A Physics Prof Bet Me $10,000 I'm Wrong
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

The wager agreement: ve42.co/wager

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

My rebuttal: ve42.co/rebuttal
Huge thanks to Xyla Foxlin for building the model cart, and making the instructions so accessible to the public. Check out Xyla's video -- isnets.info/main/iYbLxZp92mSjptE/v-deo.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

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.

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


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

  • Steve

    Derek knew before he made the bet that he was right. The evidence was already there. He just neglected to tell the scientist and made the bet anyway.

  • 32a34a

    This is why I sit in the corner with an empty look in my eyes with drool coming out of my mouth. I just cannot grasp this math no matter how hard I try then again I really can't try that hard because my brain went dude please what are you doing just grab some cake and go sit in the corner and listen to some Pink Floyd.

  • ishtar dante
    ishtar dante

    GG from France^^

  • Walter Wu
    Walter Wu

    Still don’t think you’ve done a good job explaining this. You didn’t mention gear ratios at all, until the very end, and only in passing. The two-by-four example is helpful, but not totally accurate,

  • Dan Eady
    Dan Eady

    Well done. You explained it well in the end.

  • Mister Myself
    Mister Myself

    "Aginst the Laws of Physics". A Law is supposed to be able to be 100% duplicated, 100% of the time. So I guess the Laws are wrong? It wouldnt ve the first time but it just shows its all a guess really.

  • Nismosaki

    That professor is just a fool.

  • matt sez
    matt sez

    correct me if im wrong.........but if i followed this right, you could push the cart up to 10 mph with a car, in zero mph winds, no wind what so ever......and the wind cart would still accelerate , because with zero wind, it would be the same as once you matched the wind speed in your test. 10 mph in 10 mph wind = zero force from the wind. the tread mill test is using outside power to move the drive surface, so i dont think its a 100% re enactment , it basically simulates going down hill ( gravity then being the out side power )

    • infinitelyExplosive

      no. If there's no wind and you're going at 10mph, the air moves 10mph backwards relative to the cart. If there's a 10mph wind and you're going at 10mph, there's no air movement relative to the cart. The cart only works in the latter case. It needs the air to move relative to the ground.

  • Savage Comments Channel
    Savage Comments Channel

    Veritasium is not just a ISnetsr, he has a PHD in Physics. This means he does research to put things down.

  • qopoy dnon
    qopoy dnon

    14:00 Watching the wheel turn opposite to what is intuitive hurt my brain.

  • David

    Why not just build cars with large back wheels and small front wheels? That way, the cars are always going downhill and burn less fuel. How much do I win?

  • ⠀

    well, finally the truth. Professor Kusenko you are a man of honor. Veritasium you are out of the box. and Xyla Foxlin you are so dang gorgeous just really really realllyyyyy gorgeous

  • John Miuranda
    John Miuranda

    Stupid bet. Sailboats have proven it can be done, much less a land yacht.

    • David

      @John Miuranda Lift allows a 747 to rise, but its jet engines provide its forward thrust. How does the lift from a boat's sail make it go faster than the wind? (I understand that the lift reduces its resistance to the water.)

    • John Miuranda
      John Miuranda

      @David you obviously read the report and believed the reporter word for word. Its not about tacking, its the lift generated by an air foil. In the case of a boat its the sail, and in this case, its the rotary wing thats the propeller that is then harnessed by the land yacht to further propel it. At the end of the day, its simply lift. Same energy that allows a 747 to fly.

    • David

      Sailboats use an entirely different method for achieving this feat. The car travels in a straight line, it doesn't tack.

  • Leonardo Twinkle
    Leonardo Twinkle

    My Thoughts - You say the Propeller is connected to the wheels by chain meaning, At first the Wind will start to move the wheels until it gets to (How ever fast the wind is going) after that the propeller will be running on wheel power and just becomes Centrifugal Force. The Propeller picks up speed, wheels will then pick up speed and then it just keeps looping but it will eventually Stop speeding up

    • qopoy dnon
      qopoy dnon

      moves forward and backward like in an oscillation).

  • Ward Smith
    Ward Smith

    I get how it works once it starts rolling, but is the wind pushing that propeller to begin the motion? If so, how?

