Linked from
The 16 pages that link to Stern–Gerlach experiment, each with the reason it gives.
Electron spinRelated: Its two-beam result revealed discrete spin projections for silver atoms.
SpinRelated: Its split beam made spin quantization visible through measurement.
Spin quantum numberRelated: Its discrete beam splitting revealed projection quantization.
Atomic physicsRelated: The result revealed quantized angular momentum in atomic beams.
Pauli equationRelated: Its discrete beam splitting became a key clue to quantized angular momentum.
Spin-½Related: Its discrete beam splitting reveals two possible outcomes for a spin component.