WHO? Stanford's Felix Bloch and Harvard's Edward Mills Purcell shared the 1952 Nobel Prize in physics "for their development of new methods for nuclear magnetic precision measurements and discoveries in connections therewith."
WHAT? Nuclear magnetic resonance (NMR) concerns atomic nuclei, which carry positive charges. Many nuclei spin on their axes and generate magnetic fields, like billions of tiny bar magnets. Slightly more than half of these nuclear magnets aim their north-seeking poles toward magnetic north (the so-called low-energy state), but the rest point in the opposite direction (high energy). If a sample is placed in a relatively strong magnetic field at a temperature above absolute zero, each spinning nucleus will wobble around its axis like a top that's been pushed sideways. The rate of this wobble is much lower than that of the spin, which can be billions of revolutions per second. The wobble, called precession, is random among spinning ...
