Why Do Boats Make This Shape?

[@veritasium]

It’s amazing to see those waves come together to make the recognizable wake pattern. I didn’t know it would be that complicated but it’s really interesting to think about

[@shaunsfx3845]

Hello

[@pulkitmohta8964]

Can gravitational waves make similar or really different yet beautiful patterns from which we can do some awesome science?

[@rtravkin]

@@pulkitmohta8964 no dispersion for gravitational waves, I guess: they travel at a constant speed _c_ - or at least only a *very* dense matter can change that noticeably…

[@nicepajuju3900]

@@pulkitmohta8964 no because gravitational waves travel at the speed of light and u would have travel faster to create this phenomenon.

[@harshpatel6419]

I think it is time to colloborate man

[@smartereveryday]

Awesome video. Way more complicated than I thought!

[@user-rc8bb7yb1e]

high there

[@kundanborakb]

Yes visualization makes easy to understand.

[@iwishexamsneverhappened]

Omg

[@siramethyst]

Sup Derek

[@sankalp2520]

Just 4 replies? last time I was this fast when I was a sperm.

[@flamingburitto]

Appreciating the fact that i get content like this for free.

[@juliang8676]

This

[@ignacyn5346]

not really, you are paying with your time spent on ads, still its not too much I think :)

[@juliang8676]

@@ignacyn5346 be quiet

[@creativecreepyturtle1562]

Internet bills, your PC, electricity bills, your internet router

[@AwesomeTiger267]

@@creativecreepyturtle1562 the content itself is free

[@kswiorek]

I just noticed that for some time these videos aren't actually hand drawn like the older ones. It took me a while to notice, which means that you managed to imitate the look quite well, but I miss the drawing a bit.

[@2KOOLURATOOLGaming]

Are you sure? I think they still draw some stuff like the boat, water waves and "dispersion" text.

[@matthewhubka6350]

@@2KOOLURATOOLGaming I think it’s tablet drawn with some imitation of a marker. It clearly isn’t hand drawn (if you only include paper in that) when you look at 0:40. They animated the sound waves, and there is no hand moving around like they used to have

[@davidshi451]

On the other hand, this means we get more videos on a more regular basis! There's always a tradeoff.

[@bored_person]

It allows for more complex visuals.

[@NHCH]

If you look at 3:21 you can't tell that that isn't hand drown

[@Barwasser]

0:31 "In this video, we are gonna explain exactly where this shit comes from." can't unhear it.

[@l.w.1014]

I don't even know what he really says. All I hear is shit

[@Oscar-ud8xs]

@@l.w.1014 i think it's shape

[@ArchangelExile]

Lol, I was going to post this too but I think he said "shape".

[@thebush6077]

bruh sammmeee

[@samsalphie]

shift, maybe

[@hauphan917]

Damn, I didn't even notice they all have that pattern. Thanks for making these all contents available for free.

[@theglobalwarming6081]

Years ago when I was riding a boat, I thought about a way to know the speed of the ship I was riding in. I got the idea because I knew that the angle of the shockwave of a supersonic thing relates to its speed, so I looked outside expecting a fine, singular wave. I got surprised about what I found and asked myself why. Thank you for finally answering this

[@codyx8273]

i love learning things i never knew i wanted to know

[@dj_laundry_list]

This is so good that I though I should leave a comment to boost engagement

[@shlok975]

Yeah me too

[@lewisleslie2821]

No way, me too!

[@MetzanV]

Silly KZbin algorithm. I'll do my part for boosting engagement nonetheless.

[@withlessAsbestos]

I though so too

[@silbermund4253]

Hehe same😉

[@igoregalado5590]

It's a bit late at night, but they posted, so I'm now a *wake*.

[@Cumgguzzler]

Bruh over here it’s 9 A.M

[@justanotherhooman7057]

@@Cumgguzzler same

[@vasubhyadiwan7615]

Coolest dad joke I heard in a while

[@NKY5223]

This isnt MinuteEarth. Edit: All puns belong to MinuteEarth.

[@Gamewizard13th]

Mood

[@omercoh2]

0:39 this is a bit misleading, because light waves also disperse when not in a vacuum (which is always)

[@joshuaferry2095]

This definitely not a comment just to boost engagement because I really like this video.

