The first 200 people to go to http://brilliant.org/minutephysics get 20% off a premium subscription to Brilliant. This video is about Bell's Spaceship Paradox of Special Relativity, wherein a pair of rockets (or spacecraft) connected by a weak thread accelerate with uniform acceleration, maintaining the same separation, and the question is: does the thread break? And if so, why? REFERENCES Interactive Spacetime Globe by Alexander Wu: https://alexonscience.com/projects/spacetimeglobe/ Read an overview on Wikipedia: https://en.wikipedia.org/wiki/Bell%27s_spaceship_paradox John Baez on Bell's Spaceship Paradox, Rindler Acceleration, etc https://math.ucr.edu/home/baez/physics/Relativity/SR/BellSpaceships/spaceship_puzzle.html Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics 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

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

Watch the bonus material cut from this video and get 26% off an annual subscription to CuriosityStream and Nebula at https://www.curiositystream.com/minutephysics The Solution to the Windmill Paradox. This video is about the tradeoff of Windmills: the fact that the more kinetic energy you extract from the wind the slower the wind goes, the less wind you have to extract energy from, etc. How much energy is the sweet spot to extract from the wind?? Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics 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

Go to https://curiositystream.com/minutephysics to get access to CuriosityStream AND Nebula (where you can watch the extended version of this video), plus you'll get a 26% discount on an annual subscription. This video is about the "Kelvin wake" shape of water wakes behind boats - we talk about mach angle, dispersion, superposition of many waves, and how these all lead to the pattern of a wake. We don't get into Froude number though... REFERENCES Boat Wake Wikipedia Page: https://en.wikipedia.org/wiki/Wake Interactive Boat Wake Simulation: https://observablehq.com/@rreusser/dispersion-in-water-surface-waves Feynman Lectures on Water Waves: https://www.feynmanlectures.caltech.edu/I_51.html#Ch51-S4 Building up a Boat Wake from V-Shaped Wakes: https://editor.p5js.org/aatish/full/bDiykicsC Wave Dispersion: https://en.wikipedia.org/wiki/Dispersion_relation Mach angle shock waves: https://www.sciencedirect.com/topics/engineering/mach-angle Ship Wakes - Kelvin or Mach Angle? Rabaud and Moisy Paper: https://j

This video was created in partnership with Bill Gates, inspired by his new book “How to Avoid a Climate Disaster.” Find out more here: https://gatesnot.es/3u7UUVU This video is about how physics dictates the design of modern windmills - why they are so big, have so few blades, and have such skinny blades. REFERENCES H. Glauert: Aerodynamic Theory, 1935 Division L (Airplane Propellers), Chapter XI: Windmills and Fans Wind power extraction fundamentals https://home.uni-leipzig.de/energy/energy-fundamentals/15.htm Betz's Law https://en.wikipedia.org/wiki/Betz%27s_law Tip Speed Ratio https://en.wikipedia.org/wiki/Tip-speed_ratio Aerodynamics of Wind Turbines Book https://www.amazon.com/Aerodynamics-Wind-Turbines-Physical-Analysis/dp/1119405610 Penn State Wind Turbine Aerodynamics Lesson https://www.e-education.psu.edu/aersp583/node/469 Wind Power Physics youtube video https://www.youtube.com/watch?v=qx_M0nvDIGU Why do Wind Turbines Have Three Blades? https://rosemary-barnes.medium.com/why-do-wind-turbine

Go to https://curiositystream.com/minutephysics get access to CuriosityStream AND Nebula (where you can watch the extended version of this video), plus you'll get a 26% discount on an annual subscription. This video covers the General theory of Relativity, developed by Albert Einstein, from basic simple levels (it's gravity, curved space) through to the concepts of how curved spacetime is represented by psuedo-Riemannian manifolds with Lorentzian signature (that is, special relativity and minkowski space are the local tangent space), how matter and energy are represented by an energy-momentum tensor, and how these two together obey the Einstein Field Equations. The solutions to the Einstein Field Equations (including the schwarzschild metric, kerr metric, freedman-lemaitre-robertson-walker metric, etc) represent gravity around massive objects like the sun, earth, and black holes, but also the history and expansion and future evolution of the cosmos. The universe on a large scale is described by general relat

Thanks to Brilliant for sponsoring this video - the first 200 people to click on https://www.brilliant.org/MinutePhysics will get 20% off a Premium subscription to Brilliant. This video written & produced in collaboration with Aatish Bhatia, https://www.aatishb.com This video is about how cheap, fast, and LESS sensitive rapid antigen tests might be better for screening (& maybe surveillance) than PCR COVID tests due to the nature of contagiousness/infectiveness at various points on the viral load trajectory of symptomatic and asymptomatic COVID sars-COV-2 carriers. REFERENCES Thanks to Daniel Larremore for feedback on early versions of this video https://larremorelab.github.io/ Rapid Antigen Testing: COVID-19 testing: One size does not fit all. https://science.sciencemag.org/content/371/6525/126 Rethinking Covid-19 Test Sensitivity — A Strategy for Containment. https://www.nejm.org/doi/full/10.1056/NEJMp2025631 Test sensitivity is secondary to frequency and turnaround time for COVID-19 screening. http