    • FlyNAA

      The initial push is just simple dumb drag, with no prop effects - as if it was a giant cube on wheels. From there, the wheels starts being driven by the ground, and in turn driving the prop, which starts to act as a prop.

  • David Sault
    David Sault

    The Blackbird is acting as a capacitor charging up. It stores the “charge” in the form of kinetic energy or momentum, but the wind, acting as a steady charging source, is continuing to add energy to the system. Think of an asteroid falling down a gravity well and constantly accelerating. The Blackbird would continue to accelerate as wind energy is added until the drag opposing the stored energy is equal to that energy and any further increase in energy is balanced by the increasing drag at that point (terminal velocity). The propeller is the mechanism that stores the energy. Think of blackbird sitting static. Then the wind blows. Does the blackbird start instantaneously and reach its maximum speed instantaneously? It must accumulate enough energy to overcome inertia first and then accelerates as that energy continues to grow past that minimum required energy.

  • Robert Attkisson
    Robert Attkisson

    Lost me with the addition of bill nye the toxic guy.

    • David

      What do you have against Bill Nye? I mean he's no Mr. Wizard, but still.

  • David

    Whose side were Neil and Bill on before the truth was revealed?

  • matt the mechanic
    matt the mechanic

    Tacking. Is it well known that a sail boat can move faster then the wind by tacking. Is it possible that the props are actually acting as sails that are "tacking" very fast?

  • Ryan Woodhead
    Ryan Woodhead

    It’s entirely possible! I can understand it and I’m a sophomore in high school.

  • Anton Taylor
    Anton Taylor

    Would adding hub motors and solar panels to blackbird make a more practical vehicle? A hybrid solar/wind vehicle? I'm sure you could add solar panels in a way that would have a minimal impact on aerodynamics, and could result in an extremely interesting vehicle that may even have real world practical applications. Maybe... :D

  • gmonkman

    Good channel, but downvote for the clickbaity title. While you are at it, challenge ElectroBOOM on the Mould Effect - clicks and coops to be farmed!

  • Biikerr Ypvs
    Biikerr Ypvs

    At first, it's obvious!) for far more reasons, which were not captured or I did not hear them well😅(my english is not as I want to be🙆‍♂️). There were lot of mistakes You were done at this chalange. I mean, the vehicle. 1. Wibrations are consuming PLENTY OF POWER, causes the Energy losses. But it is unfortunately moving propeller for left, right, up and down... Some kind of spiral movement, that produces positive"force from adding an angular force so it is quite as yachting. 2. You have a lot of power loss from gearbox. It would better, to have a real transmission/axle with, friction in minimum. 3. Propeller eorodynamics... And now... It has sone problems that YOU WERE NOT bring up. 1. Propeller aerodynamic profile causes extra force inline in course. 2. Every part that spin, has some torque adding some force inline in course. So why I said ALL OF THIS is obvious? OF COURSE it is well known, that any object without losses/friction has given even small force, it would be accelerating for infinity. You are talking about AIR VELOCITY, but You are jot considering some factors like AIR FORCE. For some reason we can assume that this force can be enormous(like air masses from bilions of cubic meters) even when velocity is small. Like an engine with one horsepower and tousend Nm torque. It is not said, that, vehicle with that engine will be slow. It depands of gearbox. So my conclussion is, that air mass force with very narrow propeller aerodynamics can make enormous torque when propeller is joined/teamed with gearbox even like Yours(very simple). It is possible, to accelerate this kind of vehicle 10times faster then AIR SPEED, when this air force can prodce enough wheel speed. There were somy tricky aspects that affects this force like air density(sea level, temperature, humidity) regardless to air speed. There where another construction that could do that the same, as Yours, but I will not tell about that here. In youtube comment....... And personalny, that profesor is realy shallow~minded. A very... I realy dont undesrtand bove of You guys😅😄🙆‍♂️🤷‍♂️. It is very simple from "a to z" to do that thing. When torque at the wheels are strong enough to acceleratethe vehicle overcoming the losses from air (cx) and rollingResistance(i dont know if this world is good to describe what i mean😅) IT ALLWAYS BE ACCELERATING, FOR SPEED THAT CREATE SO NEGATIVE FORCE(AIR RESISTANCE) that align with possitive and there will be constance as ling as possitive force is given. Peter from Poland.