[@ShirinRose]

+

[@animationspace8550]

I appreciate you changing the thumbnail and title to make it more clear what you are explaining here

[@kennarajora6532]

I had no idea he changed the title. Its only been 10 hours.

[@scienceentanglement2180]

Lets appreciete the hours of investigating, animating, drawing... all this for free. Thank Minute of Physics

[@yungmurakami6002]

“Free” as in ads + paid promotion but yeah the gratitude is still there, it works for all.

[@kirabey8946]

@@yungmurakami6002 you dont pay sh*t for this quality content, that means its free.

[@yungmurakami6002]

@@kirabey8946 yes, I know I don’t pay for shit. I’m perfectly aware of that. But the channel is funded through ads and paid promotion. If that wasn’t the case, the quality and time put into the videos wouldn’t be the same, or they’d be far less frequent. You’re underestimating the fact that KZbin is a legit money-making platform. 🤡

[@lilacdoe7945]

@@yungmurakami6002 You're focusing on the creator's perspective. From the user/viewer perspective it is without any cost, especially if you have ad blocker, which means it is free. If OP said, "let's appreciate Minute Physics releasing this for free", you'd be correct, but with their wording, you are not.

[@thephysicistcuber175]

I absolutely love fluid dynamics.

[@LeonBlack666]

These are the questions we never ask but definitely need the answers of, and i can understand how amazingly hard it can be for someone to even think of such a question that is original and not already answered from other bigger channels , really great job mate.

[@sailorgeer]

Excellent video and awesome graphics to illustrate a complex topic in an intuitive manner! I’m an engineer who sometimes does navigation studies (including wake generation studies), and while I’m familiar with the math, this presentation makes the concept much easier not only to understand the physics but also connect the dots between textbook drawings of waves to what you actually see in real life. Well done!

[@2Jackrabbit]

Now I wanna do physically accurate wake shader !! Thx minutephysics you're always amazing and straight to the point and leaving us with just enough to dig through if we want to get deeper, but with the proper terms.

[@foxtp]

Never thought I'd be interested in the physics of boat wakes, but the way you present your content makes literally anything interesting. Great video!

[@kilimanjarocruz660]

This is brilliant science communicating: Very interesting topic explained in an engaging way. Thanks, as usual, Henry!

[@aok76_]

I've always wondered about this and spent any boat ride just looking at these waves trying to figure them out. Thank you for this clear and beautiful explanation.

[@peterzhao3387]

Minute physics finally posts minute videos again

[@tuckerricklefs4830]

You do a great job at explaining complicated things in a way that is understandable. Good job!

[@Ashwini_SK]

WoW!!! fluid dynamics never fails to surprise me.

[@falfires]

This is a beautiful and elegant explanation of an equally beautiful and elegant phenomenon. Thanks

[@JohnSmith-gs4zv]

Wonderful! This was the most comprehensible explanation for wave dispersion I've ever seen!

[@niteshpant1099]

the result was so satisfying that I started smiling at 2:55

[@lonestarr1490]

And I started wondering, why no single videogame that includes swimming or boats got that right so far. It seems not too hard to implement. Would add a ton in terms of visual appeal.

[@jemimahrajakumar7770]

Me too. It's so beautiful. And the way he says it, he sounds like he is happy too 😊

[@eryndil]

Thanks! Over time I'd gotten lost in doing calculations and forgotten what a dispersion relation *really* is. These visual really help remind me of the physics underlying all of the math.

[@joshuahendrickson8694]

I love your concise videos, and this is no exception! I do prefer the old music better with the single bass. Having the music at a low frequency, away from your mid vocal range is less distracting.

[@browzy2000]

Had to do a double take when he said “shit” 😂

[@Zandezz.]

Same here

[@tonydai782]

he said shape

[@shade0636]

@@tonydai782 Source?

[@tonydai782]

@@shade0636 it makes more sense considering what the captions say

[@shade0636]

@@tonydai782 Yeah good point.

[@Apollo_XII_]

At 0:30 it really sounds like you're saying "... exactly where this shit comes from," and I can't unhear it.

