Half Step and Whole Step

In Western music, the smallest interval used is the half-step. A half step means to move one note upward or one note downward. For example, let's look at the illustration above. Locate Middle C, the next key to the right of that will be a black key (C# or Db), that's a half step. Let's say you are on E, move one key up or one key to the right, that key will be F. In the same manner, if you are on Middle C, the next key to the left of that will be a white key (B or Cb), that's a half step. If you're on E and you move one key down or one key to the left, that key will be Eb or D#.