I was learning about proton NMR (Nuclear Magnetic Resonance Spectroscopy) which is where protons (with their own spins) are subjected to an external magnetic field and a radio frequency is applied to flip their spin states and the re-emitted frequencies are measured.
What I don't understand is why do some protons decide to align their spins against the magnetic field [Figure 2 - some are pointing the wrong way]. This seems ridiculous atleast from the everyday experience of compasses (a compass needle always points to North).
I guess it seems weird that something would naturally assume a higher energy state. I would appreciate an explanation as to why they don't all point in the direction of the magnetic field.