The Experimental Surprise
What Stem and Gerlach found was that the atoms formed two distinct spots on the0 glass plate, one spot above the point where they would have landed with no deflection and the other spot just as far below that point. This two- spot result can be seen in the plots of which shows the outcome of a more recent version of theStem-Gerlach experiment. In that version, a beam of cesium atoms (magnetic dipoles like the silver atoms in the original Stem-Gerlach experiment) was sent through a magnetic field with a large vertical gradient dB/dz. The field could burner on and off, and a detector could be moved up and down through the beam.0 When the field was turned off, the beam was, of course, undetected and the detector recorded the central-peak pattern shown in . When the field was turned on, the original beam was split vertically by the magnetic field into two smaller beams, one beam higher than the previously undetected beam and the other beam lower. As the detector moved vertically up through these two smaller beams,
it recorded the two-peak pattern shown in .