The Ice/Water Paradox

The first 200 people to https://brilliant.org/minutephysics get 20% off an annual premium subscription to Brilliant. Thanks to Brilliant for their support. 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


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Passing A Portal Through Itself

Nebula Classes - Great classes by your favorite creators on a creator-owned streaming service: https://nebulaclasses.com/minutephysics This video is about what happens if you try to pass a portal (like in the video game Portal or Portal 2) through itself - do you get a paradox? Infinite recursion? Impossibility? Contradiction? The end of the world? Collapse of the wavefunction? Ultimately it ends up looking beautiful and weird and recursive and... just watch the video :) 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


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Burning the Dead for Power (ft. Robert Krulwich)

A beautiful guest video by Robert Krulwich and Nate Milton 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


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Another Portal Paradox

We have a course on Brilliant! And the first 200 people to https://brilliant.org/minutephysics get 20% off an annual premium subscription to Brilliant, with full access to all courses, including ours. What happens if you extend a piston through a portal? Or try to sandwich a cube between two portals? That's right, it's time to explore more portal paradoxes! 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


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The Trinity of Quality

The first 200 people to https://brilliant.org/MinutePhysics/ get 20% off an annual Premium subscription to Brilliant. MinutePhysics is on Patreon: https://patreon.com/minutephysics In order to make something good, you need to have the right combination of three things: Quality, Discernment and Taste. This video is about quality vs quantity, the paradox of quality, how to make good content and good videos, etc. Based on my experience over the last decade running a collaborative creative business, MinuteEarth, where we do regular internal reflection and training on the craft of science communication. 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


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Most Collisions Are Secretly In One Dimension

The first 200 people to https://brilliant.org/MinutePhysics/ get 20% of an annual Premium subscription to Brilliant. This video is about elastic and inelastic collisions in 1D, 2D and 3D - and how the collision of conservation of energy with conservation of momentum, plus a secret direction, results in a completely predetermined behavior for most collisions. REFERENCES 1D Collision Calculator: http://hyperphysics.phy-astr.gsu.edu/hbase/col1d.html#c1 Elastic collision of spheres Wolfram https://demonstrations.wolfram.com/ElasticCollisionsOfTwoSpheres/ Oblique collisions of two 2D spheres https://iopscience.iop.org/article/10.1088/1361-6404/aab330 Ballistic Pendulum http://hyperphysics.phy-astr.gsu.edu/hbase/balpen.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 entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich


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The Problem With The Butterfly Effect

The first 200 people to go to https://brilliant.org/minutephysics get 20% off a Premium subscription to Brilliant 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


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How Did Whales Get So Big?

Get the new MinuteEarth book at: https://www.minuteearth.com/books !! Support MinutePhysics on Patreon: http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich


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Can Length Contraction Tear You Apart?

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 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 entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich


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A Better Way To Picture Atoms

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


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How Much Wind Should a Windmill Mill?

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


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Why Do Boats Make This Pattern?

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://journals.aps.org/prl/abstract/10.1103/PhysRevLett.110.214503 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


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The Physics of Windmill Design

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-turbines-usually-have-3-blades-f7f95d714869 Wind Power Fundamentals http://web.mit.edu/windenergy/windweek/Presentations/Wind%20Energy%20101.pdf Wind Power Explained https://www.calcunation.com/blogs.php/the-physics-behind-wind-turbines/ Drag Coefficient http://dx.doi.org/10.1615/AtoZ.d.drag_coefficient Reynolds Number and Drag http://www2.eng.cam.ac.uk/~mpj1001/learnfluidmechanics.org/LFM_blank_notes/handout_8_v3.pdf Reynolds Number https://en.wikipedia.org/wiki/Reynolds_number Viscosity of Air https://en.wikipedia.org/wiki/Viscosity#Air 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


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General Relativity Explained in 7 Levels of Difficulty

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 relativity - on a small scale, quantum mechanics. And where they meet... there's still work to be done. REFERENCES Wald's textbook - General Relativity Hartle's textbook - Gravity: An Introduction to Einstein's General Relativity Carlo Rovelli History of Quantum Gravity: https://cds.cern.ch/record/442809/files/0006061.pdf Leon Rosenfeld 1930 paper on quantum gravity: http://www.edoc.mpg.de/438547 Kerr Metric Solution - https://en.wikipedia.org/wiki/Eddington%E2%80%93Finkelstein_coordinates Schwarzschild Metric - https://en.wikipedia.org/wiki/Schwarzschild_metric Eddington-Finkelstein Coordinates - https://en.wikipedia.org/wiki/Eddington%E2%80%93Finkelstein_coordinates 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