    • Biikerr Ypvs
      Biikerr Ypvs

      However these models is a crap. Two reasons. No air resistance, and massive kinetic Energy on running trak. In combination of: for example very high gear ratio, and very narrow propeller aerodynamic profile we can get so much thrust that when we were noy holding this kind of model it will accelerate like a dragster from that walking machine😄😅😂🤣

  • Jaime Henderskin
    Jaime Henderskin

    So I'd like to see a bet about how "Green" that wind turbines are and solar panels and ethenol blended fuels and having DEF and DP filters are on diesel engines verses just making engines more fuel efficient (without ethanol additives for gasoline engines) and without devices that restrict efficiency for direct injection diesel engines or require to burn more fuel to clean out DPF devices, and to find out what effect that oxcides of nitrogen has on the environment over all.

  • Mirror16

    The biggest outstanding question to me is this: how on earth did that man become a Physics Professor at UCLA?

    • David

      He studied, a lot. Everybody makes mistakes, few admit it.

  • Davian Olivo
    Davian Olivo

    5 times a sec. And the dark grey one 30 times. Love the vid btw

  • Jack Mehoff
    Jack Mehoff

    There is a real easy way to prove this with something that already exists, just look up helicopter tail rotor drift, what it is but more importantly what causes it 😉

  • dadt

    Derek, what happens if everything is the same, except the fan is turned 180 degrees ("facing" the back)? Can one of the following two scenarios be possible? As the wind picks up the car moves forward, but now the fan is generating a backward thrust, so there is deceleration. The car may slow down, it will then accelerate forward again like in the beginning (this cycle repeats). Or the car will move backward after initially moving forward. As the car is moving backward, the wheels will rotate the fan in the opposite direction as before, so now generating a forward thrust that decelerates the backward motion of the car until the car will move forward again (and this cycle repeats itself, so the car just moves forward and backward like in an oscillation).

  • MrArtVandelay

    So impressed with these guys. Neil DGT is a god to me, as is Nye. Amazing guys who I will listen to anytime I hear them talking. The UCLA Prof is awesome too.

  • Mars Luna
    Mars Luna

    What a wonderful video. Thank you!

  • 510jesus

    it's just plain WRONG. Give that man back his money. Remove the chain and see what happens. The vehicle can keep the wheels and propeller blades but get rid-off the motor (chain linked to wheels and propeller) otherwise this is just not what it is advertised. I call a double technical with the inclusion of the motor

    • FlyNAA

      Remove a part that makes the thing work, then the thing stops working, therefore it doesn't work QED

    • infinitelyExplosive

      How does the presence of a chain make it _not_ wind powered?

  • David

    I suspect a fair amount of research is tainted because investigators are biased by what they intuitively feel the answer should be. This unconsciously blinds them to what the facts indicate.

  • jonathan leslie
    jonathan leslie

    I don't understand how the gear ratio's don't play a major role in getting this to work. If your wind source is sufficient, by adjusting your gear ratio to overcome the resistance to movement, then you can cut the differential between the force to maximize speed. the same way that when pedaling your bike downhill, you can switch to a higher gear to convert your force into speed rather than torque power.

  • Uga Uga Uga
    Uga Uga Uga

    Very educational. Congrats on the victory and the science. I'm always happy to see narrow-minded experts get proven wrong.

  • sketch6995

    Hunni what happened to the kids college money? You better tell her a story about alcohol and hookers......cuz she ain't gonna buy this one.

  • bruzote

    As for holding the car in place, isn't that like pushing the car over a non-moving treadmill? If you're pushing, then that is cheating.

    • FlyNAA

      After they bring it up to speed, it works without being pushed. It's only to bring it up to speed within the limited footprint of the treadmill. They full size one came up to speed it itself from a standstill on the desert floor.