[@adamiotime]

This was just... Beautiful.

[@alexmakar9579]

Fantastic visualization of a surprisingly complex topic! Thank you.

[@juliang8676]

Doing a wave motion module at university right now and knowing a little about the actual maths behind this is lovely

[@zane_sadauskis]

Such a simple solution but such a complex idea i love it, great work

[@KnowArt]

really really good explanation! well done

[@PendoraBox]

Finnaly one of my childhood questions are answered. Thank you physics minutes

[@TheScienceBiome]

Ayy you are uploading much more frequently now, it's great to see!

[@TheOskay00]

Learnt about this in wave mechanics last year, but this was a very intuitive explanation. Thanks for posting!

[@ГеррПеннТюх]

So that is how hamon works! Finally, I understood it, not even all 8 chapters of JoJo let me know the exact method, but this channel do.

[@Alexander_Sannikov]

might be overall one of the best short videos on physics out there.

[@MSavva91]

One of the best physics videos I've seen on KZbin

[@kr8771]

i really enjoy the pacing in your videos. and going back to put all the components into one concept really makes for a smooth finish. love it

[@alveolate]

the progression in the video is just so satisfying... you get a buncha video clips, all these simple concepts, lines, wavelengths, and then BOOM you get a 3D rendering that looks EXACTLY like the clips at the start. won't be long before we get a supercomputer to render all the particles on earth in real time.

[@rev_dude]

Another episode of things I didn't know I needed to know but know now after a well made, concise video

[@hemelinger7792]

There are actually some mistakes in this video: 1. Water waves do not travel as depicted and it is not the water that moves in some direction. You can best imagine water waves by imagining someone moving up and down a rope fast. (Wave length there depends on how fast the rope is being moved up and down, the faster - the more waves can be seen on the rope. That is different with water waves. I forgot how sound and light waves work exactly, but I believe light waves actually travel (duality is a word that comes to my mind, but it is too long ago that I have learned this.)) 2. The waves of any water vessel can never be faster. So the person in the kayak will never see any waves moving in his forward direction. There is no bow way moving forward. Vessels always stay ahead of any of their waves (unless they slow down. You have to actually consider that, when you pass under a bridge, where there is little room at the top. You don't want your own waves to lift you against the bridge.) 3. The waves along the side of the vessel travel exactly at the speed of the vessel. It is only when they put distance between them and the ship or boat, they will start to slow down. The further away from the vessel, the slower the waves and the lower the amplitudes of them. I am not sure, but I believe that the Kelvin wave pattern has been refuted. Don't know, if there is a newer model. Real wave systems from vessels are extremely complicated.

[@Alexander_Sannikov]

as a graphics programmer, i will definitely apply it somewhere, and this explanation gave me the exact idea how to do it.

[@pdr.]

At first I thought this topic would be way too hard for me to understand, but this explanation made it so simple! Thanks.

[@tinytwinkels7113]

your all videos are very helpful for all

[@kendallfield9557]

Watching this really made my day. Absolutely wonderful!

[@buckyball2003]

This video reminded me of why I love Physics. Thank you so much.

[@vishwajeetprasad1729]

Great video. Never think about it in this way

[@bralex6669]

Videos like this is why I love this channel.

[@Alexander_Sannikov]

i actually always wondered why the wake does not look like a mach cone, and i assumed that it had something to do with dispersion, but this explanation made it clear why it looks exactly the way it does.

[@forrest7393]

really love the animation. It helps me to understand so much easier

[@bastscho]

The single lines combining to the complete shape is magical!

[@likithstochastic]

Brilliant analysis! I always thought about this, but never in terms of dispersion.

[@TruthNerds]

Very impressive! One little clarification for 0:43 : The speed of sound in an ideal gas varies only by temperature and not e.g. by pressure. Specifically, it is proportional to the square root of absolute temperature, which is the result of particle speeds in a Maxwell-Boltzmann distribution.[1] It varies by altitude because temperature does, but you can't really say it's 343 m/s in dry air at sea level because sea level does not imply a specific temperature. [1] en.wikipedia.org/wiki/Maxwell%E2%80%93Boltzmann_distribution

[@metroidandroid]

that is an approximation

[@alexsalas302]

What a fantastic demostration of how physics is done! I mean, is incredible how a basic result like dispersion yields this apparently convoluted phenomenon. That's what a good physicist finds out!

