In 1922, Otto Stern and Walter Gerlach shot a beam of silver atoms from a furnace through a pair of slits and then through an inhomogeneous magnetic field that deflects particles as a result of the interaction with their magnetic moments, finally landing on a photographic plate. The pattern produced consisted of two characteristic lines instead of a continuous distribution. This implies that the particles possess an intrinsic angular momentum that takes only the quantized values or , where is Planck's constant.