Lesson 23: KeysKeys are a basic music concept which you will need in order to understand both chord progressions and written music. To understand this lesson, you need to know the major scales, so review Lesson 12: Major
In most songs, one particular pitch feels like the "resting" or "home" pitch; this pitch is the song's key. For example, if the pitch C feels like the home pitch, then the song is "in the key of C".
Keys can be major or minor. If a song's home pitch is C and most of the song's notes come from the C major scale, then we say the song is in the key of C major. If the song's notes come from a C minor scale, then the song is in the key of C minor.
Now let's see how you can play the same song in different keys. First, here is "Mary Had A Little Lamb" in the key of C major:
Click each note button above to hear the song.
Next, below, is "Mary Had A Little Lamb" again, this time in the key of E♭ major:
Again, click each note button.
Notice that when you play the song "Mary Had A Little Lamb" in a different key, all the pitches change, but the scale degrees stay the same. You can play "Mary" in any key by playing scale degrees 3-2-1-2-3-3-3 from that key's major scale.
When you're sure you understand how keys work, you can start learning about chord progressions in Lesson 24: Roman Numeral Chords.