  • bruzote

    I have not watched the video yet as of this comment. It would seem that despite the fact the car is using a rotating blade, the problem has been misconstrued as a flat-boarded windmill pushed by wind. Without deeply thinking about the problem, it would seem that the TRUE wind blowing across the airfoil will determine the speed of the car. Since the airfoil's rotational component is giving the blade a relative motion that is perpendicular to the "downwind", then the two wind speeds should combine to create a true wind speed. This is something that sailors know about when tacking. However, having the windmill go faster than the wind is different than having the car go faster than the DOWNwind. Sailors exceed windspeed going ACROSS the wind, not DOWNwind. Hmm, the way I see it, you need speed variations, just like the professor is saying. If you exceed downwind speed, the propeller must bite INTO the wind. WAIT A SECOND! You can blow wind AGAINST this kind of car (headwind) and the car can travel INTO the wind. Now, if you just call that a NEGATIVE-SPEED downwind, then the car's velocity WILL exceed the magnitude of the velocity of the air. So, IF this is a trick question of defining "exceed", then of course this can be done. If this is not a trick related to negative windspeed, I just don't see the car exceeding the downwind speed in a steady-state solution. That's my final answer. I hope I am right!

    • John Borton
      John Borton

      // "If this is not a trick related to negative windspeed, I just don't see the car exceeding the downwind speed in a steady-state solution."// Blackbird. Steady state. 3x windspeed.

  • metacamman121

    If truth ruled instead of politics.

  • Trevor Billows
    Trevor Billows

    "What I love about science is that disagreements are not problems, they are opportunities for everyone to learn something" --- what about when the disagreement is about science's truth itself... 🤦‍♂️

  • rRobert Smith
    rRobert Smith

    Not to come to your defense, BUT a sailboat on a tack moves much faster than the wind (since it is harvesting much more energy).

  • S C
    S C

    $10,000 is nothing compared to what he made on this video talking about winning $10,000

  • Nimrod Quimbus
    Nimrod Quimbus

    The professor doesn't even understand the definition of Velocity.........And we wonder why kids dont know the difference between male and female......

  • Vriska Serket
    Vriska Serket

    Bill Nye has no business in anything science. He has no qualifications. He's a performer and an ass to his fans.

  • batchelerjr

    Your witnesses are shills? OMG Your going to game a UCLA Prof. some how. Shill grandson then. They are giving him a reacharound and the experiment has not even been shown. So you like this gamer

  • phatpat63

    Why am I not surprised that a UCLA physics professor is constantly using conspiracy theory logic.

  • masseur1950

    Right now the America's Cup boats are DOUBLING the speed of wind!!!!!

    • 191246mann1

      yes the boat can go faster but they have to go across the wind but not in the direction of the wind when they go with the wing they put the spinnaker up and that will never go faster than the wind ..who would bet 10000 when all he had to do was look on the internet to see it was done 10 years ago ,ask them that,you only have to put faster than wind on .

  • Devashish Sood
    Devashish Sood

    At 11:07 how is the propellor covering a different distance than the wheel?

    • eyytee

      The propeller is moving less distance relative to the air, than the wheels are moving relative to the ground. See the AAPT physics olympiad solution linked in the description for more details on how the relative motion between the interacting objects determines the power harvested / expended.

    • eyytee

      @Gregory Kilcup To merely show that the concept doesn't violate energy conservation (the physics part), the simple idealized formula Derek shows is sufficient. You only need the complex formulas Drela uses to predict the actual performance (the engineering part).

    • Devashish Sood
      Devashish Sood

      I’m not sure whether what I did was right either, but my friend and I found it easier to envision what was happening that way.

    • Devashish Sood
      Devashish Sood

      @Gregory Kilcup Thanks. The way I tried working around that is think of the wind being pushed out instead of the propellor when that graphic was shown, and it makes somewhat more sense. But what you’re saying is super helpful. Thanks!

    • Gregory Kilcup
      Gregory Kilcup

      It is good that you find that part confusing; what Derek says just there is not correct. When talking about "the wheels moving over the ground" he should have said that since the ground is stationary it provides NO power (when analyzing in the ground frame of reference). He does better when he says he want to talk about the cart's frame of reference, where the moving ground pushes on the bottom of the rotating wheel to produce power Fground*v. But then he writes the wrong formula for the power going to the wind (that's why he has to talk to Drela for a minute), and incorrectly equates the two powers, ignoring not only drag but the fact that the cart is accelerating. Basically, I recommend you ignore the two minutes after 11:07 and start up again with the board and trolley demo.