[@mousammallik7526]

This is good stuff. Appreciate your efforts, Henry.

[@VAM_Physics_and_Engineering]

I always wondered about this ever since I was a child.. Thanks for making this.

[@NihilistEmier]

Look , KZbin notifications does work ! Noice!

[@joshyoung1440]

Video was cool and all but I just wanted to appreciate the use of a very nice iv-I release in the figured bass of your background music. I'm seeing more expressive themes while still working in a universally safe sort of space, well done.

[@jvrcorna14]

So simple, yet so beautiful!

[@bloodspatteredguitar]

It's been a long time since a science video gave me a mouth wide open stunned moment. Thank you Henry!

[@AlexCFaulkner]

that 3D animation was awesome!

[@anipodat394]

It's so cool how the physics behind a boat wake are surprisingly complex!

[@muninnsmith7958]

Yessssssss. I've been studying this!!!! Wooooooooo. I'm stoked to see you make a video on it!

[@jamieNZ]

So insightful! I never knew wakes could be described like this

[@HerrProfDrGuenther]

Just wow. I´m a second year physics student and I never thought about that. It´s very cool and beautiful. I think such beauty gets often lost, while leanring physics. Never the less, physics is great.

[@n49945]

I take a boat to and from work every day. I'll never look at the wake the same way again. Thank you.

[@canozcivelek]

I’m loving these videos! Thanks for the effort. Always very nice illustrations. May I suggest something? It would be great if you did videos with black backgrounds and white drawings. That would be much better for the eye and the battery of the device too ;)

[@robertschlesinger1342]

Very interesting, informative and worthwhile video.

[@Oblic008]

I miss these types of videos that explain simple yet unique phenomenon.

[@kennarajora6532]

yeah me too.

[@KaliFissure]

Nice quick simplification of general principles Maybe on Nebula you explain why an object moving smoothly and continuously through a fluid creates waves at all. How discontinuity develops even if continuous movement. Complex fluid dynamics with Reynolds number, dual fluid interface etc.

[@minhdatcongty7568]

This is extremely wonderful! I love this video! Thank sooooooo much!

[@calmeilles]

Monday's are quite dull in my subscriptions so a new Minutephysics video makes the whole day much, much better. 😀

[@flymypg]

Wakes are also generated by the stern of a vessel, not just the bow. And the longest waves are generated by the ship as a whole (as if from the sides). This makes for a more complex and subtle pattern from which lots of information may be extracted. As the video illustrates, the best way to get this information is via images from above. Which especially includes satellites. A good image will captures the wake when the contrast is highest, which means the lighting must be ideal. In this case, lighting from a 45 degree angle works best. Also, the reflected light is polarized, so even a less-than-optimal image may be improved by placing a polarizer in front of the camera that is adjusted to the angle needed to accentuate the polarization. So, let's say we have a fairly good image from above. What can we learn from such images, even if the vessel itself isn't visible? Here's a partial list: - Speed - Direction - Rate of turn (or lack of turning) - Hull length (for larger vessels) - Approximate draft (depth in the water) - Approximate hull shape (particularly the presence of a bulbous nose or a flat stern) - Approximate displacement All the above may be determined from a single image, without having to see the ship itself! But it works best only for conventional "wet hull" ships: Hydrofoils and hovercraft have different wake signatures that are harder to interpret. Multi-hull ships (catamarans, trimarans) aren't a problem. But what about when multiple vessels are in close proximity, such as for military exercises? Overlapping wakes are much more difficult to decode. There are many tricks that may be intentionally used to limit the value of wake imaging, particularly to make two very different vessels appear similar from above. But assuming no tricks, there are ways to determine much of the above information for every vessel in a fleet, and also do so at night. But it requires filtering out most of the wave data, and focusing only on the elements that most easily provide the information we seek. A great way to do this is by using Synthetic Aperture Radar (SAR), where a satellite sweeps an area with radio waves of specific frequencies, and which also works when clouds obscure the view. Military folks were only the first to do this. Today, cameras and SAR on commercial satellites are used to complement the AIS (Automatic Identification Signal) sent by ships to share their location to avoid collisions. Particular attention is paid to large ships not transmitting an AIS signal, or transmitting an incorrect signal, as it can indicate problems on the ship (electrical failure, piracy, fire, etc.) and trigger a Coast Guard response to investigate. Commercial wake imaging is good enough that even military ships typically keep their AIS active at all times: It is very hard to hide a moving ship!