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The Case for LESS Sensitive COVID Tests

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. https://advances.sciencemag.org/content/7/1/eabd5393.abstract The effectiveness of population-wide, rapid antigen test based screening in reducing SARS-CoV-2 infection prevalence in Slovakia. (pre-print, not yet peer reviewed) https://www.medrxiv.org/content/10.1101/2020.12.02.20240648v1 Effective Testing and Screening for Covid-19. https://www.rockefellerfoundation.org/wp-content/uploads/2020/09/A-National-Decision-Point-Effective-Testing-Screening-for-Covid-19-Full-Report.pdf Brown University & Harvard University modeling of COVID-19 testing shortfall. https://globalepidemics.org/testing-targets/ Fast Coronavirus Tests are coming. https://media.nature.com/original/magazine-assets/d41586-020-02661-2/d41586-020-02661-2.pdf Open letter signed by epidemiologists and infectious disease experts supporting widespread & frequent rapid antigen testing for COVID-19: https://www.rapidtests.org/expert-letter More information on various COVID-19 tests: https://chs.asu.edu/diagnostics-commons/testing-commons Field performance and public health response using the BinaxNOW Rapid SARS-CoV-2 antigen detection assay during community-based testing. https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa1890/6052342 Performance of an Antigen-Based Test for Asymptomatic and Symptomatic SARS-CoV-2 Testing at Two University Campuses. https://www.cdc.gov/mmwr/volumes/69/wr/mm695152a3.htm Asymptomatic Spread: People without symptoms spread virus in more than half of cases, CDC model finds https://www.washingtonpost.com/science/2021/01/07/covid-asymptomatic-spread/ (More than half of all) SARS-CoV-2 Transmission From People Without COVID-19 Symptoms. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774707 Three Quarters of People with SARS-CoV-2 Infection are Asymptomatic: Analysis of English Household Survey Data. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549754/ Viral Load Curve: SARS-CoV-2 viral dynamics in acute infections. (pre-print, not yet peer reviewed) https://www.medrxiv.org/content/10.1101/2020.10.21.20217042v2 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


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minutephysics: Join Me in Voting! (If you can vote in the US)

Teacher or professor: minutephysics
Subject: Physics
Content of the Lesson: Go to http://www.vote.org or https://www.ballotready.org for information about voting in your area. To all my non-US-voting viewers... thanks for your support, and I bet you know someone in the US who can vote :) Created by Henry Reich


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minutephysics: Why Masks Work BETTER Than You'd Think

Teacher or professor: minutephysics
Subject: Physics
Content of the Lesson: 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 Mask FAQ Test Results: https://www.maskfaq.com/test-results The Effect of Mask Use on the Spread of Influenza During a Pandemic: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1539-6924.2010.01428.x Calibrated Intervention and Containment of the COVID-19 Pandemic: https://arxiv.org/ftp/arxiv/papers/2003/2003.07353.pdf Cloth Mask Breathability and Filtration Efficiency Technical Report: https://static1.squarespace.com/static/5e8126f89327941b9453eeef/t/5f2c4463a5c9f75a38d2b26f/1596736614213/N95DECON_cloth_mask_breathability_filtrationtechnical_report_v1_200804.pdf What kind of mask should I be wearing to protect against COVID-19? http://built-envi.com/what-kind-of-mask-should-i-be-wearing-to-protect-against-covid-19/ Masks for all? The science says yes. https://www.fast.ai/2020/04/13/masks-summary/ The Real Reason to Wear a Mask: https://medium.com/the-atlantic/the-real-reason-to-wear-a-mask-e6405abbc484 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


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minutephysics: The Astounding Physics of N95 Masks

