Sonata Form	More about Sonata Form	Theory Things   William Wieland
(a.k.a. Sonata Allegro Form or First Movement Form — First movements of classical works are often allegro and in sonata form.)
The Exposition establishes tonic then modulates to the dominant. Theme 1 grabs attention. It is entirely in tonic. Theme 2 is usually a lyrical contrast to the opening theme. It is in dominant. The Development freely manipulates musical ideas (keys, themes, textures, dynamics and even tempos) evoking restlessness, drama, surprise and tense expectancy. The development provides an important contrast to the more direct and stable outer sections. The Recapitulation is much like the exposition in structure. However, both themes are in tonic. The exposition is often repeated. The development and recapitulation are sometimes repeated. Introductions and codas are common. Jocelyn Swigger The Sonata Form Song   (YouTube)