What is the difference between a minor and major chord in music theory?

In Music Theory, the difference between a minor and major chord lies in the intervals between the notes. A major chord is made up of a root note, a note four semitones above the root, and a note seven semitones above the root. A minor chord is similar, but the middle note is three semitones above the root instead of four. This difference in intervals gives major chords a brighter, happier sound, while minor chords have a sadder, more melancholic quality.