The (Often) Overlooked Experiment That Revealed the Quantum World

Before Erwin Schrödinger’s cat was simultaneously dead and alive, and before pointlike electrons washed like waves through thin slits, a somewhat lesser-known experiment lifted the veil on the bewildering beauty of the quantum world. In 1922, the German physicists Otto Stern and Walther Gerlach demonstrated that the behavior of atoms was governed by rules that defied expectations — an observation…

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