minutephysicsThis Product is supported by the NASA Heliophysics Education Activation Team (NASA HEAT), part of NASA’s Science Activation portfolio. The material contained in this document is based upon work supported by a National Aeronautics And Space Administration (NASA) grant or cooperative agreement. Any questions, findings, conclusions or recommendations expressed in this materials are those of the author and do not necessarily reflect the views of NASA.
We are in the Golden Age of Solar Eclipses, but only for the moment. In fact, I'd argue we're already past peak solar eclipse and it's all downhill from here.
The LAST Eclipse in Historyminutephysics2023-12-13 | This Product is supported by the NASA Heliophysics Education Activation Team (NASA HEAT), part of NASA’s Science Activation portfolio. The material contained in this document is based upon work supported by a National Aeronautics And Space Administration (NASA) grant or cooperative agreement. Any questions, findings, conclusions or recommendations expressed in this materials are those of the author and do not necessarily reflect the views of NASA.
We are in the Golden Age of Solar Eclipses, but only for the moment. In fact, I'd argue we're already past peak solar eclipse and it's all downhill from here.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Moons Orbit is WEIRDminutephysics2024-10-02 | Go to brilliant.org/MinutePhysics to try Brilliant for 30 days for FREE, and to get 20% off an annual premium subscription to Brilliant.
We think of the moon as orbiting the earth, following a spiraling trajectory as the earth itself orbits the sun. But this is wrong. Not only is the moon's orbit NOT a spiral... there's an argument that the moon actually orbits the sun, not the earth! The moon's trajectory is more like a 12-sided polygon with curved corners than it is a spiral or even a wiggly line.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichDoes Pressure Keep the Deep Ocean From Freezing?minutephysics2024-08-26 | Go to brilliant.org/minutephysics to try everything Brilliant has to offer for free for a full 30 days, and also get 20% off your annual premium subscription!
Pressure *can* melt ice - like, you only need 500 times atmospheric pressure to melt ice down to negative four degrees celsius. If you have 1000 times atmospheric pressure (like at the bottom of the Mariana trench), then you'll melt ice down to around negative nine celsius. But that's for fresh water. For salty sea water, things are different.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Color Temperature Paradoxminutephysics2024-07-24 | Go to brilliant.org/minutephysics to try everything Brilliant has to offer for free for a full 30 days, and also get 20% off your annual premium subscription!
If you take a piece of white paper into different lighting conditions, it will be an objectively different color in each situation, but our brains are clever enough to make us feel like it's still white - it's still the same piece of paper, after all. To match our experience, cameras have to do this, too, "balancing" the colors of an image so that a white object looks white under a given light, rather than some other color. And the typical unit to measure the color of a light is the Kelvin. Which is weird, because Kelvin is a unit for measuring temperature, not color. What temperature and the color in a photograph have to do with each other comes down to history and physics.
Solar eclipses don't just happen here on earth - moons of other planets also pass between those planets and the sun, resulting in various types of solar eclipses on Mars, Jupiter, Saturn, Uranus, Neptune, and even non-planets like Pluto, Eris and various asteroids. So, where are the best eclipses in the solar system? For that, we need a tier list.
This Product is supported by the NASA Heliophysics Education Activation Team (NASA HEAT), part of NASA’s Science Activation portfolio.
The material contained in this document is based upon work supported by a National Aeronautics And Space Administration (NASA) grant or cooperative agreement. Any questions, findings, conclusions or recommendations expressed in this materials are those of the author and do not necessarily reflect the views of NASA.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichWhy Do Eclipses Travel WEST to EAST?minutephysics2024-04-01 | The sun rises in the east, the moon rises in the east, and the stars rise in the east... but solar eclipses, oddly, come from the west. If total eclipses are caused by the sun and the moon, why don't they behave like the sun and the moon?
This Product is supported by the NASA Heliophysics Education Activation Team (NASA HEAT), part of NASA’s Science Activation portfolio.
The material contained in this document is based upon work supported by a National Aeronautics And Space Administration (NASA) grant or cooperative agreement. Any questions, findings, conclusions or recommendations expressed in this materials are those of the author and do not necessarily reflect the views of NASA.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichWhy Arent There Eclipses Every Month?minutephysics2024-03-21 | The moon orbits the earth once per month, which means the moon is on the sun side of the earth every month. So... "why aren't there eclipses every month?" is a question we will answer in this video!
