Ok, well I'm not really sure if this is the right place to post this, but I have a simple question regarding nuclear magnetic resonance. I know that the "spin" axis of a proton will align along the external magnetic field. That's pretty simple. What I don't understand is the direction they align. I'm under the impression from what I've read that approximately half will align with the field (low energy) and somewhat less will align against the field (high energy). Why do some align against the field in the first place? It seems to me that they would naturally assume the lowest energy potential. Sorry if I'm viewing this too simplistically.