The German-born American physicist Otto Stern (1888-1969) discovered the atomic-and molecular-beam technique and used it to provide the first direct proof of spatial quantization.

Otto Stern was born on Feb. 17, 1888, in Sorau, Upper Silesia. In 1906 he entered the University of Breslau, completing his doctoral degree in physical chemistry in 1912. He then went to the University of Prague to study under Albert Einstein and, when Einstein moved to the Swiss Federal Institute of Technology (FIT) in Zurich, Stern followed him, becoming lecturer at the FIT in 1913.

The following year Stern accepted a similar position in theoretical physics at the University of Frankfurt am Main but almost immediately found himself in military service. After the war and a brief period at the University of Berlin during 1918, Stern returned to Frankfurt. There, turning from theory to experiment, he conceived and carried out the first of the atomic-and molecular-beam experiments which brought...