A Physics Prof Bet Me $10,000 I'm Wrong
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A UCLA Physics Professor bet me $10,000 that my video about going downwind faster than the wind was wrong. This video is sponsored by Brilliant. The first 200 people to sign up via brilliant.org/veritasium get 20% off a yearly subscription.

For more information about the Veritasium Science Communication Contest check out -- ve42.co/contest

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The wager agreement: ve42.co/wager

Prof. Kusenko's slides: ve42.co/Kusenko

My rebuttal: ve42.co/rebuttal
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Huge thanks to Xyla Foxlin for building the model cart, and making the instructions so accessible to the public. Check out Xyla's video -- uzmilk.info/number/jbudwqB_q2l2n88/video.html

A massive thanks to Bill Nye, Neil DeGrasse Tyson, and Sean Carroll for witnessing the signing of the wager.

A huge thanks to Prof. Alexander Kusenko for being a man of honour -- it's a difficult thing to change your mind, especially in a public forum.

A huge thanks to Prof. Mark Drela for the interview and help making sure we got the physics right.

A massive thanks to Rick Cavallaro for making Blackbird, all your insights, analysis, data, and general help with these videos -- it was so fun to work with you on this crazy project -- check out Rick's channel ve42.co/Rick

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References
M. Drela. Dead-Downwind Faster Than The Wind (DDWFTTW)
Analysis (Jan 2009) -- ve42.co/Drela

2013 AAPT United States Physics Olympiad Semifinal Exam -- ve42.co/AAPT2013

Rick's treadmill footage -- ve42.co/Treadmill

Rick's multiple explanations of how Blackbird works -- ve42.co/DDWFTTW

Blackford, B. L. (1978). The physics of a push‐me pull‐you boat. American Journal of Physics, 46(10), 1004-1006. - ve42.co/Blackford1979

Ruina corrects errors in the above paper: ruina.tam.cornell.edu/research...

Forum discussions -- ve42.co/forum Blog -- ve42.co/blog1 and retraction ve42.co/BlogRetraction

Bauer, A. B. (1969, April). Faster than the Wind. In First AIAA Symposium on Sailing. -- ve42.co/Bauer1969

Bauer's Obituary -- ve42.co/BauerObituary

Gaunaa, M., Øye, S., & Mikkelsen, R. F. (2009). Theory and design of flow driven vehicles using rotors for energy conversion. In EWEC 2009 Proceedings online EWEC

Md. Sadak Ali Khan, Syed Ali Sufiyan, Jibu Thomas George, Md. Nizamuddin Ahmed. Analysis of Down-Wind Propeller Vehicle. International Journal of Scientific and Research Publications, 3, 4. (April 2013) ISSN 2250-3153.


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Special thanks to Patreon supporters: Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Bill Linder, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim Buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal

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Written and Edited by Derek Muller
Animation by Mike Radjabov
Manim equations by Jonny Hyman
Filmed by Emily Zhang and Raquel Nuno
Music from Epidemic Sound epidemicsound.com and by Jonny Hyman
Additional video supplied by Getty Images
Produced by Emily Zhang, Petr Lebedev and Derek Muller

Fikrlar
  • Johnson musik
    Johnson musik

    Dope af man sheeeees 🔥❤️🔥

  • Johnson musik
    Johnson musik

    Just waow man, u really are legend

  • ployter94
    ployter94

    So this was more of an illusion, thinking that the propeller was the key source of the movement.

  • John Bobby Jackson
    John Bobby Jackson

    Bill and neil are kinda just figureheads tho

  • agmc4me
    agmc4me

    The problem is there are to many people like him

  • ryan west
    ryan west

    Props to professor Alex for his behaviour - this is a very unintuitive problem and his explanations make a lot of sense. I had little idea what to make of things for a while there.

  • Jeff Sidlosky
    Jeff Sidlosky

    Heck yeah, I am glad you won and it makes sense. I am disappointed the professor and also Bill Nye and Neil didn't come back on video to talk about it afterwards. Seems like the physics professor might have possibly been embarrassed.

  • Jeff Huffman
    Jeff Huffman

    Why would you have those HACKS verify anything?

  • Chelt munt 420
    Chelt munt 420

    Your a fool. You could have had wind socks the whole test strip BUT THAT WOULD HAVE PROVED YOU WRONG WITHOUT A DOUBT.

  • Chelt munt 420
    Chelt munt 420

    If the "fan" is actually doing what you thought then it would pull the string on a stick back into the fan. Thus making you a cheater

  • ol102jg
    ol102jg

    i watched both videos and in both videos the correct answer is given, but it is not the one they concluding, the propeller doesn't work as a fan, in a treadmill model it does work as a fan it is pushing air backward, but in "desert" model it works as a sail. and it has higher ground speed in comparison to air speed because propeller coupled directly to the wheels thru' a gear. in the true experiment in my opinion propeller should be decoupled from the wheels and only propeller blade angle can vary and be adjusted while in motion.

    • Rick Cavallaro
      Rick Cavallaro

      The kinematics and aerodynamics are identical for the Blackbird and the treadmill models. And neither one will work with the propeller disconnected from the wheels.

  • Kai Yan
    Kai Yan

    Physics Olympiad is not the same as regular physics

    • Rick Cavallaro
      Rick Cavallaro

      I'm pretty sure they use the same laws of physics we use in the rest of the universe.

  • Pixel-Tree Gaming!
    Pixel-Tree Gaming!

    it would be nice to call bill anytime haha

  • Business Aviation Crew Channel
    Business Aviation Crew Channel

    If you are a professor, you should know how to build an experiment scheme and take into account all the acting forces and features of the scheme, including the peculiarities of the change in wind speed along the height and its gusts. Based on all these factors, taking into account the design of the object of the experiment itself, it is possible to assume that the speed of the trolley may be more likely. All these actions must be done prematurely to argue for 10,000 USD. Of course, if your name as a professor is important to you and 10,000 USD is a significant amount. Someone does not earn that kind of money in a year!

