Michael Conte
AP Physics
Otto Stern (1888-1969)

Otto Stern
Otto Stern
Otto Stern was born and lived most of his life in Germany. His parents were Eugenie Rosenthal and Oscar Stern, who was a grain merchant. In 1912 he got his Ph.D. in physical chemistry from the University of Breslau. Then he joined Albert Einstein at the Universities of Prague and Zurich where he started becoming a professor of physical chemistry. He later became a professor in physics at the universities of Frankfurt am Main, Rostock, Hamburg, and the Carnegie Institute of Technology. Stern taught from 1913 through 1945, except for a brief military service. He moved to the United States later in 1933 because he was Jewish and the Nazis were taking over Germany. There Stern lived in Berkeley, California where he died in 1969.
Scientific Career:
Stern is most well known for his creation of a method for directing atom beams or molecules through magnetic fields to observe the magnetic moments of atoms, atomic nuclei, and protons. For this development he received the Nobel Prize in Physics in 1943. He collaborated with Walter Gerlach in the Stern-Gerlach experiment, which helped to prove some of the basic principles of quantum mechanics.
external image Stern-Gerlach_experiment.PNG


In their experiment they sent a beam of particles through an inhomogeneous magnetic field so that they were deflected. The results showed how particles have similar angular momentum to a spinning object. Treating the particle like a spinning dipole will cause the particle to precess due to the torque caused by the magnetic field. The particles trajectory is deflected because the magnetic field is inhomogeneous and the force on one end is different from the other. Instead of the particles being randomly and evenly distributed they would either be deflected up or down a specific amount. This discovery shows that spin angular momentum is quantized.
Impact of Stern’s Work:
The Stern-Gerlach experiment had a huge impact on modern physics. It tested out the Bohr model of the atom, which was the best model for the atom at the time. It helped to prove that the silver atom is quantized. Later experiments proved that other atoms were also quantized based on the Stern-Gerlach. Others used his results to make atomic clocks, hospital equipment, and quantum mechanics equations. Otto Stern was involved at Los Alamos in the Manhattan Project, giving counseling advice as a Nobel Prize winner.