minutephysics

Simply put: cool physics and other sweet science.
"If you can't explain it simply, you don't understand it well enough."
~Rutherford via Einstein? (wikiquote)
Created by Henry Reich

229 videos

2 weeks ago

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 Relativity (Einstein)
https://einsteinpapers.press.princeton.edu/vol6-trans/110
The Foundation of the General Theory of Relativity (Albert Einstein)
https://einsteinpapers.press.princeton.edu/vol6-trans/158
Cosmological Considerations in the General Theory of Relativity
https://einsteinpapers.press.princeton.edu/vol6-trans/433
Einstein Wrongly Criticizes Alexander Friedmann
https://einsteinpapers.press.princeton.edu/vol13-trans/301
Alexander Friedmann Corrects Einstein
https://einsteinpapers.press.princeton.edu/vol13-trans/363
Einstein Admits his Mathematical Mistake
https://einsteinpapers.press.princeton.edu/vol14-trans/77
The Field Equations of Gravitation
https://einsteinpapers.press.princeton.edu/vol6-trans/129
George Gamow
https://en.wikipedia.org/wiki/George_Gamow
Mach’s Principle
https://en.wikipedia.org/wiki/Mach%27s_principle
Equivalence Principle
https://en.wikipedia.org/wiki/Equivalence_principle
Sean Carroll and William Press Paper
https://preposterousuniverse.com/wp-content/uploads/cpt92.pdf
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

Добавлена

1 month ago

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.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

Добавлена

2 months ago

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 Experiment
http://dx.doi.org/10.1119/1.13149
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.
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

Добавлена

2 months ago

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://en.wikipedia.org/wiki/Pickup_%28music_technology%29
Microphone mute pedal on “I like to make stuff”
https://iliketomakestuff.com/make-microphone-mute-pedal/
Balanced vs unbalanced audio:
http://www.aviom.com/blog/balanced-vs-unbalanced/
Balanced signals on wikipedia:
https://en.wikipedia.org/wiki/Balanced_audio
Phantom Power:
http://acousticguitar.com/everything-you-need-to-know-about-microphone-phantom-power/
Phantom Power explained on Sweetwater:
https://www.sweetwater.com/insync/how-phantom-power-works/
Piezoelectricity:
https://en.wikipedia.org/wiki/Piezoelectricity#Mechanism
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

Добавлена

3 months ago

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/gtps7/s7pkey.html
Modulo Multiplication Group Tables http://mathworld.wolfram.com/ModuloMultiplicationGroup.html
Difference of squares factorization https://en.wikipedia.org/wiki/Difference_of_two_squares
Euclid’s Algorithm https://en.wikipedia.org/wiki/Euclideanalgorithm
Rational sieve for factoring https://en.wikipedia.org/wiki/Rational_sieve
General Number field Sieve https://en.wikipedia.org/wiki/Generalnumberfieldsieve
Scott Aaronson blog post about Shor’s Algorithm https://www.scottaaronson.com/blog/?p=208
Experimental implementation of Shor’s Algorithm (factoring 15, 21, and 35) https://arxiv.org/pdf/1903.00768.pdf
Adiabatic Quantum Computation factoring the number 291311 https://arxiv.org/pdf/1706.08061.pdf
Scott Aaronson course notes https://www.scottaaronson.com/qclec/ https://www.scottaaronson.com/qclec/combined.pdf
Shor’s Algorithm on Quantiki https://www.quantiki.org/wiki/shors-factoring-algorithm
TLS And SSL use RSA encryption https://en.wikipedia.org/wiki/TransportLayerSecurity
Dashlane security whitepaper https://www.dashlane.com/download/DashlaneSecurityWhitePaperOctober2018.pdf
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

Добавлена

3 months ago

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/minutephysics
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Добавлена