    • Business Aviation Crew Channel
      Business Aviation Crew Channel

      @Rick Cavallaro Money is important, but is number 2. The name of the professor as a professional and the expert who is unable to understand and make scientific calculations in relatively quite simple experiment looking from the professor’s status is quite strange. Secondly is payment even 100 USD looks as a playing in casino and isn’t showing the person as a scientist! It should be a scientific dispute with an appropriate evidence scientific basis, not a game of money.

    • Rick Cavallaro
      Rick Cavallaro

      Kusenko earns that money in a month.

  • Skwrl Fuzz
    Skwrl Fuzz

    Honestly, if the Prof entered the wager knowing as little as we did at the beginning of the video, then it was unfair. I had no idea that the prop was connected to the wheels. lol

    • Rick Cavallaro
      Rick Cavallaro

      Everything you could hope to know about this vehicle is available and easily found on-line - including all the rules and raw data from the world record runs. And I'm absolutely certain Derek was willing to show him and describe how it works. Alex didn't want to hear it - so this is on him.

    • Jeff Sidlosky
      Jeff Sidlosky

      He knew, he saw the previous video which explained that clearly.

  • João Rebelo Rodrigues
    João Rebelo Rodrigues

    Awesome video man!!! I loved all about it.

  • LoneWolf Ryan
    LoneWolf Ryan

    Look for RATIO AND PROPORTION, in the turning of the fan and rear wheels.

  • Roberto
    Roberto

    sorry my ignorance, why they don’t build transportation systems to take advantage of this phenomenon? like a train system, maybe they did , like the boat? or simply a more static electricity generator?

    • J Modified
      J Modified

      It would only work while going downwind in a significant wind. In other cases, it would add losses. Even if you had an appropriate route to use it, the vehicle is quite impractical. For a static generator, a stationary windmill works much better.

  • Norm Dickson
    Norm Dickson

    Rotation of mass is helping you here I believe you win in this case

    • John Borton
      John Borton

      Nope. It's 100% wind powered.

  • Norm Dickson
    Norm Dickson

    I no why it goes faster than the win Rotation of mass and the force trying to pull the prop off

  • Edward Baker
    Edward Baker

    that treadmill thing is cracking

  • freedomsteppa
    freedomsteppa

    Oh shoot, don't put it to rest! This should only mark the beginning!

  • Cody Haddican
    Cody Haddican

    Having Bill Nye involved is pointless he's an idiot... And more an actor and not a scientist..... 😂

    • Rick Cavallaro
      Rick Cavallaro

      Yeah - all the anti-science folks seem to think so.

  • Self Actualizer
    Self Actualizer

    If you are going the same speed as wind theoretically you could go as fast as he says. Yes, But, wouldn't the force of gravity, friction from air particles, etc, stop that from happening

  • Jacob Taylor
    Jacob Taylor

    Bill nye is an idiot and shouldnt have been invited in my opinion. The mans been bullshitting ever since he got his title on a news broadcast, someone said “who do you think you are, bill nye the science guy?” And it stuck, i dont think he actually has any physics or science degrees. Everytime he opens his mouth to “add onto the conversation” he just says the most bland unscientific information and you can see in neils face like why tf are you trying to explain it

    • Rick Cavallaro
      Rick Cavallaro

      I know for a fact that Neil has a lot of respect for Bill. It's only the anti-science crowd that doesn't.

  • Kenny Westone
    Kenny Westone

    Bill Nye isn't even a scientist, but a charlatan who denies logic.

    • Rick Cavallaro
      Rick Cavallaro

      Says the guy that denies science.

  • Chris Nguyen
    Chris Nguyen

    You won on this double energy conversion design, but if you have a pure wind-energy using propeller design, you would lose this bet.

    • Rick Cavallaro
      Rick Cavallaro

      @J Modified Yeah - but this is "DOUBLE ENERGY". Weren't you paying attention!? :)

    • J Modified
      J Modified

      @Chris Nguyen All the energy comes from reducing the speed of the air and earth relative to each other. It is purely wind powered.

    • Chris Nguyen
      Chris Nguyen

      @John Borton not actually: The propeller did push the car at first by the wind like a sail not propeller, the propeller in turn is speed up by the wheels on the ground. With proper design, the wheels will spin the propeller faster, which will produce force backward in combination of the force forward by the win, now it is a propeller. This is double energy. Not a flywheel but using the flywheel idea. The original Blackbird design explains pretty much of this conversion, if you read it carefully.

    • John Borton
      John Borton

      The Blackbird is a pure wind-energy using propeller design.

  • Mister Baer
    Mister Baer

    Best follow up video ever

  • Joseph Wendt
    Joseph Wendt

    Respect on his name. No one challenges Veritas

  • LBCAndrew
    LBCAndrew

    Would this have anything to do with how sailboats can move faster than the wind speed? And by a lot at times. On June 18th 2013, the Emirates Team New Zealand recorded a speed of 50.8mph with a wind speed of 18mph. In sailing, there are two types of wind. True wind, and apparent wind. The former pushes the sailboat forward, and the latter drags it forward. This is achieved by traveling at an angle to the wind while the sail is perpendicular to it. As for your video, it would have been far more enjoyable to watch without that bigot Neil Degrasse Tyson who blames everything he can think of on racism. My favorite were how he used to get pulled over by police a lot and of course blame it on systemic racism. I used to get pulled over even more frequently than he did, and never ticketed. Just harassed, had my car searched without any probable cause multiple times, and so they could just ask stupid questions. In some of his pull overs, he did things like not signal. In over a dozen pull overs for me, not a single law broken other than i guess being white.

    • Rick Cavallaro
      Rick Cavallaro

      >> The former pushes the sailboat forward, and the latter drags it forward That's not how it works. Wind over an airfoil is wind over an airfoil. Under normal circumstances it will create a lot of lift and a little drag.

  • Mahesh Adhikari
    Mahesh Adhikari

    So what's the ideal maximum?

