Lesson 20: KeysThis lesson explains what a musical key is. Keys are a basic music concept which you will need in order to understand both chord progressions and written music.
Before taking this lesson, you should know: major scales (Lesson 11: 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 21: Roman Numeral Chords.