• Quantum Mechanics
  • Spin
  • Quantum Measurement


The classic Stern-Gerlach Experiment shows that atoms have a property called spin. Spin is a kind of intrinsic angular momentum, which has no classical counterpart. When the z-component of the spin is measured, one always gets one of two values: spin up or spin down.

Sample Learning Goals

  • Describe the observations made in the Stern-Gerlach experiment.
  • Describe how spins behave in the presence of a magnetic field.
  • Recognize that spin is quantized.
  • Describe how measuring spin along some direction changes its state.
  • Argue from experimental observations that spin in the x direction and spin in the z direction must be incompatible observables.