This Product is supported by the NASA Heliophysics Education Activation Team (NASA HEAT), part of NASA’s Science Activation portfolio.
The material contained in this document is based upon work supported by a National Aeronautics And Space Administration (NASA) grant or cooperative agreement. Any questions, findings, conclusions or recommendations expressed in this materials are those of the author and do not necessarily reflect the views of NASA.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichShould You Wipe Off Your Sweat?minutephysics2023-12-20 | Want to donate to the highest-impact charities AND get your donation matched up to $100? Visit https://Givewell.org/MinutePhysics
If you’re in scorching heat, or when your body is working hard and you’ve got hot, hot sweat all over, sticky and stifling - does wiping off the sweat help you cool off? Or is it better to leave it on?
So in these conditions, a sweat-covered human can expect to evaporate ~.5-.75 L of water in an hour (For higher humidity (60-70%) it goes to ~.37-.5 L of water/hr). That amounts to ~0.25-0.35mm of sweat (covering the whole body) evaporated in an hour, or 6 micrometers every minute.
BUT that assumes all of the energy came from the person. If some proportion of it came from the air (~1/3-1/2?) then the person is only cooled down partially.
Mass of a human ~ 60-80kg (en.wikipedia.org/wiki/Body_weight), assuming ~specific heat of water, ie 4 kJ/kg/K, could decrease temp by ~4.5-5°C.
Energy used in moderate-hard exercise is ~20-30 kJ/kg/30 min, or ~40-60kJ/kg/h (http://www.weightloss.com.au/weight-loss/weight-loss-tools/exercise-energy-charts.html). Let’s say 50kJ/kg/h, which for average human amounts to 3000-4000 kJ/hr
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Created by Henry ReichBut What IS A Lens Flare?minutephysics2023-12-06 | Sign up for Brilliant (for free) and get 30 days of full access to all of their courses, go to brilliant.org/MinutePhysics - The first 200 people get 20% off a premium subscription!
A lot of people took pictures of the recent solar eclipse in North America and got photos where there’s a ghostly image of the eclipse floating in the sky nowhere near where the sun is!
REFERENCES: Lens flare prediction based on measurements with real-time visualization doi.org/10.1007/s00371-018-1552-4 Physically-Based Real-Time Lens Flare Rendering http://doi.acm.org/10.1145/1964921.1965003 From the Series of Articles on Lens Names: Tessar, by H. H. Nasse. Carl Zeiss Camera Lens Division March 2011
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Created by Henry ReichWhat if you pointed the Hubble telescope at Earth? @xkcd_whatifminutephysics2023-11-29 | The first video we created together with our friends at xkcd is out now! You can find it here: http://youtube.com/@xkcd_whatifThe Bizarre Physics of Electric Guitarsminutephysics2023-06-14 | To try everything Brilliant has to offer—free—for a full 30 days, visit http://brilliant.org/MinutePhysics The first 200 people get 20% off a premium subscription!
I was sent a magnetic guitar pick to review, so I reviewed it. Does it work? How? Why? What's the physics of electric guitar strings and pickups? Are magnets useful? Do they affect the strings? The pickups?
Thanks to Pete B. for loaning me the guitar.
Here are links to the youtube channel for the people who make the magnetic pick: youtube.com/@xpick
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Created by Henry ReichGeosynchronous Orbits are WEIRDminutephysics2022-12-22 | Go to givewell.org/minutephysics to have your first donation matched up to $100!
This video is about the physics of geosynchronous and geostationary orbits, why they exist, when they don't, when they're useful for communication/satellite TV, etc.
Kepler's 3rd law (which can be derived from Newton's law of gravitation and the centripetal force necessary for orbit as mr\omega^2=G\frac{mM}{r^2}, and using \omega=\frac{2\pi}{T}) is T = 2pi Sqrt(r^3/(GM)) where M is the mass of the central object, G is the gravitational constant. Alternatively, we can solve for r, r = (T^2/(4pi^2) GM)^(1/3) ~ T^(2/3)/M^(1/3) = (T^2/M)^(1/3).
There is a limit (kind of like the Roche limit but for rotations). A rotating solid steel ball or other chunk of metal that has tensile strength (ie that isn't just a pile of stuff held together by gravity like most planets) would be able to spin faster.
Calculate how much of a planet's surface you can see from a given geosynchronous orbit/radius? (Obviously for lower ones you can see less, etc) - d/(2(R+d)) where d is distance to surface, ie, R is sphere radius, R+d is object radius from sphere center.
