What is sonata form?

For the purpose of this explanation, we are looking at the Classical Sonata (where the Classical period is roughly between 1750 and 1810). Sonata form is the first movement of a sonata. This is split into three sections: exposition, development and recapitulation.The exposition introduces the main "ideas" of the piece of music. This is made up of a first and second subject. The format is as follows:First subject in tonic key --> Bridge passage ---> Second subject in dominant or relative minorAs you can tell from the name, the development takes the exposition and expands on the main ideas. This is done through several modulations.Finally, the recapitulation provides a shortened summary of the first and second subjects in the tonic key.