  • Joshua Rain
    Joshua Rain

    Good for you

  • JC Alpha
    JC Alpha

    This is amazing! Thank you!

  • Daniel Ramirez
    Daniel Ramirez

    I still I'm reluctant. At the beginning you said "...faster than the wind it's pushing it...", well, if it is like a sail (meaning the air starts pushing it), how come the propeller works like a fan?! It either is like a sail or a fan, it can't be both. So, what's pushing the vehicle at the beginning if the propeller it's a fan?

    • John Borton
      John Borton

      // "...what's pushing the vehicle at the beginning if the propeller it's a fan?"// Initially, it's merely the bluff body drag of the device carrying it downwind - just like say a tumbleweed. The Blackbird is designed to operate in a 10-15mph wind and about 1/2 windspeed, the tips of the airfoils start to come unstalled and generate a bit of thrust. By about 3/4 WS, the entire blade goes to work.

  • James Aspinwall
    James Aspinwall

    You kept me on the edge of my seat. Please, add a link to your Patreon support page. I had to re-search (yes, this is the second time) in Patreon to find you and increase my pledge. Thanks Bill Nye, Neil DeGrasse Tyson, and Sean Carroll for keeping science honest.

  • Rÿtch Bÿtch Rocking Club
    Rÿtch Bÿtch Rocking Club

    I probably missed something due to the language (I'm not an english native), however I don't understand how - if the propeller is a fan driving the air - the whole movement STARTS. Does the pilot have to start the vehicle e.g. like a bike and then it takes over, or does the fan indeed start TAKING energy from the wind and then at asome point "switch mode" and DRIVE out air instead? When I try to imagine the needed angle of the blades, then it seems to me that this latter mode of operation wouldn't work - the circular motion of the propeller would have to revert its direction to do so, which it obviously doesn't do. So - is there some "ignition energy" needed to start the whole thing?

    • Rÿtch Bÿtch Rocking Club
      Rÿtch Bÿtch Rocking Club

      @Rick Cavallaro Ahh cool I get it. Yeah, variable pitch makes sense! Thanks for the quick response!

    • Rick Cavallaro
      Rick Cavallaro

      First of all, your English is better than 90% of native English speakers I encounter. Secondly, you ask a great question. I'll do my best to answer it... The cart starts because the tailwind simply pushes on it (body and propeller) from behind as a bluff body. This of course causes the wheels to turn, and they cause the propeller to turn. As we approach wind speed the tips of the propeller begin to develop attached flow and therefore generate lift (or thrust in this case). The faster we go, the more that attached flow works its way along the blades until the whole propeller is operating exactly like that of the propeller on the front of a Cessna. The tricky part is that the wind from behind is trying to turn the prop counter-clockwise while the wheels are trying to turn it clockwise. The trick is that the blade pitch must be below a critical angle such that the wheels win the battle for turning the prop. Initially we had a fixed pitch prop, and it was that simple. We then made the propeller variable pitch so we could optimize pitch along the run. So now we start with a very flat pitch, and increase the pitch as we pick up speed.

  • Hillel Weiser
    Hillel Weiser

    Yeah but the problem with this that the propellers are angled, if it would be flat against the wind it would never go faster than the wind,

    • Rick Cavallaro
      Rick Cavallaro

      The propeller is angled or the blades are "angled"? Propellers have pitch. That's what makes them propellers.

  • Thomas Robertson
    Thomas Robertson

    Yes I can understand. Why and how that .they made .the Wind mill as it was

  • Waleed Qadi
    Waleed Qadi

    But i guess we have a problem here, as i understood from the video the professor was betting that the car can't go faster than the wind with only the propeller pushing it, and also as you mentioned in the video (7:15) you didn't "do a good enough job explaining how it works", then in this video you just explained that the wheel is connected to the propeller and the propeller and wheels are working like a transmission system then that made sense, for me this whole bet is not valid anymore as both of you are betting on two different things, it's just like betting if a sailboat can go faster than the wind (which should be as the professor explained) then you come and install a jet engine to the sailboat to claim that the sailboat can go faster than the wind speed!. Anyway the whole bet thing is good for the channel as exposer and media reach, but honestly i see it as misleading for the audience specially that we are talking about science here and the bet itself is not meeting the proper scientific requirements !

    • Waleed Qadi
      Waleed Qadi

      Yes you are right, i didn't notice the document before, my bad

    • John Borton
      John Borton

      Read the wager agreement. You misunderstand the bet.

  • Darian wuz here
    Darian wuz here

    Bill Nye pretending he knows whats going on

    • Rick Cavallaro
      Rick Cavallaro

      Science deniers pretending he doesn't

  • Philip Drew
    Philip Drew

    This is so dumb, its just the fluid dynamics around the airfoil is not drag of a sail. Its less drag than a sail of the same dimensions. It should be flippin solvable to any high ranking physics proffessor. Edit: You didn't even answer why this ^ is why

  • Brock Logan
    Brock Logan

    So, now we just need to figure out how to do with this light :)

  • YaNykyta
    YaNykyta

    You are all crazy :))) Together with Xyla! :))) O. M. G. !!!

  • Luis Garcia Garcia
    Luis Garcia Garcia

    Who won?

    • Rick Cavallaro
      Rick Cavallaro

      There's simply no way to ever know

  • MinKook DaeHan
    MinKook DaeHan

    It would be better to draw a distance(time-line) graph to illustrate the speed of the winds, the speed of the car, the RPM of the propeller, and the forces. People are interesting in three things: 1. the moment when the speed of wind and the speed of the car are the same. 2. the increment of the car's speed after the moment; how long does the car move faster than the wind? 3. a design to make the road a cylinder road, so the car can move forever.

    • Rick Cavallaro
      Rick Cavallaro

      @MinKook DaeHan You're more confused than I thought. But thanks very much for trying to correct me on how my cart works.

