Uploads from FloatHeadPhysics

Currently Playing: I finally understand why we can’t walk through walls (My mind is blown)

Try Brilliant for free: https://brilliant.org/FloatHeadPhysics/ You'll also get 20% off an annual Premium subscription. Join my exclusive community https://www.patreon.com/Floatheadphysics to see how I learn relativity, watch exclusive videos, and get early access to youtube episodes T shirt link: https://floatheadphysics.com/products/i-dont-give-a-flux For years the answer, the Pauli exclusion principle, felt like a rule someone just made up, and I kept closing the book. In this video we build it from scratch: what happens when we swap two identical particles, why electrons have to be antisymmetric, and how that one minus sign gives us solid matter, chemistry, lasers, and the split between fermions and bosons. And at the end we see what spin has to do with all of it, with gears and a belt! Chapters 00:00 Why can't you walk through walls? 02:17 The puzzle that leads straight to the exclusion principle 05:09 The big difference between the everyday and the quantum world 07:53 The double slit and the mystery of the amplitude 18:01 What happens when two identical particles swap places? 25:09 Pauli's exclusion principle rediscovered! 29:35 Why are electrons fermions? 34:49 Why are photons bosons? 40:14 Feynman's belt trick 45:55 Putting it all together Credits The Feynman Lectures on Physics, Vol. III, Ch. 4 "Identical Particles" (Caltech online edition): https://www.feynmanlectures.caltech.edu/III_04.html R. P. Feynman, "The Reason for Antiparticles", 1986 Dirac Memorial Lecture, in "Elementary Particles and the Laws of Physics" (Cambridge University Press, 1987) Photo of Wolfgang Pauli: ETH-Bibliothek Zürich, Bildarchiv (public domain, via Wikimedia Commons) Music: "Rising Tide (faster)", "Perigrine Grandeur", "Industrial Cinematic", "Stormfront", "Hitman", "Killers", "Movement Proposition" by Kevin MacLeod (incompetech.com), licensed under Creative Commons: By Attribution 4.0 (creativecommons.org/licenses/by/4.0/) This video was sponsored by Brilliant.