Teacher or professor: minutephysics
Subject: Physics
Content of the Lesson: Head to http://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_wWeGQ9U2iGy0y4QajBeOL8RqAZIQ/edit “Electrostatic charge contributes as much as 95% of the filtration efficiency” Molina, A., Vyas, P., Khlystov, N., Kumar, S., Kothari, A., Deriso, D., ... & Prakash, M. (2020). Project 1000 x 1000: Centrifugal melt spinning for distributed manufacturing of N95 filtering facepiece respirators. arXiv preprint arXiv:2004.13494. https://arxiv.org/pdf/2004.13494.pdf Tsai, P. P., Schreuder-Gibson, H., & Gibson, P. (2002). Different electrostatic methods for making electret filters. Journal of electrostatics, 54(3-4), 333-341. https://www.researchgate.net/profile/Phillip_Gibson/publication/222659741_Different_electrostatic_methods_for_making_electret_filters/links/5a5912cba6fdcc3bfb5ab21e/Different-electrostatic-methods-for-making-electret-filters.pdf History of Electrets Jefimenko, O. D., & Walker, D. K. (1980). Electrets. The Physics Teacher, 18(9), 651-659. https://aapt.scitation.org/doi/abs/10.1119/1.2340651 Physics of Air Filtration Hinds, W. C. (1999). Aerosol technology: properties, behavior, and measurement of airborne particles. John Wiley & Sons. https://www.wiley.com/en-us/Aerosol+Technology%3A+Properties%2C+Behavior%2C+and+Measurement+of+Airborne+Particles%2C+2nd+Edition-p-9780471194101 Scientific consortium for data-driven study of N95: https://www.n95decon.org/ N95 & virus particle sizes Bałazy, A., Toivola, M., Adhikari, A., Sivasubramani, S. K., Reponen, T., & Grinshpun, S. A. (2006). Do N95 respirators provide 95% protection level against airborne viruses, and how adequate are surgical masks?. American journal of infection control, 34(2), 51-57. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.488.4644&rep=rep1&type=pdf Harnish, D. A., Heimbuch, B. K., Husband, M., Lumley, A. E., Kinney, K., Shaffer, R. E., & Wander, J. D. (2013). Challenge of N95 filtering facepiece respirators with viable H1N1 influenza aerosols. Infection Control & Hospital Epidemiology, 34(5), 494-499. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646082/ Liao, L., Xiao, W., Zhao, M., Yu, X., Wang, H., Wang, Q., ... & Cui, Y. (2020). "Can N95 respirators be reused after disinfection? How many times?. ACS nano. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202248/ 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


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minutephysics: How Soon Will COVID-19 Peak? (And How To Tell)

Teacher or professor: minutephysics
Subject: Physics
Content of the Lesson: 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 see the interactive graph 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 on log scales and growth curves explained in the context of COVID-19 in different countries) This video is a collaboration with Aatish Bhatia about how to see the COVID-19 tipping point - we present a better way to graph COVID-19 coronavirus cases using a logarithmic scale in "phase space" - plotting the growth rate against the cumulative cases, rather than either of these against time. 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


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minutephysics: How to Detect Antimatter Aliens | CP Violation & The Ozma Problem

Teacher or professor: minutephysics
Subject: Physics
Content of the Lesson: 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-violation/ Electroweak CP Violation on Scholarpedia http://www.scholarpedia.org/article/CPviolationinelectroweakinteractions The Wu Experiment https://en.wikipedia.org/wiki/Wuexperiment Martin Gardner, The New Ambidextrous Universe https://books.google.com/books?id=kdLGa8cPPUC&lpg=PP1&pg=PR2#v=onepage&q&f=false Lecture notes on CP Violation and the CKM Matrix, Cambridge (Mark Thomson) https://www.hep.phy.cam.ac.uk/thomson/lectures/partIIIparticles/Handout122009.pdf Homochirality https://en.wikipedia.org/wiki/Homochirality L-glucose (vs D-glucose) https://en.wikipedia.org/wiki/L-Glucose Radioactive Nucleus Decay http://www.radioactivity.eu.com/site/pages/RadioactiveSeries.htm CP Violation in Semi-Leptonic Decays (SEE PAGE 426 for reference to definition of MATTER) https://www.hep.phy.cam.ac.uk/thomson/lectures/partIIIparticles/Handout122009.pdf Kaon Decay Modes http://pdg.lbl.gov/2012/listings/rpp2012-list-K-zero-L.pdf Flipped bowling Jesus scene in Big Lebowski https://www.youtube.com/watch?v=lWz8NGIisMo Isotopes of Uranium https://en.wikipedia.org/wiki/Isotopesofuranium Beta Decay https://en.wikipedia.org/wiki/Betadecay The Wu Experiment https://en.wikipedia.org/wiki/Wuexperiment Kaons https://en.wikipedia.org/wiki/Kaon CP Violation in Symmetry Magazine https://www.symmetrymagazine.org/article/charge-parity-violation Physics Stack Exchange on CP Violation https://physics.stackexchange.com/questions/160511/what-cp-violating-processes-do-we-know-of 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


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