  • Jeremy Pilot
    Jeremy Pilot

    My guess is the weight from the blades have a conservation of energy so once they are set into motion they act like a perpetual motion device and continue to make power. Since there is always some wind the loss of motion is countered by the reintroduction of energy from the wind. So while the wind powers the blade it doesn't cause the force forward if that makes sense.

  • Meat Sweats
    Meat Sweats

    Am I the only 1 that doesn't take a person's money on a bet but will pay up if I lose. I certainly don't bet very often at all. Not for that reason. I will bet over something fun and it may be $20 tops. I just feel guilty taking other people's money. I wish I didn't, lol.

  • Yamac Taraktas
    Yamac Taraktas

    you can not scale that experiment with the treadmill. those are 2 very different experiments. on treadmill is when youre an motionles object givin pover from axel to wings to create high positive pressure to get the car to move on the real car you give wind to the propellers to transfer that pover to wheels to get the wheels to move

    • FlyNAA

      @Yamac Taraktas the high pressure behind (and low pressure in front) is there in the full size cart on the desert floor, same as it is on the small cart on the treadmill, same as it is on any propeller-powered vehicle.

    • Yamac Taraktas
      Yamac Taraktas

      Just a question. Would the results be same If that small model put in a wind tunnel? That would be the right test method. Or just a blow dryer on the car. Testing method is not correct. Theres an uncalculated high pressure behind that will allow the treadmill car to go forward the real car wont have.

    • jonathanjomen

      @Yamac Taraktas ... but the propeller (not a fan) *is* powered by the wheels right from the start and it *is* moving the car the car is exploiting/converting the energy of the wind by taking advantage of the speed difference between the two media there is no problem - except with your understanding of it ;) _the purpose of this experiment is to prove the propeller can move the car,_ no - it's not the purpose is to demonstrate what happens at the moment in time when the car is at wind speed - whether there is consistent forward thrust ...

    • Yamac Taraktas
      Yamac Taraktas

      @FlyNAA thats the problem the purpose of this experiment is to prove the propeller can move the car, not to have a fan powered by wheels

    • FlyNAA

      This is not true, in both vehicles the wheels power the prop. Never the other way around.

  • el crazee
    el crazee

    maybe smoke can explain clearly.

  • Drum Ape
    Drum Ape

    My guess is it has to do with an area of low pressure being created in front of the propeller as a result of the counter spin of the propeller head. I honestly thought the professor was right.

  • SerpentInside

    RE: Neuro, yes because scientists are bathing in money. LOL.

  • SorryN

    @10:34 i think it is like swimming in the water..even if the current is high enough you can still be faster than the current if you swim in the same direction and use your hands to push water backwards

  • Timmy Ha
    Timmy Ha

    :pinched_fingers: :pinched_fingers:

  • 191246mann1

    lets keep it simple for me to understand at 10 mph are the wheels driving prop giving it more power that it needs to keep going or is the prop producing enough power to push the car along and go even faster,

    • John Borton
      John Borton

      All the power is ultimately supplied by the wind, but the wheels certainly do provide the force to turn the propeller at 10mph and all other speeds.

  • Nabrid Obcsje
    Nabrid Obcsje

    01:25 You want to know if you are wrong. The purpose of science is to demonstrate and expose error, science is not a method of proving truth. You are a scientist.

  • Utkarsh Kumar Gupta
    Utkarsh Kumar Gupta

    Is it you Sheldon ??

  • Bernard Chu
    Bernard Chu

    Wow Congratulations sir

  • eioshen boboi
    eioshen boboi

    The high jesuit priests of science who would never lie or decieve.

  • ur maddy
    ur maddy

    Can anyone provide me with mathematical model of the wheel system provided as a mechanical analogue of the experiment?

