Scales and modes

A scale is which of the twelve notes you use and in what order. The major scale has a fixed pattern of tones and semitones (T-T-s-T-T-T-s) that can start on any note: that is what a key is. The minor changes two degrees and with them the whole character. And the modes are the same major scale started on a different note: Dorian is C major played from D to D, and it sounds like something else although not one key is different.