Let's plug that in with r being the geostationary orbit radius. That is, we have \frac{1}{2} \left(1- \left(\frac{4 \pi^2 R^3}{T^2 G M }\right)^{1/3}\right)
Average density of a sphere \rho is given by \rho =M/(\frac{4}{3}\pi R^3), ie \rho=\frac{3M}{4 \pi R^3} aka
\frac{M}{R^3}=\frac{4}{3}\pi \rho.
So we can convert the "fraction of planet surface seen" to
So as either \rho or T\to \infty, the fraction goes to a maximum of \frac{1}{2}. And the point of "singularity" where the orbit coincides with the surface is where G\rho T^2=3\pi, aka \rho=\frac{3\pi}{GT^2}. For a rotation period of 3600s, that corresponds to a density \rho \approx 11000kg/m^3, which is roughly twice the density of the earth. For a rotation period of 5400s, we have \rho\approx 4800kg/m^3, which is basically the density of the earth.
Alternately, if we plug the density of the earth in to an orbit of period 5400s, we get as a fraction of the planet seen:
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Created by Henry ReichWhy Penrose Tiles Never Repeatminutephysics2022-12-01 | The first 200 people to brilliant.org/minutephysics get 20% off an annual premium subscription to Brilliant. Thanks to Brilliant for their support.
This video is about a better way to understand Penrose tilings (the famous tilings invented by Roger Penrose that never repeat themselves but still have some kind of order/pattern).
This project was a collaboration with Aatish Bhatia (https://aatishb.com).
Music algorithmically generated, algorithm designed by Henry Reich
N.G. de Bruijn’s paper introducing the pentagrid/Penrose idea: https://www.math.brown.edu/reschwar/M272/pentagrid.pdf
De Bruijn, N.G., 1981. Algebraic theory of Penrose’s non-periodic tilings of the plane. Kon. Nederl. Akad. Wetensch. Proc. Ser. A, 43(84), pp.1-7.
Here are some excellent in-depth references on how to construct Penrose Tiles Using the Pentagrid Method: Penrose Tilings Tied up in Ribbons by David Austin: http://www.ams.org/publicoutreach/feature-column/fcarc-ribbons The Empire Problem in Penrose Tilings by Laura Effinger-Dean: http://www.cs.williams.edu/~bailey/06le.pdf Pentagrids and Penrose Tilings by Stacy Mowry & Shriya Shukla: https://web.williams.edu/Mathematics/sjmiller/public_html/hudson/HRUMC-Mowry&Shukla_Pentagrids%20and%20Penrose.pdf Penrose Tiling by Andrejs Treibergs: http://www.math.utah.edu/~treiberg/PenroseSlides.pdf Algebraic Theory of Penrose's Non-Periodic Tilings of the Plane by N. G. de Bruijn: https://www.math.brown.edu/reschwar/M272/pentagrid.pdf Particularly good and helpful, and (we think) an undergrad thesis which is impressive!: http://www.cs.williams.edu/~bailey/06le.pdf
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichFreezing water expands. What if you dont let it?minutephysics2022-10-14 | The first 200 people to brilliant.org/minutephysics get 20% off an annual premium subscription to Brilliant. Thanks to Brilliant for their support.
FOR INTERNATIONAL EDITIONS, Including the UK and Germany, click here: xkcd.com/what-if-2
The #1 New York Times bestselling author of What If? and How To answers more of the weirdest questions you never thought to ask
The millions of people around the world who read and loved What If? still have questions, and those questions are getting stranger. Thank goodness xkcd creator Randall Munroe is here to help. Planning to ride a fire pole from the Moon back to Earth? The hardest part is sticking the landing. Hoping to cool the atmosphere by opening everyone’s freezer door at the same time? Maybe it’s time for a brief introduction to thermodynamics. Want to know what would happen if you rode a helicopter blade, built a billion-story building, made a lava lamp out of lava, or jumped on a geyser as it erupted? Okay, if you insist.
