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10 videos · 3 h 42 min
Explainer · YouTube
The Science Asylum
Nick Lucid of The Science Asylum retells the 1922 experiment at an ideal pace for a first look, including the twist that the experimenters had detected spin years before anyone knew spin existed. As you watch, hold the classical expectation in mind, a continuous smear of deflected atoms, and ask yourself why two clean stripes were such a shock.
Explainer · YouTube
PBS Space Time
Matt O'Dowd dismantles the spinning-ball picture and follows spin into the stranger geometry underneath it, with Jason Hise's animations of objects that need two full turns to return to their starting state. A companion to this lesson's spinning-ball myth and its 720-degree electron.
Explainer · YouTube
Dr. Jorge S. Diaz
The second half of physicist Jorge Diaz's two-part history: the experiment had detected spin, and nobody saw it at first. Set it beside section 3's account, from Pauli's 'two-valuedness' to Uhlenbeck and Goudsmit, and section 2's callout on a result that was right for the wrong reason.
Explainer · YouTube
Up and Atom
Jade Tan-Holmes of Up and Atom explains quantum superposition through the Stern-Gerlach experiment: the gentlest way into section 4. Watch with the section's puzzle in mind: if an atom from a z magnet's up exit is an equal mix of +x and −x, why does an x magnet split the beam fifty-fifty, and why does the atom then forget its z answer?
Explainer · YouTube
Dr. Trefor Bazett
Mathematician Trefor Bazett opens with Dirac's belt trick, then explains it with the space of 3D rotations, modelled as a solid ball whose opposite surface points are the same rotation (3:24 and 5:31). The payoff is the 'Deforming the 4π path' chapter at 9:49: why two full turns can be undone and one cannot, as with section 6's belt and cup.
Explainer · YouTube
Looking Glass Universe
Looking Glass Universe gets her own protons' spins measured in an MRI scanner and explains how the machine uses that spin information to make an image. An easy companion to section 7's closing point: the scanner reads the smooth average of an enormous crowd of spins, yet each one, measured alone, would still answer only up or down.
Lecture · MIT
MIT OpenCourseWare
Lecture 4 of MIT's 8.05 Quantum Physics II (Fall 2013), in which Barton Zwiebach builds the machinery of spin one-half: its states and operators, the properties of the Pauli matrices, and spin states along an arbitrary direction, the general form of this session's cos²(θ/2) rule. Best watched after the lesson; it assumes the bra-ket notation of chapter 14.
Lecture · MIT
MIT Physics Instructional Resources Lab · Jerrold R. Zacharias
A 1967 college physics film featuring MIT's Jerrold Zacharias, a molecular-beam physicist who co-authored Rabi's 1938 magnetic-resonance paper. As you watch, compare the apparatus with section 2's: an oven, collimating slits, shaped magnet poles and a record of where the atoms land.
Demo · University of Göttingen
Lehrportal Uni Göttingen
A short film of the Einstein–de Haas experiment as it is presented in the University of Göttingen's Experimental Physics IV course: the effect in section 3's callout. Watch for the sample's twist when its magnetization flips, the sign that spin is real angular momentum that can be traded for the ordinary kind.
Lecture · MIT
MIT OpenCourseWare · Barton Zwiebach
A 17-minute 8.04 segment in which Barton Zwiebach treats a photon's general polarization state and spin states. Keep section 5's contrast in mind: polarization follows Malus's cos²θ, but spin odds follow cos²(θ/2), because opposite spin directions are perpendicular state arrows.