4 months ago

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 as Freon 152a, Ethylidene difluoride, Ethylidene fluoride, HFC-152a, R-152a, and DFE.
Thanks to Tino and Hannah!
REFERENCES
CRC Air Duster Safety Data Sheet
http://docs.crcindustries.com/msds/5185.pdf
Latent Heat of vaporization
https://en.wikipedia.org/wiki/Latentheat
1,1-difluoroethane chemical and physical properties
https://webbook.nist.gov/cgi/cbook.cgi?ID=C75376&Mask=3FFF
1,1-difluoroethane on wikipedia
https://en.wikipedia.org/wiki/1,1-Difluoroethane
Free Expansion of Real Gases, Goussard, 1993
http://dx.doi.org/10.1119/1.17417
Joule-Thompson Expansion Course Notes
http://tccc.iesl.forth.gr/education/local/Labs-PC-II/JT.pdf
Properties of 1,1-difluoroethane
http://www.inchem.org/documents/sids/sids/75376.pdf
https://pubchem.ncbi.nlm.nih.gov/compound/11-difluoroethane
Medical Effects of difluoroethane
https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+5205
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

Добавлена

5 months ago

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

Добавлена

6 months ago

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!
Created by Henry Reich

Добавлена

6 months ago

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

Добавлена

8 months ago

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 reality, and has been used as an experimental setup for weak measurements.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Добавлена

9 months ago

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 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

Добавлена

11 months ago

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 cones: https://www.focal.com/en/tmd-tuned-mass-damper
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

Добавлена

2 years ago

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

Добавлена

2 years ago

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

Добавлена

2 years ago

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 minute!
Created by Henry Reich

Добавлена

2 years ago

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 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

Добавлена

2 years ago

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¢er_lat=0¢er=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/222359947_fig2_Ping-pong-balls-are-good-macroscopic-examples-for-shells-as-they-display-the-main
Dented ping pong balls: http://www.katharine-yi.com/uploads/1/8/4/0/18406703/1399540277.png
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

Добавлена

2 years ago

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

Добавлена

2 years ago

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

Добавлена

2 years ago

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/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

Добавлена

2 years ago

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 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

Добавлена

2 years ago

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://arxiv.org/abs/1705.01952
VLA observations of the disk around the young brown dwarf 2MASS J044427+2512 https://arxiv.org/abs/1707.07197
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

Добавлена

2 years ago

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
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Добавлена

2 years ago

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

Добавлена

2 years ago

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 speed of light and space and time and E=mc^2! It changed our understanding of the universe. And its core ideas are accessible in principle to anyone who understands some basic algebra and geometry - you don't even need to know calculus!
And yet in spite of this, special relativity is one of the subjects in physics that confuses the most people, and in many cases turns them away from physics altogether.
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

Добавлена

2 years ago

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
http://avl.ncsa.illinois.edu/astrophysics/galactic-center-orbital-models-and-inner-stellar-distributions
Masses of observed black Holes:
https://stellarcollapse.org/bhmasses
Downloadable LIGO Data: https://losc.ligo.org/events/GW170817/
LIGO Neutron Star Binary Merger: http://www.astronomy.com/news/2017/10/ligo-detects-a-neutron-star-merger
Masses of observed neutron stars: https://stellarcollapse.org/nsmasses
Cygnus X-1 X-ray binary Black Hole: https://en.wikipedia.org/wiki/Cygnus_X-1#Star_system
Lecture notes on black holes: http://eagle.phys.utk.edu/guidry/astro616/lectures/lecture_ch18.pdf
Calvera isolated neutron star X-ray source: https://en.wikipedia.org/wiki/Calvera_(X-ray_source)
Scientific American: pulsar that behaves like a black hole
https://www.scientificamerican.com/article/black-hole-pretenders-may-be-superfast-spinning-pulsars/
Largest known neutron star: https://en.wikipedia.org/wiki/PSR_J0348%2B0432
http://simbad.u-strasbg.fr/simbad/sim-id?Ident=PSR+J0348%2B0432
Large Neutron Star: https://arxiv.org/abs/0712.0024
Wandering Black Hole: https://www.nasa.gov/mission_pages/chandra/x-ray-telescopes-find-evidence-for-wandering-black-hole.html
Sagittarius A* Black Hole Infrared emissions: https://arxiv.org/pdf/0911.4659.pdf
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

