Windmills Are NOT Like Dams 

Good april fool's day video considering windmills are giant fans, and they are responsible for all the wind.

"uploading a serious video on april fool's is a fool's errand" - Tom Scott

The best April Fools joke is one that makes you think you're being fooled when in fact you aren't.

I have actually learned it in college last year. You used two minutes to explain two whole lecture's knowledge. You are a legend.

For the whole time I kept thinking 'you are hiding the april fool's part way to well, people are going to actually believe it if the rest of the video is making too much sense'

Fun fact: All minutephysics videos are so awesome, it only feels like a single minute when you watch. It’s the most enjoyable kind of time dilation.

Actually had to study this in one of my majors while studying Mechanical Engineering back in college and this video summarizes and explains this stuff really well!

I'm an average guy with no real academic degree or whatever...but... my thirst for understanding physics grows with every video i see from this amazing channel.. Thank you sir.

Thank you for keeping me from not learning.

This is something I had to learn during my Aerospace studies regarding propellers. It's the same, but the other way around.

He is the one of those who uploads video which I can't see in 2x.

Been following your channel since my high school physics teacher introduced the class to your videos over 10 years ago… every week we got to spend the first 2 minutes of class enjoying your videos… glad you’re still making great content

glad to see you posting again great video

I appreciate that nod to the complexity and the book pages at the end.

Wind...Mill? Behold, sciences latest triumph over wind power - the Windlathe!

This brings back memories about how I found out about this figure. When I was elementary school (15+ yrs back) I really liked to make windmills from wood wings (like 1,5x5 cm wide wood-piece and with knife/polishing making somewhat triangle from that with smooth "catching" edge and rounded back for light-weight and more "efficiency"). Three best examples had 3 wings (~0,8 m long each), 3 wings (1,1 m each) and my best - 5 wing (1,2 m each) design that worked at lower speeds than 3-wing (it was located low to ground with uneven terrain/trees around so only 1 lower wing (with 120 degrees between) had trouble to keep speed up and it lead to vibrations. 2 lower wings (with 72 degrees between) solved issue and it was smooth and worked as expected. And it was this time when got to figures how wind speed impacts power (not sure how precise but from that time used m/s^3 = W/m2 formula whenever wanted to know how much power windmill actually can extract - and that "nominal" power was based on ~9 m/s windspeed). And how efficient it can get (figure in video) etc.

So a legit video. Apparently cut content - nice! Thank you.

Brilliant! I was gonna make a video about this for my Power Systems students, but now I just have to give them the link to this video!

Betz's law! Finally I know where that 'magic number' comes. It's quite familiar for mechanical engineering students who studying fluid dynamics

Great content as always! Though the "solution" in the title actually had me hoping that we were able to surpass the 59% limit! Looking forward to your future videos.

Awesome explanation on Nebula! More please, my fellow Physicist!

Amazing video!

The problem with windmills is that when the wind blows in the opposite direction the blades turn the other way and suck electricity out of the grid.

might seem complicated at the first time to me, but it's well explained when replayed. I didn't know I can catch up Betz's law in 6 minute. Thank you

A corridor crew video from 2016 brought me to this channel. Thanks Wren.

This couldn't have come at a better time. I'm doing my final year dissertation right now and a section of it is about windmills and energy extraction. This helped me a lot with understanding it better.

I was hoping for an April Fool's joke

This is a good explanation of the math in Betz's paper! Do you think you could do a video on Betz's paper on multiple rotors?

I learned more from this channel than all my online classes combined.

thought it was gonna an Aprils fools video and was waiting the entire video for the nonsense to start

Wow sir, how did you make this video, without you actually showing yourself onscreen, in the sense your hand!?! Beautiful !

In the first clip of the outflow pipe moving up and down the side of the reservoir, you say that you can lower the water without slowing the flow, but wouldn't lowering it increase the pressure and make it flow out faster?

Please go more in-depth on the energy differences of drag based windmills vs lift based windmills

i'm kinda disappointed that i learned something on april 1st

Hey the videos you make are dense packets of information and are awesome , but here you have just given the explanation for Betz limit right?then how is it a solution to windmill paradox? Or is it just a way of putting content related to April 1?