    • MinKook DaeHan
      MinKook DaeHan

      >> After the car passes the moment, the car was accelerated by the propeller, not by wind. >>>>It's still wind powered, but now the propeller is generating the thrust to keep it going faster than the wind. No, there is no relative wind against the propeller when the car passes at that moment. Only the rotating propeller pushes the air to make the car move forward. In that moment, it works like a propeller-powered airplane. When the car runs faster than the wind, there is a relative headwind like the propeller bumping with air particles. >> We need #3 for the acceleration on the big cylinder road. You will know the reason later. Don't worry. I don't want to tell the detailed reason here. Someday someone will make it and explain the reason. 😊😊

    • Rick Cavallaro
      Rick Cavallaro

      @MinKook DaeHan Before we reach wind speed the cart experiences a relative tail wind. At wind speed the cart experiences 0 relative wind. When we pass wind speed, the cart feels a relative headwind. >> After the car passes the moment, the car was accelerated by the propeller, not by wind. It's still wind powered, but now the propeller is generating the thrust to keep it going faster than the wind. >> We need #3 for the acceleration on the big cylinder road. You will know the reason later. 😊 Well I don't know how to make a real road into a cylinder and keep a 400 lb Blackbird on it, so I guess I'll never know why. You said "so the cart can move forever". But it can already move forever.

    • MinKook DaeHan
      MinKook DaeHan

      Even when the car passes the moment, what you say is the wind blows to which direction(?) After the car passes the moment, the car was accelerated by the propeller, not by wind. We need #3 for the acceleration on the big cylinder road. You will know the reason later. 😊

    • Rick Cavallaro
      Rick Cavallaro

      It will go faster than the wind for as long as the wind blows. No need for #3

  • David Turner
    David Turner

    I am no physics professor but it seems to me this is missing a big variable and that is volume of wind taken in by the propeller into a smaller refined area in the blades creating larger force. If you were to reduce the size of the blades you would see a loss in the net gain.

  • kooolman
    kooolman

    One thing I want to say This professor is genius, he not only admits but explains how he was wrong (which even the youtuber does not have a clue), which means he can learn far better technology than others, maybe when aliens come, this professor might be needed in the pentagon :D

  • Gary Shay
    Gary Shay

    So with one big propeller, this works. But such a large prop seems impractical. Would this work with multiple smaller fans as well? And would that increase the stability of a vehicle with fans driven by wheels on the opposite side? In other words, would a smaller fan in the left-rear attached to the wheel in the upper right and the right-rear fan driven by the front left achieve stable, uh, flight? Is the differential in the speed of the wheels when the vehicle turns enough to produce corrective force on the fans and still produce relative acceleration in the direction of travel?

  • Ben
    Ben

    Im curious why xyla's first prototypes failed and the last one did work

    • Ben
      Ben

      @coolaun thanks

    • coolaun
      coolaun

      Xyla explains it in the video she put on her channel, "Building the Vehicle Physicists Called Impossible".

  • Justin Jin
    Justin Jin

    The flawless windshield directly lick because milkshake oppositely risk per a mean block. ajar, callous picture

  • DrPastah
    DrPastah

    Niel & Bill, jesus christ this channel is done for.

  • Steve Warner
    Steve Warner

    Maybe should've been more specific in your wager?

    • Rick Cavallaro
      Rick Cavallaro

      Have you read the signed document? It was pretty specific, and Derek very clearly won.

  • Freedom Rises
    Freedom Rises

    Hi Can I claim that 10, 000 dollars now please. You are both wrong, on the real dynamic that cause the effect of a vehicle of that design showing increasing speed, even in any wind drops during the tests, was due to the following. This so called phenomena is due to the fact that the propellers , kinetic energy , and weight induced and excited , by the wind was the catalyst that caused the Propellers to operate as a FLYWHEEL, This is why the velocity of the vehicle ,could be maintained and even increase its speed during wind drops. I could use that money more constructively to experiment , on Flywheel driven home generators operating on a pulse system, and the Kinetic energy from FLYWHEELS where overunity certainly exists, in a pulse and and Kinetic energy construct for that purpose. So when you contact me I will give you the details to send it to. Thank you.

    • John Borton
      John Borton

      @Freedom Rises // " I am not a betting man"// So you want people to just give you $10,000 for being wrong? Not how the world works.

    • John Borton
      John Borton

      @Freedom Rises // "Am sure the interested public,"// All explained in the video -- remember that attention span issue of yours I referenced?

    • John Borton
      John Borton

      @Freedom Rises // "yours is 10 seconds."// Given that Rick and I designed and built the Blackbird from scratch and you didn't manage to pay attention to the first 20 seconds of the video, your response is nonsensical.

    • Rick Cavallaro
      Rick Cavallaro

      @Freedom Rises >> I am not a betting man I see. So you're just looking for a $10K donation. Good luck with that. >> What you could do , though is put your mouth where you think your brain is operational in this matter. As compelling as it is to answer an insulting anonymous troll, I think I'll just invite you to find where I've already answered that 100 times in these comments.

    • Freedom Rises
      Freedom Rises

      @Rick Cavallaro I am not a betting man and have no sum anyway to match that , to give to a independent referee. What you could do , though I propose is that instead of bringing bringing money into a open source debate. In the Showman fashion it evolved from . That you present why you think the propellers are not acting as a FLYWHEEL, and what you believe is the cause of the phenomena , in question on this matter. This being in your opinion that the propeller, is not acting as a FLYWHEEL in making the vehicle in question increase speeds , when the winds drops in the course of it's time on the test path in question. Because ..................................................................................................................................................................................................................... ...................................................................................................................................................................................................................................... Please fill in above. Am sure the interested public, as much as I would appreciate your reply and input on this matter.

  • Asadbek Khudayberganov
    Asadbek Khudayberganov

    Scientist do different stuff in the gym than exercising

  • Hazbin Hotel
    Hazbin Hotel

    Two coupled rotationals where r1 doesn't equal r2 and your telling me you can build an infinite fibonacchi esqe series mechanically? Who knew...;') LOL.... this is kinda hilarious. Gee grrr geersssrrhhh dag nabit he's a built a darn perpetual motion TIME MACHINE! !!!!!!!

  • Hazbin Hotel
    Hazbin Hotel

    ohhh Im sorta a time feild theorist and..geeeee what is happening is kinda related.... Veritasium is gonna win...even if the frequency resonance patterns of say the tread mill or air turbulence or rotational pressure differentials are to blame... eee hee heee... Um DUH!!!!! That's called winning! That's just sorta how you do it in order to win.

  • Losay Impang
    Losay Impang

    gears :)

  • enilenis
    enilenis

    Imagine a rope with a weight going over a pulley. You lift the pulley up and it raises the weight. The weight goes up by twice as much as you're raising the pulley. If you do multiple loops of the rope between 2 pulleys, you can trade force for distance, and achieve multiples of the input velocity. Your projectile seemingly moves faster than you're "pushing" it.

  • Cody Hildebrand
    Cody Hildebrand

    Isn't this all the same as pulling a spool of string toward you?

    • coolaun
      coolaun

      Basically yes. In both cases a linear input produces an output that is faster than the input and in the same direction. I think many people who don't understand what is going on here could benefit from experimenting with a spool of thread.

  • Queen Ants
    Queen Ants

    Put a low string and a high string at the front all together and we will see if all two of them will be the same.

    • subductionzone
      subductionzone

      It has been done. It was already known that this cart did work. It was a foolish bet by the professor. I can link a video with several streamers on it. One above the cart, two at the same height as the propeller, but off to the side so that they are not affected by the propeller, and one in front. The one in front both shows whether it is going faster than the wind there and makes the pilot able to steer the cart directly downwind. If it veers off to the left or right he knows which way to steer to keep going directly downwind.

  • Maximilian Mander
    Maximilian Mander

    Cantylu also use the wind to power the wheels and the morewind is coming towards the car the faster the wheels would spin? So that : Wheelspeed = windspeed + speed of the car?

    • Rick Cavallaro
      Rick Cavallaro

      That pretty much describes how the Blackbird works when configured to go directly into the wind. We set that record at 2.1X wind speed in 2012.

    • eyytee
      eyytee

      That would not work for going downwind faster than the wind in steady state, because it would speed up the air relative to the ground, instead of slowing it down. It would create more wind instead of extracting energy from it. See also 11:02: The power input must by the the higher relative speed (ground).

    • subductionzone
      subductionzone

      No, it would not work that way. You are describing a turbine and that cannot run faster than the wind. Or at least no one has come up with an innovative way to do so yet.

  • JOHN MURRAY ALFORD
    JOHN MURRAY ALFORD

    The downwind speed increase cannot be sustained. When the vehicle was travelling slower than the wind at first, inertial energy was being stored by the propeller and the mass of the vehicle. Then that stored energy was briefly used to propel the vehicle faster than the wind.

    • eyytee
      eyytee

      @JOHN MURRAY ALFORD Yes, you got it. See also 11:02 where this is visualized. The Blackbird does have multiple sprockets at the wheel axis, but cannot switch gears during a run, only between the runs. The variable pitch alone doesn't allow to use stored energy, because you still cannot slow down the propeller rotation when the vehicle accelerates.

    • JOHN MURRAY ALFORD
      JOHN MURRAY ALFORD

      @eyytee Thank you for your persistence in trying to educate me. I think I'm beginning to understand this concept and starting to see that even when the air-car is travelling faster than the wind it is still able to use the wind to accelerate it because it is blowing back against it, and the effective forward speed of the propeller part of the car (for Force X Distance energy transfer), is slower than the speed of the wheels (and the body) of the air-car (for F X D energy transfer), allowing the accelerating force of the propeller to be greater than the decelerating force of the friction on the wheels. It's a new idea to me, and I'm starting to conceive other possible devices that could use the same principle. (This no longer concerns me, but rewatching one of the videos, I noticed that the Blackbird air-car actually does have gears (not sure if they are used), and it does have a left-hand control for the driver to adjust the pitch of the rotating blades to maximize its acceleration.) Again, thank you.

    • eyytee
      eyytee

      @JOHN MURRAY ALFORD The energy source is the velocity difference between air and ground, which is being reduced by the vehicle. Your idea of energy stored in the blade distortion makes no sense, because that energy also increases with speed, as the forces on the blades increase. It is also absurd to expect that this amount of energy would accelerate the vehicle for over a minute, while it's above windspeed. Watch some other videos, not just Derek's short run.

    • JOHN MURRAY ALFORD
      JOHN MURRAY ALFORD

      @eyytee I suspect that the mysterious, unexplained source of energy comes from the energy contained in the distorted shape of the spinning propeller blades. The pitch of the spinning blades is stretched out of shape as the air-car accelerates up to wind speed (and the propeller rotation speed also increases), and once the propeller blades are allowed to start returning to normal shape as the air pushing on them from behind diminishes, then that stored energy in the flexed blade-pitch is what gives the extra push on the air to cause the faster-than-wind-speed acceleration of the air-car (for a limited time,) until the blades return to their normal, zero-speed shape, then no further acceleration can take place, only deceleration because the air-car is losing energy to the wheel friction on the ground, the headwind drag, and the air being blown backward. As soon as someone comes out with a bicycle that will travel into the wind by itself, indefinitely, then I'll buy one (and so will a billion other people).

    • eyytee
      eyytee

      @JOHN MURRAY ALFORD " has to be the stored kinetic energy of all the moving parts " Wrong. None of the moving parts are slowing down as the vehicle accelerates, so none of them is releasing stored kinetic energy. For correct energy analyses read the papers linked in the video description (AAPT, Drela, Gaunaa er al.)

  • MadStupid
    MadStupid

    This only serves to prove, that the "experts" who everyone expects you to believe because "they are the experts" can be wrong.

    • Rick Cavallaro
      Rick Cavallaro

      @MadStupid Despite all the shade Bill Nye is getting in these comments, he's a really sharp guy. It's true his real expertise is as a science communicator, but he's sharper than plenty of the engineers I've worked with. You should really check out his youtube debate with Ken Ham.

    • MadStupid
      MadStupid

      @Rick Cavallaro well, Kusenko certainly 'thinks' he's an expert, and convinced others. I will admit, knowing who is actually qualified to be considered an expert is equally important. Bill Nye immediately comes to mind...

    • Rick Cavallaro
      Rick Cavallaro

      That's right - the experts can be wrong. But it's always best to bet on them being right. In this particular case however, Kusenko is definitely not the expert. I'm unquestionably more expert than Kusenko in this area.

  • adrian plaskitt
    adrian plaskitt

    ***Edit...."My opinion" below was not worth a turd in a bucket! LOL - thanks for everyone who pointed out my errors - its all so dang counterintuitive! **** My opinion.Yes it goes faster than the wind. But the explanation is wrong. The key is in the ability to adjust the angle of attack of the blades of the fan/sail. Near wind speed it acts as a flywheel, smoothing out variations in wind gusts, and by adjusting the angle of attack the operator stores wind energy in the flywheel when a gust appears. That is why the inventors did not know which way to pull the lever to slow down when they were explaining the controls - it's because it varies moment to moment depending on the relative speed of the vehicle and wind. The key difference between the treadmill model and the real machine is the trimming ability. The treadmill analogy is very poor and misleading. You need to turn off the treadmill and put a fan behind the model. The treadmill model will stop as soon as the energy provided by the treadmill stops. It looks the same but is actually a completely different mechanism.

    • adrian plaskitt
      adrian plaskitt

      @subductionzone Thanks - that's really helpful....I was stuck in my thinking. All the best.

    • adrian plaskitt
      adrian plaskitt

      @J Modified yes, you are right. I was so blinded by thinking I knew what was happening that I was looking for reasons to ignore this basic fact. Thanks for pointing it out, and being so patient!

    • subductionzone
      subductionzone

      @adrian plaskitt The easy way to understand how it works is to look at the kinetic energy of the air that goes through the propeller and maintaining a constant frame of reference while one does so. From a ground frame of reference one can see that even when the cart is moving at the speed of the wind that the air that passes through the rotator disc is moving slower relative to the ground after it passes through the disc. That loss of energy by the air is the source of power for the cart. This difference in wind speed before and after exists at all speeds of the cart as it moves downwind. The Blackbird might need a bit of a tune up when it comes to some of its controls. It has been ten years since it was built. Rick got it up to roughly three times the speed of the wind. A bit over that in unofficial runs if I remember correctly. In the record run he was at 2.8 times the speed of the wind. In the videos of that one can see the propeller flexing forward as it exerts more and more force..

    • subductionzone
      subductionzone

      @adrian plaskitt Think of a bicycle. If you tie a rope to a pedal and lower it to its lowest position, get behind and pull on the pedal backwards the bicycle will still move forwards. That is just a matter of gear ratios. But I see that you get this finally. And yes it is counterintuitive as hell. That is what makes it an interesting topic.

    • J Modified
      J Modified

      @adrian plaskitt "If the propeller is connected to the wheels then it turns, providing thrust, but this force is balanced by the slowing the wheels". What makes you think those forces need to balance? Do the forces on two sides of a lever need to balance? If you really believe that then it must apply to the plank-powered car also. The only difference is how much the connection to the driving media can slip. "But the earth does not provide energy to a vehicle on it." Yes it does. In the reference frame of the wind, the earth powers the cart. This will accelerate the earth (decelerate it with respect to the air) by an extremely tiny amount. To keep the earth at an exactly constant speed, all else being equal, you would need to power the earth while the cart runs. You could do that by blowing a fan in the opposite direction. This is no different than the treadmill except for the relative scales. On a giant treadmill (or to use my earlier example, a ship moving in still air), the change in speed while the cart runs would also be insignificant without compensation from the motor/engine. Again, there is no way to tell the difference between air moving over a surface at constant speed and a surface moving at constant speed in still air without external cues. This is a basic fact of physics.

  • Mayur Sonawane
    Mayur Sonawane

    I love this channel!

  • The Denying Dutchman
    The Denying Dutchman

    I love how people are able to think outside the box and are able to prove their theory both in reality and equations. It is also a bit sad really, it makes me wonder how many ideas and potential inventions never saw the light of day because people were told it could not work.

  • therightone
    therightone

    That lever example was really helpful

  • MrDiagorasofmelos
    MrDiagorasofmelos

    Minus 10 000 U$D is indeed the salary that many of my teachers should have been paid. I I would have gladly given it all to the best teachers. The one that were committed.

  • Hey Sporto!
    Hey Sporto!

    Post number 1. Bill Nye is not a scientist- he believes men can give birth

    • subductionzone
      subductionzone

      @Hey Sporto! I will answer this once you own up to your error. Are you a man of honor or just a troll?

    • Hey Sporto!
      Hey Sporto!

      @subductionzone so can a man give birth? What's your belief?

    • Hey Sporto!
      Hey Sporto!

      @subductionzone really??? seriously?? and i quote "and even for people with just two sex chromosomes, hormones can vary wildly, so can anatomy, what makes someone male or female isn't so clear cut"...he used the word male and female- not man or woman.... you and i both know-what he means and you and i both know he isnt a real scientist- he is at best an engineer. ..and definitely not a biologist.

    • subductionzone
      subductionzone

      @Hey Sporto! Okay, I found a UZmilk video with that title, two minutes and thirty four seconds long. But he does not make that claim there. You may be conflating gender identity with sex. It is hard to say since at least in the video that I found he does not make the statement that you said that he did.

    • subductionzone
      subductionzone

      @Hey Sporto! Your posts 3 and 6 do not exist. They appear to be blocked. Can you still see them? You could always sign out and find your first post and see if all of your responses are there.

  • Kyle Trent
    Kyle Trent

    It makes sense with correct gearing

    • Rick Cavallaro
      Rick Cavallaro

      The treadmill models use 1:1 gearing. The Blackbird uses more than 2:1. The gear ratio by itself is really not terribly important.

  • Pork Chop
    Pork Chop

    i havent watched the whole video yet but i know sailboats can sail faster than the wind speed.

  • Perry James
    Perry James

    One of the very best educational sites to ever grace the internet...

  • DragonHawke Clouse
    DragonHawke Clouse

    also, after i typed the first comment out, in very short order, i realized, you just solved.....rather, you gave the FOUNDATION for faster than light travel.....if a "light-propeller" could be made, along with a special kind of "wheel" to move along the "fabric of space-time", this concept can cause "faster than light" travel.....FTL all laws are made to be broken, as, they are nothing more than man THINKING that "this is the way the universe works" i have 4 more ideas like this.....ground breaking, reality changing i just can't seem to get in touch with the right people i would love it if you contacted me

    • J Modified
      J Modified

      If you do the relativity calculations, something like the plank-powered toy will move faster than the board, but never faster than light. For example, if you have one that moves at 2x plank speed, that x multiple will decrease as the plank speed approaches light speed, with a limit of 1 at light speed (relative to an observer on the ground). The speed of light is not the kind of limit you're thinking of. It's more like "you can't travel north of the north pole on the surface of the earth". It's a built-in part of reality, not a barrier.

  • David Si
    David Si

    Storyteller. Dreamer. With such a mountain "Physicists" you can prove everything that you want and it is not surprising, something else to expect from the followers of relativism. When the screw rotates, it rotates the mass of the air around the screw and it creates additional energy to move, which is inevitably spent. With the same success, you could attach the time spring on the wheels, stock in it at a certain point and then pay at the right moment. Of course, at this moment, when the spring helps move along with the wind, the speed will be greater than the wind speed, but not for a long time. The same applies to the treadmill. The cart does not move when you keep it with your hand, but there is a traction, because the thrust through the gearbox is transmitted to the screw and it is natural. You make a treadmill ten times longest, then you will see that the cart does not catch the wind and go back along with the track. Turn the owner of it $ 10,000, and we will share the rest in half, what you lost.

    • subductionzone
      subductionzone

      @David Si Just put down the pipe.

    • David Si
      David Si

      @Rick Cavallaro Wait, wake Joseph Stalin, I showe who is right.

    • David Si
      David Si

      @Rick Cavallaro You say that Sarcasm is sufficient, and I say that you need to prove to the convincing case.

    • Rick Cavallaro
      Rick Cavallaro

      @David Si >> i i right u u wrong

    • David Si
      David Si

      @Rick Cavallaro No acn't agree with you you are wrong i i right . The place ofsuch "physicists" is trash I see the fact that it stinks the corpse.

  • G LS
    G LS

    Wait! Wait! Wait! Wait! You mean the earth is NOT flat?

  • William John
    William John

    Investing in crypto now is very cool especially with the current rise in the market now

    • Stone Bridge
      Stone Bridge

      I just got recommended to her on UZmilk and I invested, please how good is she

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      Huseyin Waabri

      She's really the best, I've made alot true her

    • Huseyin Waabri
      Huseyin Waabri

      12th winning thanks to Mrs Allen Lisa

    • Damian Scott
      Damian Scott

      Most people remain poor only because friends and relatives discouraged and advised them against investing and trading forex while the wise ones kept investing and growing higher financially

    • Vladimir Rostov
      Vladimir Rostov

      Allen Lisa

  • lalit pal
    lalit pal

    This is the kind of world I want where people can debate everything for the sake of learning.

  • DragonHawke Clouse
    DragonHawke Clouse

    are you freaking kidding me???? Give the ABSOLUTE LEAST amount of info to get the MAXIMUM amount of bets against you

  • Chris P
    Chris P

    Lol so you took the 10k then just get people to give you ideas for videos which you'll make far more than 10k from.

  • Hiro Lee
    Hiro Lee

    The daffy italian ontogenetically bruise because brake oceanographically concern qua a melodic rest. nasty, sloppy drill

  • spicy monitor
    spicy monitor

    Ok the most simple: the wind helps the car to go faster ; the car encreases his speed ; so just like the car has no speed ( not moving ) but the wind is moving fast than before ; which means the car will go faster than before . After that : the car goes faster than before ; so the speed will encrease slowly until it will stop encreasing .

  • fighterpilot
    fighterpilot

    Big dub

  • Some Guy
    Some Guy

    you only need the wheels to rotate faster than wind speed. the physics is rather simple tbh, just explained in a convoluted way. did not see the end of the video yet, but so far im uncomfortable with such a huge sum as a bet. on the other hand, i dont know what an american professor earns...so maybe its not so tragic. edit: the contest idea is great. you could make some community funded one, some time in the future.

  • dizefx
    dizefx

    you tf goat bro

  • Luke Trueman
    Luke Trueman

    So weeks after watching this video a odd though about somehow using the concept roller design at 13:30 to work with a mousetrap car

  • Wonderboywonderings
    Wonderboywonderings

    So, you basically did an episode of Mythbusters.

  • Jerimiah Vasquez
    Jerimiah Vasquez

    The overt vietnam definitely pass because bubble willy rule without a questionable sign. petite, flaky weapon

  • Alaor
    Alaor

    Awesome video. The only thing that I did not like was that last sentence about putting the issue to rest once and for all. In science nothing should be put to rest forever. You should encorage new ways about interpreting the data. Great work!

    • windgrins
      windgrins

      You are confusing an event with theory. A scientific theory is always questionable and potentially falsifiable by a future event that contradicts a theory. An event, once it occurs, is incontrovertible. So past events can be put to rest (assuming they actually occurred and weren't really made up). And no change in science (with maybe the exception of time travel will change an event once it occurs.

  • josef b.
    josef b.