Thanks to the Heising-Simons foundation for their support: https://www.hsfoundation.org (their COVID-19 grants: https://www.hsfoundation.org/grants/covid-19-response-grants/ ) Check out https://aatishb.com/maskmath to explore and for references. This video is about how masks (whether surgical, or N95, or cloth) are counterintuitive and actually work much better epidemiologically than one might expect. Masks do double-duty, and the fraction of interactions with masks is much higher than the fraction of people wearing masks, so partially adopted, partially effective masks are able to reduce the basic reproduction number surprisingly well. REFERENCES: Aatish’s detailed writeup on github: https://github.com/aatishb/maskmath/blob/master/model/mathmodel.ipynb Amid the Coronavirus Crisis, a Regimen for Re-entry: https://www.newyorker.com/science/medical-dispatch/amid-the-coronavirus-crisis-a-regimen-for-reentry Face Masks Against COVID-19: An Evidence Review https://www.preprints.org/manuscript/202004.0203/v3

Head to https://brilliant.org/MinutePhysics to sign up for free and get 20% off a Premium subscription to Brilliant! This video was written in collaboration with Aatish Bhatia - https://aatishb.com To learn more about using & decontaminating N95 masks: https://www.n95decon.org Thanks to Manu Prakash for useful discussion and feedback (Manu is involved with the N95 decontamination project) Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ The physics & engineering of N95 mask design is pretty incredible. REFERENCES 10X efficiency of electrically charged fibers "The electrostatic charge of N95 masks is a major contributor to their filtration efficiency, improving it at least 10-fold over uncharged fabric" (Tsai et al., Journal of Electrostatics 2002; Peter Tsai, personal communication). Prakash Lab COVID-19 Response Group Working Draft Document on N95 masks: https://docs.google.com/document/d/1aACcbkyZjR7nZy_w

This video made possible with support of Brilliant - the first 200 subscribers to go to http://Brilliant.org/MinutePhysics get 20% off a Premium subscription to Brilliant. Go to http://aatishb.com/covidtrends to explore the graph from the video yourself! RESOURCES Grant's 3Blue1Brown Video: Exponential Growth and Epidemics: https://www.youtube.com/watch?v=Kas0tIxDvrg Aatish's Exponential/Logistic Curve-Fitting Site: https://github.com/aatishb/covid/blob/master/curvefit.ipynb Data Source: https://github.com/CSSEGISandData/COVID-19 Our World in Data Page on Coronavirus: https://ourworldindata.org/coronavirus How many tests for COVID-19 are being performed around the world? https://ourworldindata.org/covid-testing Understanding logarithmic scales: https://www.nytimes.com/2020/03/20/health/coronavirus-data-logarithm-chart.html What we can learn from the countries winning the coronavirus fight: https://www.abc.net.au/news/2020-03-26/coronavirus-covid19-global-spread-data-explained/12089028 (Great explainer

This video was made with the support of the Heising Simons Foundation. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about the Ozma problem of distinguishing the chirality (ie left-handedness or right-handedness) of matter using weak interaction processes like beta decay (for example in uranium), or neutral kaon/k-meson decay. This is wrapped up in the phenomenon of CP violation, by which charge and parity are both violated by certain weak interaction processes - this enables antimatter to be unambiguously distinguished from matter, and left handed chirality from right handed. REFERENCES The Ozma Search for Extraterrestrial Intelligence (SETI) Project https://www.seti.org/seti-institute/project/details/early-seti-project-ozma-arecibo-message Sean Carroll on CP Symmetry (& why we shouldn’t trot out baryogenesis all the time) https://www.preposterousuniverse.com/blog/2010/06/04/marketing-cp-violat

Go to https://Brilliant.org/MinutePhysics to gift Brilliant Premium for the holidays, and for 20% off! This video is about cutting, taping, and rearranging the periodic table into the Left Step form, the Mendeleev's flower form, the cake form, the wide form, the standard form, and so on. A great holiday craft!! REFERENCES Alternate Periodic Tables https://en.wikipedia.org/wiki/Alternative_periodic_tables Electronegativity https://en.wikipedia.org/wiki/Electronegativity Atomic Radius Radii https://en.wikipedia.org/wiki/Atomic_radius First Ionization energy https://en.wikipedia.org/wiki/Ionization_energy Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics --

Go to https://curiositystream.com/minutephysics to check out MinuteBody, and for a free month of CuriosityStream PLUS Nebula! Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about why words flip left & right (aka horizontally) in a mirror but not up & down (aka vertically). The answer has to do with specular reflection, mirrors being like windows into another world (alternate universes, just with in and out flipped!), and transparency of the things we write on. REFERENCES Specular Reflection https://en.wikipedia.org/wiki/Specular_reflection PhysicsGirl video about mirrors https://www.youtube.com/watch?v=vBpxhfBlVLU Fermat’s principle http://electron6.phys.utk.edu/optics421/modules/m1/Fermat's%20principle.htm Thomas-Fermi screening https://en.wikipedia.org/wiki/Thomas%E2%80%93Fermi_screening MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (

Thanks to CuriosityStream for their support. Go to http://www.curiositystream.com/minutephysics to watch Particle Fever and get Nebula! Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about two-photon (gamma-gamma) physics, and how photons can interact with each other - either mediated by a passing lepton, or gravitationally via lensing, or via vacuum fluctuation pair production of vertical particles (electron-positron pair, for example). This is the so-called "box diagram" feynman diagram. REFERENCES Water waves interact with each other (weakly nonlinear shallow water waves) https://en.wikipedia.org/wiki/Korteweg%E2%80%93deVriesequation http://mathworld.wolfram.com/Korteweg-deVriesEquation.html Paper: Absorption of Very High Energy Gamma Rays in the Milky Way https://arxiv.org/pdf/1608.01587.pdf Paper: Observing light-by-light scattering at the Large Hadron Collider (LHC) https://arxiv.org/pdf/130

Sign up for Brilliant FOR FREE at http://brilliant.org/minutephysics - the first 200 people get 20% of a premium subscription. This video is about how Russian physicist Aleksandr Fridman corrected Albert Einstein about the expansion of the universe. Einstein thought that general relativity implied that space had to be static and unchanging, but he had made a technical error regarding the differentiation of the metric (in particular, I believe he mistook the determinant of the metric for a scalar rather than a tensor density of weight 2). Friedmann didn't make this differential geometric mistake, and the cosmologies he found from the Einstein Equations were more varied in their properties - they could be expanding, or contracting, or (with the cosmological constant), static. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ REFERENCES Alexander Friedmann https://en.wikipedia.org/wiki/Alexander_Friedmann Einstein Wron

Go to http://www.dashlane.com/minutephysics for a free 30 day trial and 10% discount with offer code 'minutephysics' Watch the main video here: https://www.youtube.com/watch?v=pT19VwBAqKA Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ REFERENCES Cynthia Dwork (key inventor of Differential Privacy), giving a great intro talk about differential privacy https://www.youtube.com/watch?v=lg-VhHlztqo Hazards of Smoking: the Effect on Life Span https://www.nejm.org/doi/pdf/10.1056/NEJMsa1211128 NHL Hockey Birth distributions https://www.quanthockey.com/nhl/birth-month-totals/nhl-players-career-stats.html MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich

This video was made in collaboration with the US Census Bureau and fact-checked by Census Bureau scientists. Any opinions and errors are my own. For more information, visit https://census.gov/about/policies/privacy/statistical_safeguards.html or search "differential privacy" at http://census.gov. REFERENCES Differential Privacy in the Wild: http://www.vldb.org/pvldb/vol9/p1611-machanavajjhala.pdf Harvard University Privacy Tools Project: https://privacytools.seas.harvard.edu/differential-privacy Simons Institute Workshop Video Recordings and Articles Archive: https://simons.berkeley.edu/workshops/schedule/6281 Cynthia Dwork (key inventor of Differential Privacy), giving a great intro talk about differential privacy: https://www.youtube.com/watch?v=lg-VhHlztqo Shiva P Kasiviswanathan and Adam Smith. On the semantics of differential privacy: A Bayesian formulation. Journal of Privacy and Confidentiality, 6(1):1–16, 2014. Shiva Prasad Kasiviswanathan and Adam Smith. On the ‘semantics’ of differential priva

Where to Buy "How To" by Randall Munroe: · PRH.com: https://bit.ly/2L2G5hy · Amazon: https://bit.ly/2zfy974 · Barnes and Noble: https://bit.ly/2Zozxmt · IndieBound: https://bit.ly/2ZfwSre · Books-A-Million: https://bit.ly/2ZfxD3y · Apple Books: https://bit.ly/33TK3kX The world's most entertaining and useless self-help guide, from the brilliant mind behind the wildly popular webcomic xkcd and the #1 New York Times bestsellers What If? and Thing Explainer For any task you might want to do, there's a right way, a wrong way, and a way so monumentally complex, excessive, and inadvisable that no one would ever try it. How To is a guide to the third kind of approach. It's full of highly impractical advice for everything from landing a plane to digging a hole. Bestselling author and cartoonist Randall Munroe explains how to predict the weather by analyzing the pixels of your Facebook photos. He teaches you how to tell if you're a baby boomer or a 90's kid by measuri