  • clash ott
    clash ott

    .Assuming Wind speed is fixed

  • Tajr

    you are both really cool people. what a win for science communication

  • Driveway STAR
    Driveway STAR

    Attach some variable size wheel and increase the wheel size with ground speed. ie: constant variable transmission. Why do this? I dont know itd be cool

    • eioshen boboi
      eioshen boboi


  • Theophilus Chambers
    Theophilus Chambers

    Heads up, this video made more then 10k ....

  • Milamasylum

    Can you imagine thinking you're smart but then a ISnetsr proves you're not...

  • shadyonej

    Amazing 😳

  • silentbob1236

    The reason a sail boat can move faster than the wind is because the boat itself is moving at a diagonal to the wind. If you are moving the same speed and direction as the wind, there would be no wind relative to the vehicle..

    • subductionzone

      The propeller blades are moving at a diagonal. If you "open up" their path are they rotate around you can see that.

  • Flat Sabbath
    Flat Sabbath


  • mallu troll Videos
    mallu troll Videos

    Can I ask you a question 😁 sorry if my english is bad. If we combine oxygen and hidrogen we get water.when we do this the energy is also released.but one thing is it explosion or implosion 🙄

    • mallu troll Videos
      mallu troll Videos

      My second dout. We can make engine that run on water mke H& O then combine together.. everyone knows it . Ok when we burning the fuel we get water on exhost pipe plus some unburning fuel too so can we use that water to feed again to the h2o generator and the gas to feed again to increase the efficiency 🙄.the water will recycle again and again 😁 pls answer me

    • mallu troll Videos
      mallu troll Videos

      Answer pls then I can ask another doubt 😌

    • mallu troll Videos
      mallu troll Videos

      I think it's implosion because the gas is big and we combine together we get liquid 🤔

  • LeakingAmps

    That board really broke my brain. I'd already concluded that must happen following the arguments put forth, but seeing it happen made my brain a bit unhappy

    • R G
      R G

      It's all about frames of reference. Don't think about it like the wheel going the wrong way. Think about the big wheel using the small wheels to stay "still" on the board and using that energy to roll down the board (watch the video upside down!)

  • trolololmfao

    Anyone got that baddie xyla @?

  • e- kaan
    e- kaan

    That means you can not calculate the power of wind only with its speed. Even the propeller gets effective power from the wind.

  • Shawnonsens3

    long story shorty v got 10k lol

  • Dan Ran
    Dan Ran

    I’d hate to be friends with this dude, let alone be married to him... Lordy hell

  • thespicehoarder

    I legit thought you were wrong right until the wooden board...

    • subductionzone

      There are quite a few different arguments that convince people. I used to argue against this years ago. It was when Rick made his first crude treadmill cart that I realized that he was right and that I was wrong.

  • reynard ralph manos
    reynard ralph manos


  • Weeb San
    Weeb San

    10000$ EZ 5head

  • Adam Foley
    Adam Foley

    Glad Bill Nye the gender is a spectrum guy could officiate / what a joke.

    • Max

      @Adam Foley your sex and your gender are two different things. you can not change your sex but gender is a made up term that we often associate with sex

    • Adam Foley
      Adam Foley

      @Max imagine disregarding established biological science and promulgating lies to children that gender is a spectrum using your platform as a pseudoscientist entertainer. You’re entitled to your opinion but I disagree with it.

    • Max

      imagine disregarding one of the most respected scientists in the world just because he disagrees with you 💀

  • adamgh0

    13:54 the moment he wrote that check...

  • Fredo A
    Fredo A

    Is anyone coming back to this video and realizing the email part where Bill Nye switches sides is removed? Me and my friends did not make this up. Veritasium removed that part from the video recently for sure.

    • subductionzone

      I too seem to remember him saying something negative about the cart. Though when I listened longer I may have conflated that with the fiend of Muller's that thought that he had lost.

    • John Borton
      John Borton


    • MikeInABQ

      One can imagine why a first reaction would be to think it would violate a law to reach the speed of a steady state wind blowing in the same direction, when thinking of it as a kind of spinnaker effect. If the source of energy were a PV panel, it would be easier to see why the device might provide enough energy to go faster than the tailwind because it could move with no wind at all, but since the prop also relies on the wind to move the vehicle from a stop, it's easy to miss the part about the gear ratio making it so that the prop is eventually propelling the vehicle instead of just collecting energy. But, I might have my thinking crossed up here, so I hope somebody can explain if I've gone off the rails.

