Thanks to Google for sponsoring a portion of this video! Support MinutePhysics on Patreon: http://www.patreon.com/minutephysics This video is about using Bohmian trajectories to visualize the wavefunctions of hydrogen orbitals, rendered in 3D using custom python code in Blender. REFERENCES A Suggested Interpretation of the Quantum Theory in Terms of "Hidden" Variables. I David Bohm, Physical Review, Vol 85 No. 2, January 15, 1952 Speakable and Unspeakable in Quantum Mechanics J. S. Bell Trajectory construction of Dirac evolution Peter Holland The de Broglie-Bohm Causal Interpretation of Quantum Mechanics and its Application to some Simple Systems by Caroline Colijn Bohmian Trajectories as the Foundation of Quantum Mechanics http://arxiv.org/abs/0912.2666v1 The Pilot-Wave Perspective on Quantum Scattering and Tunneling http://arxiv.org/abs/1210.7265v2 A Quantum Potential Description of One-Dimensional Time-Dependent Scattering From Square Barriers and Square Wells Dewdney, Foundations of Physics, VoL 12, No. 1, 1982 Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich ... https://www.youtube.com/watch?v=W2Xb2GFK2yc

The first 200 people to use http://skl.sh/minutephysics30 get 30% off a premium Skillshare subscription. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about the international system of units (SI), the international prototype kilogram (the IPK or "le grande k"), and specifically, why we need to redefine our base units in terms of fundamental constants - aka, concepts & ideas - rather than physical objects. The second is already defined in terms of a certain number of oscillations of a photon of the ground state hyperfine splitting energy of Cesium, the meter is then defined as how far light travels in a particular fraction of a second, and hopefully soon, the kilogram will be defined either using the Avogadro approach of counting silicon atoms in a sphere, or using the Watt (Kibble) Balance approach of measuring Planck's constant, h, as used in the formula E=hf for the energy of a photon, which relates to mass via Einstein's famous E=mc^2. REFERENCES: Most Recent Kilogram/Planck Constant Measurement: https://www.nist.gov/news-events/news/2017/06/new-measurement-will-help-redefine-international-unit-mass ... https://www.youtube.com/watch?v=VSrEIdhrXB4