Being a cello and violin teacher in Singapore, I usually get some sort of answer like “Major sounds joyful, and minor sounds gloomy.” Well, this is partly correct in that sense! I would like to break it down to a more simple form though.
Alvin from Strings Singapore spell out to us that the difference between major and minor chords and scales boils down to a difference of one essential note – the 3rd. The 3rd is what gives major-sounding scales their more cheerful sound, and what gives minor scales their gloomier sound.
All major scales have the same pattern. I believe at some point of time, you have heard or sang Do-Re-Mi-Fa-So-La-Ti-Do. If you don’t, check out the video below for the childhood classic: