In the course
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10 videos · 2 h 57 min
Explainer · YouTube
3Blue1Brown
Grant Sanderson shows that the uncertainty principle is a general fact about Fourier transforms long before it is a fact about particles: a brief sound has no crisp pitch, and Doppler radar must trade sharp range against sharp speed. The quantum chapter starts at about 10:24. Watch it beside Part 3 and the lab's wave builder.
Demo · YouTube
Veritasium
Section 1's single slit in four minutes: a laser shone through a slit that is made narrower and narrower. Watch what the spot on the screen does as the slit closes, and connect it to slit width times sideways momentum spread ≈ h. The description calls the principle a limit on measuring; section 2 sharpens that into a property of the state.
Explainer · YouTube
Sabine Hossenfelder
The jump lands on her chapter 'Is Uncertainty All About Waves?', the question this section answers with Fourier's bargain; 'What's Quantum About It?' (9:02) then asks what quantum mechanics adds. Compare her answer with the lesson's: p = ħk turns a fact about every wave into a fact about momentum. Rewind to 2:00 for what quantum uncertainty means.
Explainer · YouTube
Sixty Symbols · Michael Merrifield
Professor Michael Merrifield of the University of Nottingham on the tricky business of measuring a particle, the thought experiment at the heart of this section. Watch it with the section's warning in mind: the photon's kick illustrates the bound, it does not cause it. Sixty Symbols continues the story in 'Weak Measurement (cont. from Heisenberg's Microscope)'.
Lecture · YouTube
Fetzer Franklin Fund · Aephraim Steinberg
Aephraim Steinberg of the University of Toronto, whose group made the 2012 photon-polarization measurement this section cites, at the 2013 Emergent Quantum Mechanics symposium in Vienna, on weak measurement and uncertainty relationships. A research talk on the measurement-and-disturbance side of this section, the separate question from the bound on states.
Explainer · YouTube
Physics Explained
Exactly this section's question: why doesn't the attraction between proton and electron make the atom collapse, and what fixes its size? It sets the uncertainty-principle estimate beside a full Schrödinger-equation treatment of hydrogen's ground state, so you can see how far the rough tug-of-war argument gets you; chapter 16 does the full calculation.
Interview · YouTube
Web of Stories - Life Stories of Remarkable People · Freeman Dyson
Three minutes with Freeman Dyson on the proof that ordinary matter is stable, which he and Andrew Lenard published in 1967, and on how Elliott Lieb and Walter Thirring cleaned it up. It is the human side of this section's last paragraph, where a sharpened uncertainty inequality does the heavy lifting.
Explainer · YouTube
PBS Space Time
This section's squeezed-light story at Space Time depth: how physicists push measurements to the quantum limit by squeezing the uncertainty principle. Despite the title, the bound survives. Listen for how the noise is moved from one property of the light to its partner, not removed.
Explainer · Fermilab
Fermilab
Fermilab's Don Lincoln traces the principle to the wave nature of matter and the link between wavelength and momentum, with Fourier pictures of square and bell-shaped pulses. A good second pass on Parts 2 and 3, and on this chapter's central claim that the limit lives in the wave, not in the instruments.
Lecture · MIT
MIT OpenCourseWare · Barton Zwiebach
A ten-minute segment of MIT 8.04 (Spring 2016) that defines the Δ precisely: the standard deviation of an observable in a given state, built from expectation values. It is this section's ensemble definition on the blackboard, a property of the state rather than of any one blurry measurement.