Unit 4 · Atoms, Spin & Identity
Chapter17
Spin & the Stern–Gerlach Experiment
A tiny magnet that refuses to point anywhere in between
Quantum Academy · presented by Dr. Quincy Quantenstein
CH 17X–Y
0:00 / 42:33OpeningTitle
Watch the lesson · Unit 4: Atoms, Spin & Identity
Spin & the Stern–Gerlach Experiment
A tiny magnet that refuses to point anywhere in between
- ≈ 43 min
- 54 scenes
- Narrated by Dr. Q
- Captions
Generated from the same script as the written lesson, so every word matches the text. Uses your device's voice when it has one; without one, the lesson plays silently with captions. Keys: Space play · ← → scenes · C captions · F full screen.
By the end you'll be able to
- Describe the 1922 Stern-Gerlach experiment and explain why two separated beams, rather than a smear, show that a component of an atom's angular momentum is quantized.
- Explain what spin is, why the electron cannot be a tiny spinning ball, and why a spin-one-half particle measured along any axis gives only +ħ/2 or −ħ/2.
- Predict the outcomes of chained Stern-Gerlach measurements, Z then Z, Z then X, and Z then X then Z, using the states |↑⟩, |↓⟩ and |+x⟩ = (1/√2)(|↑⟩ + |↓⟩).
- Calculate probabilities, expected counts and average spin components for a magnet tilted at any angle, using P(up) = cos²(θ/2).
- Explain why a 360-degree rotation reverses the sign of a spin-one-half state, and how neutron interferometers detected that sign.
- Compute magnetic resonance frequencies for electrons and protons, and explain how MRI and electron spin resonance put spin to work.