    So a submarine could do the same? Instead of wheels there are propellers that are powered by the backward moving water, and these turn the backward pushing propeller fans at the rear.

    • J Modified
      J Modified

      You need two media that are moving relative to each other. You don't have that in a submarine.

  • Manuel
    Manuel

    Heh DDWFTTW caught quite a few physics experts off their guard. Sorry guys, this phenomenon is real. As long as there is potential energy between ground and air speed that can be harnessed, it works as long as the harnessed energy is high enough to overcome the vehicle's resistance.

    • Manuel
      Manuel

      ​@Lloyd Well I completely understand why it is unintuitive. I think the fallacy is to think of it like a system at a speed relative to air, like you would with any aerial vehicle. It wouldn't work with a sail, so why would it work with a propeller when you apply a braking force on the wheels to harness energy for powering a propeller to produce forward momentum? The reason why it actually does work is because you can harness energy relative to ground speed while you propel relative to air speed.

    • Lloyd
      Lloyd

      So what’s the issue? They look at it and see a perpetual motion claim?

  • Biggurs Bigz .
    Biggurs Bigz .

    Gone with the wind

  • Hensenstratov Diehard
    Hensenstratov Diehard

    What can I add? Such a simple dilemma caused such a noise( The average difficulty of this problem lies in junior classes of physics.

  • the wizzard
    the wizzard

    True physics people don't know as much about engineering as they like to think. What about the practical problems of having 100 of these in a confined space? What about them doing work? or are you benefiting from a unique situation with no practical applications.

    • FlyNAA
      FlyNAA

      @the wizzard sounds more like disconnected ramblings with an inability to keep track of what point you were trying to show, on your part.

    • the wizzard
      the wizzard

      @FlyNAA this is very obvious. If you show it to another they can explain it to you.

    • FlyNAA
      FlyNAA

      @the wizzard I'm not following what this has to do with your original post about "practical applications" and mass use in confined spaces, and what problem this might pose for this vehicle. It was conceived and built long before this professor or the bet, or whatever lowbrow motivations it may expose about UZmilk science videos.

    • the wizzard
      the wizzard

      ​@FlyNAA Ah, theoretical physicists tend to work with equations only and don't do experiments such as Derek has done. this is left to experimental physicists who spend their time on building experiments to prove or disprove theories. a theory is not the same as a mathematical theorem, which must be proven. anyone can throw together a theory a few ideas a few equations and pop you have a theory. engineer is a loosely defined occupation. any one can be an engineer from the person who didn't finish school tinkering in a garage, to the post grad working on the space shuttle. this is leading up to attitude and approach. for instance according to theoretical physics the bumble bee can't fly, but in practise we have all seen it fly. the engineers and practical science will tend to run with observation and leave the math to the theory guys. an electromagnetic ring will levitate 1 foot off the ground. I am not sure why, but when they built one big enough to hold a man it was still was one 1 foot of the ground and the project was scraped. as Albert Einstein said I am not interested in this effect or that effect, but in how something works. Has this effect got any more value in it than tricking an old professor out of 10 grand. this prof. lost some reputation along with his money. this is why Neil deGrasse Tyson begged off half way thru so he was not part of this prof's humiliation. now I don't know derek or the old professor, but I think it is in poor taste if this was just done for a bit of fame and fortune!

    • FlyNAA
      FlyNAA

      @the wizzard I'm a lay person.

  • Anthony Sutliff
    Anthony Sutliff

    >Nye, Tyson >scientist Pick one.

    • subductionzone
      subductionzone

      @Pablo Complains WTF? Of course he is allowed to make mistakes. I merely said that it is too bad that he made one here. Considering that he did have knowledge of this cart before hand, He actually met the maker and pilot in the past. He did later realize his error. He was merely temporarily swayed by the bad arguments of the professor. I like Bill Nye quite a lot which is why this error of his saddened me.

    • Pablo Complains
      Pablo Complains

      @subductionzone Ah ok so he is not allowed to make an error Thank you for your valuable information UZmilk Commenter

    • subductionzone
      subductionzone

      Unfortunately Nye should have done a bit better. He is an engineer and this is an engineering problem. It is not really a scientific one. Unfortunately he let himself get fooled for a while. From what I hear it did not last. He eventually realized his error.

  • TheBaihaqqi
    TheBaihaqqi

    Yeah love that you won the bet 😀👍

  • Darealchanax
    Darealchanax

    I have a way to do something similiar with magnets

    • Rick Cavallaro
      Rick Cavallaro

      That's hard to believe, but I'd love to hear about it.

  • X
    X

    Man on paper VS Man on a field!

  • spicy monitor
    spicy monitor

    It is simple: when the car accelerates it takes his acceleration from the wind so it starts from 0 to a number of miles per hour because of the wind which means it is using the wind as a power. We know that when it takes power it will be fast so when it goes fast it took another power wich is speed power (as long it goes fast as long it tooks more speed power ) because the wind helps the car to go faster just like their is no wind but the car is moving ; so the speed helps to go faster just like the wind does ( just reverse the mecanics: wind help to go faster / speed help to take more power )

    • spicy monitor
      spicy monitor

      @subductionzone only Einshtain can understand

    • subductionzone
      subductionzone

      Ummmm, no.

  • Dr. Jignesh Makwana
    Dr. Jignesh Makwana

    I think its not about speed but its about power? Vehicle output power can not exceed input wind power but vehicle speed can be higher than wind speed. Use optimised weight, windmill size, use larger gear and give additional initial boost to vehicle if required.

    • Rick Cavallaro
      Rick Cavallaro

      >> Vehicle output power can not exceed input wind power but vehicle speed can be higher than wind speed. Bingo. It's astonishing how many people will simply not accept (or even acknowledge) that no matter how many times you hit them in the head with it.

  • Genghis Khan's Chubby Cheeks
    Genghis Khan's Chubby Cheeks

    Well he's from UC Berkeley so he probably just techs gender studies.

    • Rick Cavallaro
      Rick Cavallaro

      Who's from Berkeley?

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