  • Ahmad Farzam Karimi
    Ahmad Farzam Karimi

    Did anyone notice the scene from when Bill Nye sends the email agreeing with the professor and now that scene is just gone?

    • John Borton
      John Borton


  • MikeInABQ

    Of course it can go faster. If the prop were like a spinnaker on a sailboat, then it could not drive the car faster than the wind in the direction of the wind. But why would we think no prop on a vehicle could collect more energy than needed to move the vehicle faster than the wind?

    • MikeInABQ

      @Gregory Kilcup Yes, as the only source of energy at the beginning, it's easy to miss how the device isn't limited to that.

    • Gregory Kilcup
      Gregory Kilcup

      Because one might think that the job of the prop is to collect energy, and that when the relative wind is zero, there is no more energy to collect. That's the trap which ensnares many.

  • Syed Osama Safdar Bukhari
    Syed Osama Safdar Bukhari

    The most convincing analogy was that of the torque.

  • Mat Bess
    Mat Bess

    @veritasium Can please explain why the propeller kept spinning faster and faster while the wheels were barely turning in the first video (12:20) ?... this still bothers me.

  • Tim Beyer
    Tim Beyer

    Great video! Time to do something on the EmDrive?

  • PerdixDesignLtd

    I'm lucky I get mental challenges every day. I just really appreciate the search for truths. Science doesn't have all the answers. But it tries to ask all the right questions!

  • robby garza
    robby garza

    The squealing danger unintentionally tickle because deal connolly x-ray aside a pink blinker. proud, witty dead

  • Michael Weintraub
    Michael Weintraub

    The high jesuit priests of science who would never lie or decieve.

  • Kartikeya Kapparwan
    Kartikeya Kapparwan

    Derek, I think you should set up an experiment to see whether a ship (some type of submarine) can do the same upstream.

  • Anzuis

    Your next contestants need to be Mehdi vs Mould! I need an answer!

  • Roy Faust
    Roy Faust

    Bill Nye? Really? A stand up comedian? He has no credibility in the science world outside of the TV entertainment world.

  • André Ribeiro
    André Ribeiro

    Can't get much better than this... great work from both of them.

  • Max Stewart
    Max Stewart

    Okay two questions: The propeller will generate (either direction that it goes) some form of lift, unless this is a lot heavier machine than it seems, thus lifting the vehicle ever so slightly off the ground (rear wheels). And the drag coefficient of the wheels to the surface, it's a not a hard surface so you will have slippage versus the softer ground, so the wheels should and actually it seems they do not spin at a constant speed in your frame rate. If you run this on a hard surface like a drag strip and get the same result I would give it to you. At this point still with the professor.

    • eyytee

      If the wheels were slipping the performance of the cart would be worse. it requires good traction to work well.

  • jmbootz

    Betting money? That's unimaginative. Penthouse subs? That's science.

  • cavemandan

    so obvious you can go faster than the wind speed... physics teachers are not mechanical engineers...obviously...... i used to argue with physic teachers 40 years ago.... one idiot thought the laws of physics were constant throughout time..... another thought the speed of light was constant.... i'm glad i did not waste money going to UCLA...seems they will hire anybody

  • Aleksejs Nikolajenko
    Aleksejs Nikolajenko

    :D Still looks as some magic.

  • Rei Caixa
    Rei Caixa

    I should be writting right now, stop posting these interesting videos, damn it lol

  • jason cockington
    jason cockington

    Great Vid. You had me hooked right to the end. Do you take requests? I've always wanted to know is it possible to create an infinite water wheel if you couple it to a water screw? Can gravity provide enough potential energy to overcome the energy loss in rotating the screw and pumping the water back to the top of the water wheel?

    • Gregory Kilcup
      Gregory Kilcup

      No, but if you put your water wheel in a flowing stream you can take energy from the stream.

2,3 m.