The document discusses six musical elements - rhythm, pitch, dynamics, form, timbre, and texture. It then focuses on what is covered in music theory - rhythm, dynamics, melody, harmony, and form. Timbre and texture are discussed in other courses. Rhythm is defined as the regular patterns of sounds or pitches and differentiates music from noise. Melody is pitch and rhythm, usually the lead line of a song. Harmony refers to simultaneous playback of notes or melodies through chords.