I'm already a curiosity stream and nebula subscriber, it would be really cool if you gave us a direct link to this video on those platforms, so I can pop over there and see that video without having to search and find it

Great video, thank you. Could you, maybe next time, also share references to the papers/books you are using in the video? Chreers

I was partly wondering if this would be about how much grains they could mill, and partly how much they should be allowed to tumble around over the countryside (not on the post, much like a big loose wheel).

So in the city could a build have windmill floors basically windowless floors funneling air through, would that also help in reducing sway allowing some air to flow through instead of just crashing into.

Great woooork 🥳🥳🥳 Thank you 💜💜💜

- Making video to explain interesting PrObLeM then do it with the speed of light is a pRoBlEm itself . - Compressing information to produce a short video that sAvE TiMe made me pause/back a lot in order to catch up , which wAsTe my time any way . - It is not about given an information , it is about how to present it . ~ keep up the good work , thank you

Didn't know I needed to know this, but I'm a fan.

Ah some minutephysics😃

It'd be very nice and handy if the Nebula video was linked in the description.

Very short, very interesting! I feel like some people may have gotten lost cause of how fast it was, but I was fine (granted I'm a physics and science ed major...)!

I wish the winds around the region I live could be reduced a lot.. here we even gave a local name to the wind that hits this region of Spain.. It is called Cierzo and it is quite strong, a lot of windmills could have a lot of benefit from it and ease on the wind that hits the city.. haha that would be nice..

Do windmills have adaptive systems to deal with changing wind speeds?

What are those scientific papers you cite/show ? Why doesnt the description mention and link those, such that we may have a chance to try to make those computations by ourselves? Im sure the math involved is intricate

Can you link the nebula version in the description? Very annoying to have to navigate to it. Also annoying to find out there is an extended version of the video on Nebula at the end after I've just finished watching this version.

All good points.

Can you make an updated version of your time travel video with endgame, dark and tenet time travel system?

Please put a link to the extended Nebula version in your video's descriptions. It's pretty annoying to have to navigate to it (Nebula is slow...)

@minutephysics I really want you to explain CT clamps on AC circuits. How can an RMS value give a direction on the current. Please investigate.

Could you please make a video of how does a gear work or how does the engine work

So i got an important question i need answered. I read in a few pages that apparently either exists or will exist a type of computer that will run instead of on 2 stages, on and off, with 3 stages, on, off and in between, called quantum computer. If such thing is the case, could we use the principal of teleportation to transfer internet globally at the speed of light without cables? Could we do it with the internet as it is? I hope this makes sense

Isn't this called the Betz Limit ? What about vertical axis wind turbine ? Does this limit apply ?

There was a point where I think you could elaborate more at: when saying that lower speed means the windmill extracts energy from "less" wind, I had to think pretty hard to realise you meant "wind of constant density"...

2 uploads in one week? From both Veritasium and Minute physics??

minutephysics: Posts a new video. Almost Everyone: Go straight to the comments section!

Cool, i miss this

0:54 , 1:36 , 1:40 There's an error : it's not "wind volume" but "wind section" or "wind area" or "closed surface" in mathematics. (in fact, saying "volume" is absolutly wrong, volume per second is actually constant, by conservation of mass) Plus, you showed why speed at the mill was 3/4 of in speed but not why it means 3/4 of wind in SECTION(!!!), on a slide that titles "conservation of mass" but doesn't use it. Explanation : flux formulas : flux (unit/s) = j (unit/m².s) . Surface (m²) j (unit/m².s) = density (unit/m³) . velocity (m/s) ( "j" is "flux density" but I wanted to keep one word per variable) In the case of a windmill, air compression is negligible, so there is no noticable variation in density. We'll consider density as a constant D. Thus, flux = D . velocity . surface For a given flux F, in other words when you conserve mass (or electric charge or "unit" of any quantity), an increase in velocity means a proportionnal decrease of surface. Proof : F = D . v(a) . S(a) = D . v(b) . S(b) or more interestingly v(a) . S(a) = v(b) . S(b) or in an other form v(a) / v(b) = S(b) / S(a) if v(mill) = 3/4 . v(in) then, v(in) . S(in) = 3/4 . v(in) . S(mill) => divide both equation members by v(in) => S(in) = 3/4 S(mill) ◻ PS : at 1:05 , 1:18 , "as much wind to pass" is given by wind section S(in), not wind velocity v(mill). Yes, it's the same proportion, but mixing surfaces and velocities has no sense... It's like saying a bottle of water has a mass of 1L. Yes, 1L of water = 1kg. But 1L is not a mass!!! Don't mix speed and cross section even if you fall on good numbers.