Check out the "What is a Day?" interactive video at https://labs.minutelabs.io/what-is-a-day/ It's super cool!! (and made by Jasper Palfree & the MinuteEarth/MinutePhysics team) The MinutePhysics video about Why December Has the Longest Days: https://www.youtube.com/watch?v=nZMMuv0Ltyo This video is about the length of a solar day vs a stellar day vs a mean standard day, what they all have to do with each other and the earth's orbit, eccentricity, axial tilt, and so on. Also, aliens and asteroids. It'll explain the equation of time, and why the longest day is in December. The lab will also show you what days are like on all the other planets - Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and even - though it's not a planet - Pluto. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this

Thanks to Brilliant for supporting MinutePhysics. Get 20% off a premium subscription at https://www.Brilliant.org/minutephysics This video is about how Albert Einstein made a mistake when applying the Field Equations of General Relativity to cosmology (in particular, to a static, constant density universe), and solved the problem by introducing the cosmological constant, rather than allowing for a dynamic universe with a scale factor - that is, the Friedmann-Lemaitre-Robertson-Walker universe, first developed by Alexander Friedmann of Russia. Later, it was discovered by the Slipher and Hubble red-shift that the universe is indeed expanding, and even later, by Schwarz and company in 1998, that the expansion is accelerating - aka, dark energy. And the cosmological constant was re-introduced. REFERENCES The Einstein Field Equations https://en.wikipedia.org/wiki/Einstein_field_equations Interrogating the Legend of Einstein’s “Biggest Blunder” https://arxiv.org/abs/1804.06768 On the General Theory of Relativi

Thanks to CuriosityStream for supporting this video. Head to http://curiositystream.com/minutephysics and use promo code minutephysics for 30 days FREE! This video is about the Portal Paradox - a paradox in the video game Portal (and Portal 2) regarding whether or not a companion cube passing through a moving portal plops out of the other end with no speed (velocity, momentum), or shoots out at high speed. It’s a question of conservation of momentum, relativity of velocities, wormholes, 3D printers and quantum teleportation, glitches, and more. REFERENCES Conservation of momentum https://en.wikipedia.org/wiki/Momentum#Conservation_in_a_continuum Principle of Locality https://en.wikipedia.org/wiki/Principle_of_locality YouTube video of testing the Portal 2 game engine on the portal Paradox https://youtu.be/S85nudR6D-Y Tutorial for how to program the Portal portals on your own: https://www.gamasutra.com/view/feature/132164/games_demystified_portal.php Support MinutePhysics on Patreon! http://www.patreo

Thanks to the Heising Simons Foundation (https://www.hsfoundation.org/) for their support of this video, and of short range gravity research. This video is about how little we know about the behavior of gravity at short length and distance scales, what the constraints are on the inverse square law/Newton's law of universal gravitation, at the human and microscopic and atomic scales. Only on solar system scales or larger do we have good constraints on Newton's law of gravitation. REFERENCES Review of short-range gravity experiments in the LHC era https://arxiv.org/abs/1408.3588v2 Zeptonewton force sensing with nanospheres in an optical lattice https://arxiv.org/abs/1603.02122 Large extra dimensions https://en.wikipedia.org/wiki/Large_extra_dimension Search for Screened Interactions Associated with Dark Energy Below the 100 μm Length Scale https://arxiv.org/abs/1604.04908 Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale https://arxiv.org/abs/hep-ph/0611184v1 Photon Mass E

Thanks to Brilliant for supporting this video! The first 200 people to go to https://brilliant.org/MinutePhysics will get 20% off a premium subscription to Brilliant. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics This video is about how I designed and made my own custom mute guitar pedal for my clip-on mic and piezo pickup on my violin (fiddle). The mic is an AT Pro35 phantom powered XLR condensor microphone, and the pickup is a Fishman V200 piezoelectric transducer. I got all of the parts from PartsExpress. Thanks to my band (https://www.youtube.com/channel/UCEKRoVVSZKGih6v_xK4LAdw), Caleb, Pete, Paul and Troy, and to Hannah for filming. Link to Patreon Supporters: http://www.minutephysics.com/supporters/ REFERENCES: Gearslutz mute wiring for phantom powered vs dynamic/line-level microphones: https://www.gearslutz.com/board/geekslutz-forum/813680-how-wire-external-xlr-off-switch-pedal.html Beavis Audio Research: http://beavisaudio.com/techpages/ Pickups on wikipedia: https://