Добавлена

2 years ago

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.org/web/20120128032332/https://www.cia.gov/library/publications/the-world-factbook/rankorder/2042rank.html
Binding Energy: https://en.wikipedia.org/wiki/Binding_energy
Hydrogen molecular bonding: https://ocw.mit.edu/courses/chemistry/5-73-introductory-quantum-mechanics-i-fall-2005/lecture-notes/sec13.pdf
Gibbs free energy of water formation: https://en.wikipedia.org/wiki/Standard_Gibbs_free_energy_of_formation
Party Balloon Size Chart: https://broadwaypartyrental.com/wp-content/uploads/HELIUM-BALOON-CHART.pdf
Mass Excess https://en.wikipedia.org/wiki/Mass_excess
Table of Mass Excesses: http://www.nndc.bnl.gov/masses/mass.mas12
Deuterium-Tritium Hydrogen Fusion Energy Released: http://www.wolframalpha.com/input/?i=((deuterium+atomic+mass)%2B(tritium+atomic+mass)-(helium-4+atomic+mass)-(neutron+mass))%2F((deuterium+atomic+mass)%2B(tritium+atomic+mass))
Hydrogen to Helium Fusion chain efficiency: http://www.wolframalpha.com/input/?i=(4(proton+mass)-(helium+4+atomic+mass))%2F(4(proton+mass))
Uranium-235 fission efficiency: http://www.wolframalpha.com/input/?i=(neutron+mass%2B(uranium+235+atomic+mass)-(krypton+92+atomic+mass)-(barium+141+atomic+mass)-3(neutron+mass))%2F(neutron+mass%2B(uranium+235+atomic+mass))
Black Hole Accretion rates: http://www-astro.physics.ox.ac.uk/~garret/teaching/lecture7-2012.pdf
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

Добавлена

2 years ago

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 Star Binary Merger: http://www.astronomy.com/news/2017/10/ligo-detects-a-neutron-star-merger
Tolman-Oppenheimer-Volkoff Limit: https://en.wikipedia.org/wiki/Tolman%E2%80%93Oppenheimer%E2%80%93Volkoff_limit
Neutron Star Equation of State & Density: http://chimera.roma1.infn.it/OMAR/dottorato/papers/annurev-nucl-102711-095018.pdf
Neutron Star Radius: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.928.903&rep=rep1&type=pdf
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

Добавлена

2 years ago

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/money/collection-post/3829776/heres-what-the-average-grad-makes-right-out-of-college/
Wall Street Journal Article on Simpson’s Paradox: https://www.wsj.com/news/articles/SB125970744553071829
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

Добавлена

2 years ago

Thanks to YouTube RED’s new original series, LIFELINE, for sponsoring this video. Watch the first episode for free: https://www.youtube.com/watch?v=Ru4zkxNuJ_I
And thanks to my friends Sam and Niko (and all the rest) at the Corridor Digital channel for making awesome videos.
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
For ages I’ve been thinking about doing a video analyzing time travel in fiction and doing a comparison of different fictional time travels – some do use wormholes, some relativistic/faster than light travel with time dilation, some closed timelike curves, some have essentially “magic” or no consistent rules that make any sense, or TARDIS's, or whatever. This video is an explanation of how time travel functions in different popular movies, books, & shows – not how it works “under the hood", but how it causally affects the perspective of characters’ timelines (who has free will? can you change things by going back to the past or forwards into the future?). In particular, I explain Ender's Game, Planet of the Apes, Harry Potter and the Prisoner of Azkaban, Primer, Bill & Ted’s Excellent Adventure, Back to the Future, Groundhog Day, Looper, the video game “Braid”, and Lifeline.
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