I wish my physics lesson was this short and understandable

How many birds and bats can a windmill mill?

as the saying goes How much wind can a windmill mill if a windmill could mill wind? It would mill as much as it could if a windmill could mill wind or did it use woodchucks?

I want to thank you for not uploading an April fools video

We need a video on the muon g-2 results

I had never thought about wind volume… that's wild

a video on MUON G-2 experiment please🙏😀

I can't make a joke yet, the video hasn't even started

I can't believe this video is not just a bunch of hot air.

The most you can mill from wind is 100%. With a type of mill called sail.

Why does this feel familiar. It says it was uploaded yesterday, but either I've seen this video before, and recently, or someone else made a very similar video very recently.

Exact name for this is : Betz's law. From Albert Betz.

I actually knew it was about 60% because a friend of mine did a science fair project on it back in highschool (he mounted different windmill designs on top of a truck, it was pretty cool). But actually this number doesn't matter that much because windfarm windmills actually extract a lot less energy than this, partly because this works for single windmills but doesn't account for several windmills lined up behind each other.

What is volume of the wind?

where is the nebula version link man

This makes me really wonder, if humanity completely switches to wind power, would that actually influence the climate through slowing down winds???

Can you make a video on super capacitors

Big fan from india

how about different windmill designs ?

Huh. I had no idea. I'll have to see your other video.

Love From India🇮🇳❤️

“WINDMILLS DO NOT WORK TGAT WAY! GOODNIGHT!! “

Wow, someone gave a thumbs down before it's even started!

I don't really understand the 3/4 wind volume thing, can someone help me a bit?

I love to study physics but I generally gets stuck with lack of formula on the needed time and sometimes I get frustrated by the calculations. Can you help me❤️❤️

That kind of flew over my head.

Forgive me if this is a dumb question, but why would we care about the efficiency of the energy extraction - i.e. isn't more energy farmed always better? Why do we care about per unit wind when there's an abundance of it, it's not like there's a problem with taking as much energy out of the wind as possible yeah?

0:09 thats not entirely correct... The flow pressure is proportional to the outlet's hight, and if im not mistaken - therefor the velocity. But i get the point

I liked the first title of "how much wind should a windmill mill"

What's up with your fascination with wind mills??

What i heard was: How much does windmill mill the wind when windmill mills the windmill and windmill slows down.

I figured it out after he said there is more in depth parts to this

Dam windmills... dam. I can't think of anything to add to this dam pun.

I always wonder if slowing the wind any effect on nature? Doesn't nature need winds in order to survive?

Windmill Energy Conservation, 56.25% HD TV 16:9 aspect ratio, 56.25% We need windmills to power our TVs.

All these fractions started making my head spin 🥴

The best part is when I had to skip back several time before finally realising I still have no idea what is going on.

If run at 2/3 energy extraction, or 59% efficiency, how often does the blades leading edge need repairs, if run at a lower efficiency rate does that increase the lifespan of the blades before repairs are needed and if so ...by how much, and what's the downtime + expenses going to *drag* (sorry) the overall expenses vs. rewards for the windmill? Like you said, windturbines (aka windmills) are endlessly complicated and anything from atmosphere conditions to shape of blades will impact the overall durability and energy efficiency of them. All of this without even considering the impact on local wildlife and its people.

This is called the Betz limit, named for the German physicist who published the mathematical proof in 1919. The magic number is 16/27.