Go to http://www.dashlane.com/minutephysics to download Dashlane for free, and use offer code minutephysics for 10% off Dashlane Premium! Watch the main video: https://www.youtube.com/watch?v=lvTqbM5Dq4Q Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics This video explains how Shor’s Algorithm factors the pseudoprime number 314191 into its prime factors using a quantum computer. The quantum computation relies on the number-theoretic analysis of the factoring problem via modular arithmetic mod N (where N is the number to be factored), and finding the order or period of a random coprime number mod N. The exponential speedup comes in part from the use of the quantum fast fourier transform which achieves interference among frequencies that are not related to the period (period-finding is the goal of the QFT FFT). REFERENCES RSA Numbers (sample large numbers to try factoring) https://en.wikipedia.org/wiki/RSA_numbers IBM on RSA https://www.ibm.com/support/knowledgecenter/en/SSB23S1.1.0.13

Go to http://www.dashlane.com/minutephysics to download Dashlane for free, and use offer code minutephysics for 10% off Dashlane Premium! Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics This video explains Shor’s Algorithm, a way to efficiently factor large pseudoprime integers into their prime factors using a quantum computer. The quantum computation relies on the number-theoretic analysis of the factoring problem via modular arithmetic mod N (where N is the number to be factored), and finding the order or period of a random coprime number mod N. The exponential speedup comes in part from the use of the quantum fast fourier transform which achieves interference among frequencies that are not related to the period (period-finding is the goal of the QFT FFT). Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minut

Thanks to http://brilliant.org/minutephysics for supporting MinutePhysics - get 20% a premium subscription at http://brilliant.org/minutephysics Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about compressed air cans (aka gas dusters) and why they get cold when you spray them. They cool off because the refrigerant inside (1,1-difluoroethane) is under pressure and boils off when the pressure lowers, and energy lost to the latent heat of vaporization cools the can a lot. Difluoroethane normally boils at -25°C (-13°F), but under ~6 atm (6 bar, 600 kpa) it is a liquid at room temperature. The gas also cools off slightly due to the Joule-Thompson effect of fluid expansion through a throttled valve. Difluoroethane is heavier than air and water soluble, so it is recommended to use it in a ventilated environment to clean your keyboard, etc. Also, 1,1-difluoroethane is a potent greenhouse gas. It is also known

Get a free trial of Audible at https://audible.com/minutephysics or by texting 'minutephysics' to 500500 Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics This joke video is about how Internet Service Providers (aka ISPs, internet companies, telecommunications companies, etc) violate the basic axioms of Zermelo-Fraenkel set theory. Like the axiom of choice (sometimes Well-ordering theorem), the Axiom of extensionality, Axiom of regularity (also called the Axiom of foundation), Axiom schema of specification, Axiom of pairing, Axiom of union, Axiom schema of replacement, Axiom of infinity, Axiom of power set. Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich

Thanks to @AstroKatie (http://astrokatie.com, http://twitter.com/astrokatie) for the collaboration! Go to http://www.brilliant.org/minutephysics for free daily science puzzles Here's the original twitter thread https://twitter.com/astrokatie/status/1066526148149108736 Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about the cosmic distance scale and how we see objects farther away in space (ie at higher red shift) farther back in time because light takes time to reach us. Thus we can see not only stars and galaxies, but also the primordial stars & proto-galaxies, and even the remnants of the beginning of the universe itself: the CMB cosmic microwave background left over from the big bang. 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! Cre

To keep your brain sharp with quick daily math & science puzzles, head to http://www.brilliant.org/minutephysics This video is about how to create muons in a particle accelerator via bombardment of heavy nuclei with protons, which results in creation of charged pions (plus and minus). The pions then decay into muons and mu neutrinos, and the muons then decay into electrons or positrons and more neutrinos. Muons also form in the upper atmosphere due to cosmic rays, and the uses of muons includes experimental tests of time dilation in special relativity, catalyzing muonic cold nuclear fusion, and more. Muons on wikipedia: https://en.wikipedia.org/wiki/Muon Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining

Need a last minute holiday gift idea? Go to https://www.brilliant.org/minutephysics for 20% off a premium subscription to Brilliant (can be given as a gift). Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 This video is about Hardy's Paradox, wherein an electron and positron (or photons polarized horizontally and vertically) pass through Mach-Zehnder interferometers that overlap such that the particles have a chance of annihilating. If they do annihilate, then the interference pattern changes and there is a probability for both particles to be detected in the "dark arms" of the detector, that is, where previously there was no probability for detection for either particle. The paradox has implications for local realism, contextuality, lorentz elements of rea