Добавлена

2 years ago

Thanks to https://brilliant.org/minutephysics for sponsoring this video!
This video is about Simpson's paradox, a statistical paradox and ecological fallacy where seemingly contradictory results are implied by a single set of data depending on how it's grouped. The paradox can arise in medical studies, student test scores, and so on.
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
REFERENCES:
Interactive Simpson’s Paradox Explainer:
http://vudlab.com/simpsons/
Wisconsin vs Texas schools: http://educationnext.org/are-wisconsin-schools-better-than-those-in-texas/
Detailed analysis of Wisconsin vs Texas schools: http://iowahawk.typepad.com/iowahawk/2011/03/longhorns-17-badgers-1.html
National US Standardized Test Data: https://nces.ed.gov/nationsreportcard/naepdata/report.aspx?p=2-SCI-3-20153,20113,20093-SRPUV-SDRACE-NP,AL,AK,AZ,AR,CA,CO,CT,DE,DC,FL,GA,HI,ID,IL,IN,IA,KS,KY,LA,ME,MD,MA,MI,MN,MS,MO,MT,NE,NV,NH,NJ,NM,NY,NC,ND,OH,OK,OR,PA,RI,SC,SD,TN,TX,UT,VT,VA,WA,WV,WI,WY,DS-MN_MN-Y_J-0-0-5
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

Добавлена

2 years ago

The first 200 people to use http://skl.sh/minutephysics30 get 30% off a premium Skillshare subscription.
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
This video is about the international system of units (SI), the international prototype kilogram (the IPK or "le grande k"), and specifically, why we need to redefine our base units in terms of fundamental constants - aka, concepts & ideas - rather than physical objects. The second is already defined in terms of a certain number of oscillations of a photon of the ground state hyperfine splitting energy of Cesium, the meter is then defined as how far light travels in a particular fraction of a second, and hopefully soon, the kilogram will be defined either using the Avogadro approach of counting silicon atoms in a sphere, or using the Watt (Kibble) Balance approach of measuring Planck's constant, h, as used in the formula E=hf for the energy of a photon, which relates to mass via Einstein's famous E=mc^2.
REFERENCES:
Most Recent Kilogram/Planck Constant Measurement: https://www.nist.gov/news-events/news/2017/06/new-measurement-will-help-redefine-international-unit-mass
International Bureau of Weights and Measures page: http://www.bipm.org/en/measurement-units/base-units.html
Future Definitions of SI Base Units: http://www.bipm.org/en/measurement-units/rev-si/
Resolution to redefine Kilogram, ampere, kelvin and mole based on fundamental constants: http://www.bipm.org/en/CGPM/db/25/1/
Hyperfine levels of an atom (Cesium, in this case): https://en.wikipedia.org/wiki/Energy_level#Hyperfine_structure
https://en.wikipedia.org/wiki/Hyperfine_structure
Cesium: https://en.wikipedia.org/wiki/Caesium#Atomic_clocks
Atomic Clocks: https://en.wikipedia.org/wiki/Atomic_clock
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

Добавлена

2 years ago

Find more about investing in Rayton solar on http://startengine.com/startup/rayton-solar
And on http://www.RaytonSolar.com
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
This video is about using particle accelerators as part of the solar panel silicon wafer manufacturing process. The accelerators embed protons into the wafer crystals, allowing them to break and separate from the main crystal in much thinner wafers with no waste silicon. Thus, monocrystalline silicon can be used, which is more efficient.
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

Добавлена

2 years ago

Featuring 3Blue1Brown
Watch the 2nd video on 3Blue1Brown here: https://www.youtube.com/watch?v=MzRCDLre1b4
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
This video is about Bell's Theorem, one of the most fascinating results in 20th century physics. Even though Albert Einstein (together with collaborators in the EPR Paradox paper) wanted to show that quantum mechanics must be incomplete because it was nonlocal (he didn't like "spooky action at a distance"), John Bell managed to prove that any local real hidden variable theory would have to satisfy certain simple statistical properties that quantum mechanical experiments (and the theory that describes them) violate. Since then, GHZ and others have managed to extend the theoretical work, and Alain Aspect performed the first Bell test experiment in the late 1980s.
Thanks to Vince Rubinetti for the music: https://soundcloud.com/vincerubinetti/one-two-zeta
And thanks to Evan Miyazono, Aatish Bhatia, and Jasper Palfree for discussions and camaraderie during some of the inception of this video.
REFERENCES:
John Bell's Original Paper: http://inspirehep.net/record/31657/files/vol1p195-200_001.pdf
Quantum Theory and Reality: https://www.scientificamerican.com/media/pdf/197911_0158.pdf
"What Bell Did" By Tim Maudlin: https://arxiv.org/pdf/1408.1826
Bell's Theorem on Wikipedia: https://en.wikipedia.org/wiki/Bell%27s_theorem
2015 experimental confirmation that QM violates Bell's theorem: https://arxiv.org/pdf/1508.05949.pdf
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.250402
Bell's Theorem without Inequalities (GHZ): http://dx.doi.org/10.1119/1.16243
Kochen-Specker Theorem: https://en.wikipedia.org/wiki/Kochen–Specker_theorem
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

Добавлена

2 years ago

Join the AI conversation: http://AgeofAI.org
This video was based on Max’s book "Life 3.0”, which you can find at: http://amzn.to/2iEwe6w
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
We live in an era of self driving cars, autonomous drones, deep learning algorithms, computers that beat humans at chess and go, and so on. So it’s natural to ask, will artificial superintelligence replace humans, take our jobs, and destroy human civilization? Or will AI just become tools like regular computers. AI researcher Max Tegmark helps explain the myths and facts about superintelligence, the impending machine takeover, etc.
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

Добавлена

3 years ago

Footnote to the main video here: https://youtu.be/HUti6vGctQM
Feedback loops and spurious correlations!
REFERENCES:
Spurious correlations: http://www.tylervigen.com/spurious-correlations
Loopy by Nicky Case: http://ncase.me/loopy/
CERN/CMS paper on di-photon excess: https://cds.cern.ch/record/2139899
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

Добавлена

3 years ago

Have fun improving your math & physics skills! Head to https://brilliant.org/minutephysics/
Footnote video: https://www.youtube.com/watch?v=iMbcMMe0D_Y
This video is about how causal models (which use causal networks) allow us to infer causation from correlation, proving the common refrain not entirely accurate: statistics CAN be used to prove causality! Including: Reichenbach's principle, common causes, feedback, entanglement, EPR paradox, and so on.
REFERENCES:
Causal Discovery Algorithm in Quantum Mechanics Paper: https://arxiv.org/pdf/1208.4119.pdf
Causal Models overview (Quantum and Classical): https://arxiv.org/pdf/1609.09487.pdf
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

Добавлена

3 years ago

Watch the MinuteEarth video here – I PROMISE it's really really really good: https://www.youtube.com/watch?v=pAI1N96t8Vk
MinutePhysics & MinuteEarth are on Patreon: http://www.patreon.com/minutephysics and http://www.patreon.com/minuteearth
This video is about the differences between the corpses or final degenerate dense star forms that dead stars take: black holes, neutron stars, and white dwarfs. The main distinguishing features between them are the mass cutoffs (Chandrasekhar limit and Tolman-Oppenheimer-Volkoff Limit), the matter that makes them up (electrons, protons, neutrons, singularity?), and what holds them up against gravity – not thermal pressure from nuclear fusion like in a star like the sun, but electron or neutron degeneracy pressure (fermi pressure/pauli exclusion principle), and the strong nuclear force, and... nothing (in the case of a black hole).
REFERENCES:
Chandrasekhar Limit: https://en.wikipedia.org/wiki/Chandrasekhar_limit
Tolman-Oppenheimer-Volkoff Limit: https://en.wikipedia.org/wiki/Tolman–Oppenheimer–Volkoff_limit
Richard Pogge (Ohio State) on Neutron & White Dwarf Stars: http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit3/extreme.html
Richard Pogge on Star Formation: http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit2/starform.html
Richard Pogge on Black Holes
Differences between galaxies and galaxy clusters: https://www.newscientist.com/article/dn20026-when-is-a-group-of-stars-not-a-galaxy/
Introductory/review Paper on Neutron Stars: https://arxiv.org/pdf/1102.5735.pdf
White dwarf stars on hyperphysics: http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/whdwar.html
Brown Dwarf: https://en.wikipedia.org/wiki/Brown_dwarf
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