Before you go on a cosmic road trip, feed the residents of New York City to a T. rex, or fill every church with bananas, be sure to consult this practical guide for impractical ideas. Unfazed by absurdity, Munroe consults the latest research on everything from swing-set physics to airliner catapult–design to answer his readers’ questions, clearly and concisely, with illuminating and occasionally terrifying illustrations. As he consistently demonstrates, you can learn a lot from examining how the world might work in very specific extreme circumstances.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichPassing A Portal Through Itselfminutephysics2022-09-01 | Nebula Classes - Great classes by your favorite creators on a creator-owned streaming service: 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 :)
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichHow Many Fossils to Go an Inch? (ft. Robert Krulwich)minutephysics2022-08-18 | A beautiful guest video by Robert Krulwich and Nate Milton
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichAnother Portal Paradoxminutephysics2022-08-04 | We have a course on Brilliant! And the first 200 people to 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!
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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichMost Collisions Are Secretly in One Dimensionminutephysics2022-05-26 | The first 200 people to brilliant.org/MinutePhysics get 20% off 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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichIs Anything on the Internet Real?minutephysics2021-12-22 | GiveWell is matching donations from first-time donors dollar for dollar up to $250. Click on bit.ly/3DvVik8 to donate and be sure to use the fundraiser code MINUTEPHYSICS at checkout to make sure your donation gets matched.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Problem With The Butterfly Effectminutephysics2021-10-21 | The first 200 people to go to brilliant.org/minutephysics get 20% off a Premium subscription to Brilliant
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Rocket & String Paradoxminutephysics2021-08-18 | 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?
John Baez on Bell's Spaceship Paradox, Rindler Acceleration, etc https://math.ucr.edu/home/baez/physics/Relativity/SR/BellSpaceships/spaceship_puzzle.html
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichA Better Way To Picture Atomsminutephysics2021-05-19 | 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
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
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Created by Henry ReichWindmills Are NOT Like Damsminutephysics2021-04-01 | Watch the bonus material cut from this video at nebula.tv/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??
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichWhy Do Boats Make This Shape?minutephysics2021-03-21 | Go to nebula.tv/minutephysics to get access to Nebula (where you can watch the extended version of this video), plus you'll get a 20% 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...
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Physics of Windmill Designminutephysics2021-03-02 | This video was created in partnership with Bill Gates, inspired by his new book “How to Avoid a Climate Disaster.” Find out more here: 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
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Created by Henry ReichGeneral Relativity Explained in 7 Levels of Difficultyminutephysics2021-02-18 | Go to nebula.tv/minutephysics to get access to Nebula (where you can watch the extended version of this video), plus you'll get a 20% 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
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Created by Henry ReichWhy LESS Sensitive Tests Might Be Betterminutephysics2021-01-14 | Thanks to Brilliant for sponsoring this video - the first 200 people to click on brilliant.org/MinutePhysics will get 20% off a Premium subscription to Brilliant.
This video written & produced in collaboration with Aatish Bhatia, 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 larremorelab.github.io
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) medrxiv.org/content/10.1101/2020.12.02.20240648v1
Open letter signed by epidemiologists and infectious disease experts supporting widespread & frequent rapid antigen testing for COVID-19: rapidtests.org/expert-letter
More information on various COVID-19 tests: https://chs.asu.edu/diagnostics-commons/testing-commons
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.
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Created by Henry ReichThe Astounding Physics of N95 Masksminutephysics2020-06-18 | Head to 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 - aatishb.com To learn more about using & decontaminating N95 masks: n95decon.org
Thanks to Manu Prakash for useful discussion and feedback (Manu is involved with the N95 decontamination project)
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).
“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. arxiv.org/pdf/2004.13494.pdf
Scientific consortium for data-driven study of N95: 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. 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. ncbi.nlm.nih.gov/pmc/articles/PMC7202248
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Created by Henry ReichHow To Tell If Were Beating COVID-19minutephysics2020-03-27 | 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!
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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichHow to Tell Matter From Antimatter | CP Violation & The Ozma Problemminutephysics2020-02-26 | This video was made with the support of the Heising Simons Foundation.
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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichReimagining the Periodic Tableminutephysics2019-12-20 | 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!!
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichWhy Do Mirrors Flip Left & Right (but not up & down)?minutephysics2019-12-06 | Go to nebula.tv/minutephysics to get access to Nebula (where you can watch MinuteBody) plus you'll get a 20% discount on an annual subscription.
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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichDo Photons Cast Shadows?minutephysics2019-11-06 | Thanks to Nebula for their support. Go to nebula.tv/minutephysics to get Nebula!
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.