Thanks to Brilliant.org for supporting MinutePhysics! The first 200 people who go to http://www.brilliant.org/minutephysics will get 20% off a Premium Subscription to Brilliant. This video is about how terrestrial muons are part of our experimental proof of time dilation, length contraction, and special relativity in general. REFERENCES Cosmic Rays https://en.wikipedia.org/wiki/Cosmic_ray Terrestrial Cosmic Rays http://people.physics.tamu.edu/wwu/docs/P225/P225_Project_terrestrial%20cosmic%20rays.pdf Cosmic Ray Interaction Depth & Muon Production Altitude http://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Interaction.htm Cosmic rays are stronger at the poles http://www.antarcticglaciers.org/glacial-geology/dating-glacial-sediments-2/cosmic-rays/ Cosmic Rays on Hyperphysics http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/cosmic.html Exponential decay and mean lifetime https://en.wikipedia.org/wiki/Exponential_decay#Mean_lifetime Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to

Thanks to Brilliant.org for supporting MinutePhysics - the first 200 people to go to http://www.brilliant.org/minutephysics will get 20% off of a premium subscription to all of Brilliant's courses and puzzles. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about the original cold fusion: μ muon-catalyzed cold fusion of deuterium, tritium, hydrogen, into helium-3 and helium 4. The problems with it are the half-life of muons and the sticking of muons to alpha particles. Also involved are neutrons, protons, break-even, etc. This has nothing to do with fusion by capture in palladium electrodes. REFERENCES: The original papers: L.W. Alvarez 1957, F.C. Frank 1947, and J.D. Jackson 1957 A History of Muon Catalyzed “Cold” Fusion http://large.stanford.edu/courses/2016/ph241/yoon1/ Fusion rates http://www.kayelaby.npl.co.uk/atomic_and_nuclear_physics/4_7/4_7_4.html Cold Fusion https://en.wikipedia.org/wiki/

Thanks to LEGO for sponsoring this video. Find your own LEGOs at https://shop.lego.com/?cmp=SOC-OneMinutePhysics or https://shop.lego.com/product?p=21309&cmp=SOC-OneMinutePhysics This video is about Tuned Mass Dampers, which can be used to reduce or avoid unwanted vibrations, swaying, swinging, bending, etc on engineered structures ranging from buildings, skyscrapers, electricity power transmission lines, airplane engines, formula one race cars, etc. TMD's use damped coupled oscillators. REFERENCES Taipei Tower TMD Photo licensed from: Louie Psihoyos http://www.psihoyos.com Coupled oscillators: http://www.reed.edu/physics/faculty/wheeler/documents/Sophmore%20Class%20Notes%202007/Chapter%204.pdf Related things: https://en.wikipedia.org/wiki/Stockbridge_damper Applications: https://en.wikipedia.org/wiki/Tuned_mass_damper#Mass_dampers_in_automobiles Formula 1 cars: http://www.formula1-dictionary.net/mass_damper.html Aircraft engines: https://en.wikipedia.org/wiki/Centrifugal_pendulum_absorber Audio speaker co

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober This video is chapter 8 in my series on special relativity, and it presents a hands-on explanation of the resolution to the Twins Paradox using the mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Of course, the Twins paradox can be resolved with an understanding of spacetime intervals, relative inertial frames of reference, etc, but this is a nice hands-on version where you actually measure the proper times on a real, physical spacetime diagram with a ruler. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining vie

Watch the original video in Spanish here: https://www.youtube.com/watch?v=J2Vkv5GQXww This video is about how the physics and chemistry of sugar (in particular, how it melts, and how it caramelizes) is more complicated than you might think. It involves fructose, sucrose, glucose, and a sticky mess. Credits: Gallium melting footage by WorkshopScience https://www.youtube.com/watch?v=jow4idr6HNs Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich

Check out Grant’s channel: 3blue1brown: https://www.youtube.com/3blue1brown This video recounts a lecture by Richard Feynman giving an elementary demonstration of why planets orbit in ellipses. See the excellent book by Judith and David Goodstein, "Feynman's lost lecture”, for the full story behind this lecture, and a deeper dive into its content. Tweet referenced at the start: https://twitter.com/3blue1brown/status/1016936129117937664 Music by Nathaniel Schroeder: https://soundcloud.com/drschroeder/elizabeth-the-mouse Music by Vincent Rubinetti: https://soundcloud.com/vincerubinetti/one-two-zeta Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minu

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober This video is chapter 7 in my series on special relativity, and it covers the idea that some things AREN'T relative: there IS a sense of absolute length and absolute time, which can be agreed upon from all moving perspectives (as long as they're inertial reference frames). In particular, proper length and proper time, aka the spacetime interval. Essentially, this is the spacetime version of the pythagorean theorem, and we'll explore it using the Lorentz transformations of lengths and time intervals, enacted with a mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyo

Thanks to the James Webb Space Telescope (JWST) and Space Telescope Science Institute for supporting this video. This video is about the cycloid curves on Jupiter's moon Europa - they're ridges or valleys in the icy surface that formed due to some sort of geological or tectonic-esque phenomenon. The answer involves ping pong balls, the pacific ring of fire, subduction, tidal bulges, and tailcracking, REFERENCES Europa image: https://upload.wikimedia.org/wikipedia/commons/8/82/PIA19048_realistic_color_Europa_mosaic.jpg Europa “google maps” explorere: https://www.mapaplanet.org/explorer-bin/explorer.cgi?map=Europa&layers=europa_galileo_bw&west=180&south=-90&east=-180&north=90&center_lat=0&center=0&defaultcenter=on&grid=none&stretch=none&projection=SIMP&advoption=NO&info=NO&resolution=2 Cycloid: https://en.wikipedia.org/wiki/Cycloid Formation of Europa cycloid cracks: http://pirlwww.lpl.arizona.edu/HIIPS/Publications/hoppa_abstracts/cycloid.html Smashed ping pong ball: https://www.researchgate.net/figure/

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober This video is chapter 6 in my series on special relativity, and it covers the topic of relativistic addition of velocity: aka, how things that are moving relative to one inertial reference frame, which is moving relative to another reference frame, what speed or velocity are those things moving relative to the second frame. We'll show this using the Lorentz transformation of moving worldlines, enacted with a mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober This video is chapter 5 in my series on special relativity, and it covers how things that are moving (that is, moving relative to an inertial reference frame) at different speeds appear to be shorter in length... and longer in length. And shorter in time, and longer in time. It all makes sense, I promise, and is clear when you use the Lorentz transformation of coordinates of the events in question, enacted with a mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining v

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober The previous videos in this series: Chapter 1: Why Relativity is Hard https://www.youtube.com/watch?v=1rLWVZVWfdY& Chapter 2: Spacetime Diagrams https://www.youtube.com/watch?v=hTxWAQGgeQw Chapter 3: Lorentz Transformations https://www.youtube.com/watch?v=Rh0pYtQG5wI This video is chapter 4 in my series on special relativity, and it covers how things that appear simultaneous from one perspective in our universe aren't simultaneous from other moving perspectives - that is, from inertial reference frames moving at different speeds. This is explained via the Lorentz transformation of coordinates of the events in question, enacted with a mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/suppor

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober The previous videos in this series: Chapter 1: Why Relativity is Hard https://www.youtube.com/watch?v=1rLWVZVWfdY& Chapter 2: Spacetime Diagrams https://www.youtube.com/watch?v=hTxWAQGgeQw This video is chapter 3 in my series on special relativity, and it covers boosts, galilean transformations, newtonian relativity, and of course Lorentz transformations, the constancy of the speed of light, relative changes of velocity between inertial reference frames, etc - some of the stuff Einstein figured out. I introduce the mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does an

Thanks to NASA's James Webb Space Telescope (JWST) project and the Space Telescope Science Institute for supporting this video. This video is about the line between Brown dwarfs and gas giant planets (aka super Jupiter's): does it exist? Is it the deuterium-burning threshold? Behavior? Metallicity? Formation? Or is there no meaningful scientific distinction, and are brown dwarfs and giant planets really all on a spectrum with no clear line between them? REFERENCES Giant planet and brown dwarf formation https://arxiv.org/abs/1401.7559 Exoplanets versus brown dwarfs: the CoRoT view and the future https://arxiv.org/abs/1604.00917 Defining and cataloging exoplanets: The exoplanet.eu database https://arxiv.org/abs/1106.0586 A Definition for Giant Planets Based on the Mass-Density Relationship https://arxiv.org/abs/1506.05097 Spatial differences between stars and brown dwarfs: a dynamical origin? https://arxiv.org/abs/1403.7053v1 Hints for Small Disks around Very Low-Mass Stars and Brown Dwarfs https://arxi

Watch Paradigms Here: http://vrv.co/paradigms And please let me know what you think! Paradigms is a pilot for a new show about how we know what we know, produced in collaboration with MinuteEarth (http://youtube.com/minuteearth), Veritasium (http://youtube.com/veritasium), and Aatish Bhatia. The first episode is about the science of seeing, from the extramission theories of the ancient Greeks (like Plato and Euclid and Galen) to the Islamic scientist Ibn al-Haytham (Alhazen) who studied the optics of pinhole chambers and images, to Johannes Kepler who understood the role lenses play in vision, to the modern era where we now know that the brain plays a huge role in seeing & processing images from the eyes, too! Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6

Go to http://brilliant.org/MinutePhysicsSpecialRelativity to learn more about spacetime diagrams and for 20% off a premium subscription to Brilliant. This video is chapter 2 in my series on special relativity, and it covers spacetime diagrams, rotational and translational symmetry of both time and space, how certain transformations preserve distances (measured in terms of a reference like a meter or second), and so on. We'll wait until the next video to talk about Lorentz transformations, relativity of velocity, minkowski diagrams, and the speed of light. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics And facebook - http://facebook.com/minutephysics And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6 Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich

Thanks to http://www.brilliant.org/minutephysics for supporting this video! Thanks to my friend Mark Rober (https://www.youtube.com/channel/UCY1kMZp36IQSyNx_9h4mpCg) for making the spacetime globe, and to Grant Sanderson (https://www.youtube.com/3blue1brown) for inspiration. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This is the first in a series of videos about special relativity. This is definitely not an academic course, but it's going to be a more in depth and developed exploration of a single topic than a typical standalone MinutePhysics video. I've been greatly inspired (and heckled) to do this by my friend Grant Sanderson of 3blue1brown who's set the standard for this kind of thing with his excellent series - serieses? - on calculus and linear algebra. So, special relativity. Special relativity is one of the most popularly famous ideas in physics – it's that thing that Einstein figured out about the spe

Thanks to the James Webb Space Telescope (JWST) and Space Telescope Science Institute for supporting this video. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about the astronomical amount of astronomical evidence for black holes, ranging from x-ray binaries with accretion disks, supermassive infrared-radiating galactic nuclei black holes, orbital characteristics of high mass binaries, and direct gravitational wave detection of inspiraling merging black hole binaries with LIGO. Yes, they're real. REFERENCES Interactive: Masses in the Stellar Graveyard https://ligo.northwestern.edu/media/mass-plot/index.html Galactic Center Orbital Models and Inner Stellar Distributions Data provided by Andrea Ghez and Sylvana Yelda, UCLA (obtained with the Keck Telescopes) Visualization by Stuart Levy and Robert Patterson, National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign

Thanks to https://brilliant.org/minutephysics for sponsoring this video! Check out their black hole course at http://brilliant.org/minutephysicsblackhole Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about how efficient various reactions are at converting mass to energy (as we know from the Einstein mass-energy equivalence of E=mc^2). Antimatter is very efficient but it is not naturally-occurring. Chemical reactions like fire or explosions are very inefficient. Nuclear fission and nuclear fusion are better, but not amazing on an absolute scale. Non-rotating black holes (Schwarzschild) and rotating (Kerr) are by far the most efficient, due to their accretion disks and very small radius of their innermost stable circular orbits. REFERENCES: Periodic Videos Hydrogen Explosion in slow motion: https://www.youtube.com/watch?v=qOTgeeTB_kA CIA World Factbook Norway Energy Consumption: https://web.archive

Thanks to https://brilliant.org/minutephysics/ for sponsoring this video! Check out their black hole course at https://brilliant.org/minutephysicsblackhole Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ This video is about the Schwarzschild radius of a black hole, (its "event horizon"), and how much mass and density is required to reach the point of no return where an object like a star, neutron star, red giant, etc will collapse into a black hole singularity. You can calculate it yourself using just the volume equation for a sphere, and the equation for the Schwarzschild radius (and knowing the speed of light and Newton's gravitational constant). REFERENCES Lecture notes on black holes: http://eagle.phys.utk.edu/guidry/astro616/lectures/lecture_ch18.pdf Mass of cat: https://www.google.com/search?q=mass+of+cat&oq=mass+of+cat Schwarzschild radius: https://en.wikipedia.org/wiki/Schwarzschild_radius LIGO Neutron S

Simpson's Paradox Part 2. Thanks to Skillshare for supporting this video! Head to http://skl.sh/minutephysics for your first two months free. Comments disabled because the discourse failed to remain civil. This video is about how to tell whether or not university admissions are biased using statistics: aka, it's about Simpson's Paradox again! REFERENCES: Original Berkeley Grad Admissions Paper: https://www.unc.edu/~nielsen/soci708/cdocs/Berkeley_admissions_bias.pdf Interactive Simpson’s Paradox Explainer: http://vudlab.com/simpsons/ No Lawsuit, But Yes, Berkeley Study on Gender Bias https://www.refsmmat.com/posts/2016-05-08-simpsons-paradox-berkeley.html Statistics on college majors by gender: https://nces.ed.gov/programs/digest/2016menu\_tables.asp http://www.npr.org/sections/money/2014/10/28/359419934/who-studies-what-men-women-and-college-majors http://www.randalolson.com/2014/06/14/percentage-of-bachelors-degrees-conferred-to-women-by-major-1970-2012/ Earnings by college major: http://time.com/mon