Добавлена

3 years ago

$2000 Anker Contest Link: http://bit.ly/2u5YUqb
Link to the PowerCore+ 26800 (the one I showed in the video): http://amzn.to/2vwh9Jr
Real Engineering's video: https://youtu.be/ahxBbEwhIE0
Sam and Niko channel: http://www.youtube.com/samandniko
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
Can Batteries Power Everything? This video is about the physical and chemical limitations to electrolytic batteries, and how we might surpass the energy density and specific energy of lithium-ion batteries (like the Panasonic 18650 batteries used in the Tesla Model S, for example).
REFERENCES:
Lithium Fluorine Hydrogen NASA Rocket fuel test: https://archive.org/details/nasa\_techdoc\_19700018655
Limits on Cell Potential of Batteries: https://en.wikipedia.org/wiki/Electrochemical_cell
Lithium Ion Batteries: https://en.wikipedia.org/wiki/Lithium-ion\_battery
Standard Electrode Potential for Lithium, Lithium Graphite, etc: https://en.wikipedia.org/wiki/Standard\_electrode\_potential\_(data\_page)
Trends in Gravimetric Energy Density (Specific Energy): https://www.researchgate.net/figure/255748970\_fig1\_Fig-3-Trend-of-capacity-and-energy-density-increase-in-18-650-cylindrical-type-Li-ion
Elon Musk/Telsa on why Lithium-ion is not exactly a lithium battery: http://benchmarkminerals.com/elon-musk-our-lithium-ion-batteries-should-be-called-nickel-graphite/
Lithium Sulfur Problems: http://www.sciencedirect.com/science/article/pii/S0378775312019568?via%3Dihub
https://www.researchgate.net/publication/225512575\_Lithium-sulfur\_batteries\_Problems\_and\_solutions
Supercapacitors: http://www.electronicdesign.com/power/can-supercapacitors-surpass-batteries-energy-storage
Panasonic 18650B Battery specs: https://na.industrial.panasonic.com/sites/default/pidsa/files/ncr18650b.pdf
Anker PowerCore+ 26800 disassembled: https://www.youtube.com/watch?v=qJS3m\_CGbeY
Types of Lithium Ion Batteries: http://batteryuniversity.com/learn/article/types\_of\_lithium\_ion
Batteries & Electrochemical Cells on Hyperphysics: http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/electrochem.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

Добавлена

3 years ago

A collaboration with Jorge Cham and Daniel Whiteson, check out "We Have No Idea" at http://www.wehavenoidea.com
Jorge's PhDComics: http://www.phdcomics.com
Numberphile video about sports in hyperbolic space: https://www.youtube.com/watch?v=u6Got0X41pY
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 the local and global geometry and curvature of space and spacetime, aka, is space flat? Negatively curved? Positively curved? etc.
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Добавлена

3 years ago

Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
This video is about why it's harder to successfully land spacecraft and landers and rovers on Mars than on Earth, or Venus, or the Moon, or Titan, or asteroids. It all comes down to atmospheric density! When there's no atmosphere, you can do a powered descent in a flimsy tinfoil spacecraft like the Lunar Module, and when there's plenty of atmosphere you can do an unpowered descent via heat shield and parachutes like the space shuttle, Apollo command module, Soyuz, Huygens, etc. But on Mars with its thin air, you have to do both powered & unpowered descent, getting the worst of both worlds.
Thanks to Hoppy Price from JPL for fact-checking this video!
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
REFERENCES
Spreadsheet to calculate landing success rates: https://docs.google.com/spreadsheets/d/1jqeZCG56UBKvd\_wsyW3GD-qd9TAsaW1RPAiZ-1BCUaE/edit?usp=sharing
NASA Low Density Supersonic Decelerator Fact Sheets: https://www.nasa.gov/pdf/737628main\_Final\_LDSD\_Fact\_Sheet\_3-26-13.pdf
https://www.jpl.nasa.gov/news/press\_kits/ldsd.pdf
LDSD Test Footage: https://www.nasa.gov/mission\_pages/tdm/ldsd/videos.html
More LDSD Test Footage:https://www.youtube.com/watch?v=lJzeeYoLn50
List of Missions to Mars: https://en.wikipedia.org/wiki/List\_of\_missions\_to\_Mars
List of Missions to the Moon: https://en.wikipedia.org/wiki/List\_of\_missions\_to\_the\_Moon
List of Missions to Saturn: https://en.wikipedia.org/wiki/Exploration\_of\_Saturn
List of Missions to Venus: https://en.wikipedia.org/wiki/List\_of\_missions\_to\_Venus
Curiosity Rover Landing Overview: https://mars.nasa.gov/msl/mission/technology/insituexploration/edl/
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

Добавлена

3 years ago

Thanks to Skillshare for supporting this video: http://skl.sh/MinutePhysics for 2 free months!
This video is about a multistable perceptual illusion, similar to the hollow face illusion, whereby maps or aerial or satellite photos look upside down/inside out, ie, concave (valley) parts look convex and convex (mountainous) parts look concave. Just flip the images around and things will make a lot more sense! It's just because our eyes gauge depth based on the location of shadows, and the sun always casts shadows on the bottoms of things.
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
REFERENCES
Twitter posts:
https://twitter.com/Astro2fish/status/859799730565414912
https://twitter.com/BadAstronomer/status/859800278358528001
Bad Astronomy Blog post: http://blogs.discovermagazine.com/badastronomy/2010/05/19/a-lunar-illusion-youll-flip-over/
Multistable perception http://en.m.wikipedia.org/wiki/Multistable_perception
Top-left Lighting http://en.m.wikipedia.org/wiki/Top-left_lighting
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Добавлена

3 years ago

Thanks to the Heising-Simons Foundation for supporting this video: http://www.heisingsimons.org
CRAZY Double Pendulum Footnote: https://youtu.be/gbJYK7q5ejY
Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
This video is about the phenomenon of neutrino oscillations, which is where neutrinos can change flavors (ie, change between electron, muon, or tau neutrinos) because those interaction states are in non-trivial superpositions of the free traveling/mass eigenstates (𝜈1, 𝜈2 and 𝜈3).
MinutePhysics is on twitter - @minutephysics
And facebook - http://facebook.com/minutephysics
And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6
REFERENCES
History of Neutrino Oscillations: https://arxiv.org/pdf/hep-ph/0610064.pdf
Solar Neutrino Problem: https://en.m.wikipedia.org/wiki/Solar_neutrino_problem
Neutrino Oscillation on Wikipedia: https://en.wikipedia.org/wiki/Neutrino_oscillation#Propagation_and_interference
Current best fit data for the mixing of neutrinos: http://www.nu-fit.org/?q=node/139
Neutrino Mixing Matrix: https://en.wikipedia.org/wiki/Pontecorvo–Maki–Nakagawa–Sakata_matrix
Neutrino Oscillation https://profmattstrassler.com/articles-and-posts/particle-physics-basics/neutrinos/neutrino-types-and-neutrino-oscillations/
Neutrino Masses paper: https://arxiv.org/pdf/1307.3518.pdf
Neutral Particle Oscillation: https://en.wikipedia.org/wiki/Neutral_particle_oscillation
Technical Intro to Neutrino Mass Mixing: http://pdg.lbl.gov/2015/reviews/rpp2015-rev-neutrino-mixing.pdf
PROSPECT project: http://prospect.yale.edu/science
Neutrino/nucleon deep inelastic scattering: https://www.nevis.columbia.edu/ccfr/index.html
Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich

Добавлена

3 years ago

A footnote to the video about Neutrino Shape-Shifting: https://youtu.be/7fgKBJDMO54
Sixty Symbols Video on Double Pendulum: https://www.youtube.com/watch?v=izy4a5erom8
Physics of The Double Pendulum: http://www.theorphys.science.ru.nl/people/fasolino/sub_java/pendula/doublependul-en.shtml
Neutral particle oscillation (like neutrino oscillation) is a superposition effect, and a similar effect can also be seen in a coupled double pendulum system where the interaction states are in superpositions of the "free" modes (called eigenstates).
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

Добавлена

3 years ago

This video is a footnote for the video about the ring around the earth: https://www.youtube.com/watch?v=4xSPlQUejd8
Essentially, a ring around the earth is in unstable equilibrium, so it would stay put, but then fall one way or the other as soon as any asymmetry (even thermal or quantum fluctuations) developed.
MinutePhysics is on Google+ - http://bit.ly/qzEwc6
And facebook - http://facebook.com/minutephysics
And 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

