents two conflicting key areas, each usually associated with a theme, or themes. If the piece is in C major, then the first tonal area will be in C major, and the second tonal area of the exposition will most likely be in G major (modulation to V). The recapitulation will repeat the musical material of the exposition, but WITHOUT the modulation to a new key. So the theme(s) that were originally presented in G major will be recapped in C major.

The development section will be characterized by harmonic instability, and will end with a prolongation of V (called a retransition).

This is skimming the surface, of course.

Charles Rosen has a wonderful book on the topic called "Sonata Forms." There's also some new research by Warren Darcy and James Hepokoski, but I haven't read it yet.

Answer 3

Sonata form was developed in the Classical period (the period of Haydn and Mozart) and was used mostly in the opening movements of symphonies and concertos (but not exclusively so). It has survived more or less intact to the present day and is still used by some composers: To summarise sonata form is as follows:

1 Exposition (I) Main theme (first subject)
2 Exposition (II) Contrasting theme in a different but related key (second subject)
3 Development (where the themes are varied, combined, turned upside down, inside out and back-to-front, just for example)
4 Recapitulation (two main subjects are restated but perhaps not exactly as in the 'exposition')
Optional 5 Coda (a short closing section which may or may not use previously presented material (but it usually does)

Sometimes the recapitulation will be quite involved, incorporating a second 'development' section.

This all looks relatively simple but was honed to a fine and sometimes complex art by composers such as Beethoven, Bruckner and Mahler.

The purpose of sonata form is to give a structure and compositional discipline to a piece of music.

Hope that helps.