Ask an Astrophysicist on gamma ray scattering and energies in cosmology http://teacherlink.ed.usu.edu/tlnasa/reference/imaginedvd/files/imagine/docs/askastro/answers/970412e.html
Detecting vacuum birefringence with X-ray free electron lasers and high-power optical lasers https://indico.desy.de/indico/event/12654/session/2/contribution/8/material/slides/0.pdf
Vacuum birefringence in the head-on collision of XFEL and optical high-intensity laser pulses arxiv.org/pdf/1807.03302.pdf
ATLAS makes first direct detection of Light-by-light scattering at the LHC https://atlas.cern/updates/press-statement/atlas-sees-first-direct-evidence-light-light-scattering-high-energy
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Man Who Corrected Einsteinminutephysics2019-10-15 | 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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichProtecting Privacy with MATH (Collab with the Census)minutephysics2019-09-12 | 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 census.gov/about/policies/privacy/statistical_safeguards.html or search "differential privacy" at http://census.gov.
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: 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 privacy: A Bayesian formulation. 2015. https://arxiv.org/abs/0803.3946
Daniel Kifer and Ashwin Machanavajjhala. A rigorous and customizable framework for privacy. In ACM Symposium on Principles of Database Systems (PODS), 2012.
Daniel Kifer and Ashwin Machanavajjhala. Pufferfish: A framework for mathematical privacy definitions. ACM Trans. Database Syst., 39(1):3, 2014.
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 measuring the radioactivity of your teeth. He offers tips for taking a selfie with a telescope, crossing a river by boiling it, and powering your house by destroying the fabric of space-time. And if you want to get rid of the book once you're done with it, he walks you through your options for proper disposal, including dissolving it in the ocean, converting it to a vapor, using tectonic plates to subduct it into the Earth's mantle, or launching it into the Sun.
By exploring the most complicated ways to do simple tasks, Munroe doesn't just make things difficult for himself and his readers. As he did so brilliantly in What If?, Munroe invites us to explore the most absurd reaches of the possible. Full of clever infographics and amusing illustrations, How To is a delightfully mind-bending way to better understand the science and technology underlying the things we do every day.
REFERENCES
How To (Randall Munroe) - see above for links!
Rock melting points http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/meltrock.html
Syracuse University Researchers Make Lava Using Keweenawan Basalt http://lavaproject.syr.edu/making-lava/making.html
BEDROCK GEOLOGY OF WISCONSIN MAP: UNIVERSITY OF WISCONSIN–EXTENSION Geological and Natural History Survey
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichWhy Some Days Aren’t 24 Hoursminutephysics2019-08-23 | Check out the "What is a Day?" interactive video at labs.minutelabs.io/what-is-a-day It's super cool!! (and made by Jasper Palfree & the MinuteEarth/MinutePhysics team)
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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichEinsteins Biggest Blunder, Explainedminutephysics2019-08-01 | Thanks to Brilliant for supporting MinutePhysics. Get 20% off a premium subscription at 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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichThe Portal Paradoxminutephysics2019-06-28 | Go to nebula.tv/minutephysics to get access to Nebula, plus you'll get a 20% discount on an annual subscription.
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.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichOur Ignorance About Gravityminutephysics2019-06-20 | Thanks to the Heising Simons Foundation (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.
Torsion balance experiments: A low-energy frontier of particle physics E.G. Adelberger, J.H. Gundlach, B.R. Heckel, S. Hoedl, S. Schlamminger doi:10.1016/j.ppnp.2008.08.002
TESTS OF THE GRAVITATIONAL INVERSE-SQUARE LAW E.G. Adelberger, B.R. Heckel, and A.E. Nelson Annu. Rev. Nucl. Part. Sci. 2003. 53:77–121 doi: 10.1146/annurev.nucl.53.041002.110503
Physical Review A, Vol 33, No 1: Improved result for the accuracy of Coulomb's law: A review of the Williams, Faller, and Hill experiment. Lewis P. Fulcher.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry ReichI Had to Build a Custom Mute Switch for my Violinminutephysics2019-06-04 | Thanks to Brilliant for supporting this video! The first 200 people to go to brilliant.org/MinutePhysics will get 20% off a premium subscription to Brilliant.
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.
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).
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry ReichHow Quantum Computers Break Encryption | Shors Algorithm Explainedminutephysics2019-05-01 | Go to http://www.dashlane.com/minutephysics to download Dashlane for free, and use offer code minutephysics for 10% off Dashlane Premium!
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).
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 as Freon 152a, Ethylidene difluoride, Ethylidene fluoride, HFC-152a, R-152a, and DFE.