Добавлена

3 years ago

Thanks to http://www.squarespace.com/minutephysics for sponsoring this video; you can use offer code MINUTEPHYSICS at checkout for 10% off your first purchase.
Link to Patreon Supporters: http://www.minutephysics.com/supporters/
This video is about what would happen if we built a giant ring around earth – what would happen to the ring, that is. Would if fall? Collapse? Start spinning?
REFERENCES:
Why Isn’t It Faster to Fly West? Video https://www.youtube.com/watch?v=3gNkgj9h2oM
Physics Girl Quarter Shrinking: https://www.youtube.com/watch?v=d2TDXKfBaMQ
Symmetry Breaking: https://en.wikipedia.org/wiki/Symmetry_breaking
Forces through gauge symmetry: https://www.youtube.com/watch?v=9Uh5mTxRQcg
Higgs Boson: https://www.youtube.com/watch?v=9Uh5mTxRQcg
MinutePhysics is on Google+ - http://bit.ly/qzEwc6
And facebook - http://facebook.com/minutephysics
And 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

Добавлена

3 years ago

Support MinutePhysics on Patreon: http://www.patreon.com/minutephysics
Aatish Bhatia helped write this video! A big thanks for his help! Here's his blog: http://www.empiricalzeal.com
The universe is expanding – this we know from looking at red shifts of distant galaxies – but the acceleration of the universe's expansion is harder to measure. It requires measuring the change of recession velocity over time, and it's done by comparing Type Ia supernovas as standard candles at different distances, which is how we know the universe is accelerating!
Thanks to everyone who supports MinutePhysics on Patreon!
Link to Patreon supporters here: http://www.minutephysics.com/supporters.html
REFERENCES
Type Ia supernovae
http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/snovcn.html
https://en.wikipedia.org/wiki/Type_Ia_supernova
Luminosity Distance
https://en.wikipedia.org/wiki/Luminosity_distance
Hubble diagram for type Ia supernovas (relatively close to earth): http://www.pnas.org/content/101/1/8/F3.expansion
http://www.astronomy.ohio-state.edu/~thompson/1101/lecture_fate_of_universe.html
Straightforward references:
Ryan Foley talking about WFIRST & Dark Energy
https://youtu.be/BhOAwXYKdmw?t=23m
Dark Energy FAQ:
http://www.preposterousuniverse.com/blog/2011/10/04/dark-energy-faq/
Why does dark energy make the universe accelerate?
http://www.preposterousuniverse.com/blog/2013/11/16/why-does-dark-energy-make-the-universe-accelerate/
David Spergel on dark matter & WFIRST
https://tvr2c.com/2016/06/01/53116-show-feat-professor-david-spergel-on-his-research-spanning-astrophysical-scales/
Slightly-technical references:
Permlutter article (old article but quite well explained & goes into future directions near the end)
http://supernova.lbl.gov/PDFs/PhysicsTodayArticle.pdf
Technical references:
Mukhanov’s Physical Cosmology
http://www.astro.caltech.edu/~george/ay21/readings/Mukhanov_PhysFoundCosm.pdf
Nobel Prize Summary
http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/advanced-physicsprize2011.pdf
Cosmological redshift
https://en.wikipedia.org/wiki/Redshift#Expansion_of_space
MinutePhysics is on Google+ - http://bit.ly/qzEwc6
And facebook - http://facebook.com/minutephysics
And 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

Добавлена

3 years ago

There's a March for Science happening all over the world: http://marchforscience.com
This is a video about how science is both inherently political and apolitical. And how hopefully we won't end up in nuclear war...
REFERENCES:
Language acquisition and age of arrival:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813069/
https://www.utdallas.edu/~assmann/hcs6367/marinova_todd_marshall_snow00.pdf
National Academies of Sciences report on GMOs: http://nas-sites.org/ge-crops/2016/05/16/report-in-brief/
Gravitational time dilation: https://www.uam.es/personal_pdi/ciencias/jcuevas/Teaching/Chou-Hume-Rosenband-Wineland-Science2010.pdf
MinutePhysics is on Google+ - http://bit.ly/qzEwc6
And facebook - http://facebook.com/minutephysics
And 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

Добавлена

Loading...

## Воспользуйтесь вашим социальным профилем для входа