[@KijasFX]

Awesome and very well explained. I work in 3D and would love to hear more about how you generated this 3D image 3:00. Thanks!

[@gdpvk]

Propulsion's toughest enemy explained to see the beauty in em. Thanks for the content

[@debojyotisarkar72]

could you make a tutorial on how you created the wave line simulation??

[@nikolasscholz7983]

Awesome explanation, thank you! I'm surprised that the dispersion relation seems so simple though. For light in glass those dispersion relations tend to get quite complicated

[@tanvirfarhan5585]

I am watching this while having a online physics class with exactly this discussion going on

[@tommihommi1]

you have class on sundays?

[@asifalamgir5135]

Bangl;adeshi>:?

[@_John_P]

@@tommihommi1 He's probably just catching up, but I had lab work every Sunday for the duration of my engineering course.

[@tommihommi1]

@@_John_P my condolences. Only people putting in crunchtime for their thesis do stuff on weekends here, and the university buildings are closed on the weekend

[@tanvirfarhan5585]

@@tommihommi1 yeah in our country we have holidays only in Fridays

[@jackjac]

I really liked the 3D animation, good job on the visualisation.

[@Cr42yguy]

I knew about dispersion in optics for ages and was still surprised by water wave dispersion.

[@0cgw]

Kelvin's ship wake can be computed using the Chester, Friedman & Ursell Method of asymptotic theory (and hence the wake is described in terms of the Airy function and its derivative). The semi-angle of the cone is sin^{-1}(1/3) independent of the velocity of the ship/duck (for the deep water dispersion relation omega²=g|k|).

[@GeekyMan]

This is soooo cool!😍😍 Thank you for sharing this kind of super cool interesting facts with us.

[@Liugreenslade]

This was both awesome and beautiful

[@assertivista]

A great read to look a bit more into the topic of Waves in Water is Feynman's 51st lecture "Waves". From the Volume 1 of his collection of Lectures on Physics, which is free on the web, made available by Caltech University. Chapter 51-4 is about boat waves. I'm glad it exists. Learned amazing physics. Feynman is a great teacher!

[@nazianahian7868]

that's so complicated as well as beautiful

[@daaknait]

Thanks, this was great. I was wondering about this last summer, as I was watching boats and the wave patterns from a cliff. My SO doesn't share my appreciation of fluid dynamics for some reason though.

[@Chariotuber]

wow this is so cool!! when all those lines added up my jaw dropped

[@moicr96]

The animation is amazing

[@kaustubhhirve7734]

simply fantastic

[@stephanieparker1250]

Great way to “wake” up, a notification of a new Minute Physics video! 🙌

[@kennarajora6532]

I see what you did there, clever.

[@UnlaunderedShirt]

Awesome video! Super clear and concise! Keep it up

[@tdmmcl1532]

the pattern is interesting. now, here the hard question: other than speed and the density and depth of the water, what causes the period of the waves? in other words, what is MOST attributed to long period, fast moving waves versus short period, slow moving waves. remove the speed of the boat, and accept that density and depth of water are moot. What actually creates the frequency of the wave? hint: displacement spoiler: consult a naval hydrodynamic engineer before guessing. for another clue: examine pressure waves from submarines and inspect the differences above the hull versus the difference below the hull.. if you are thinking about "lift"...you are getting close.... if you are now thinking that the layer between water and atmosphere contains clues, you are even closer. have fun with this one.

[@relariis_the_paradox]

So that spawns an interesting question: if dispersion of waves of different speeds exist, are all the differing speeds emitted from the motion simultaneously, or are the water particles accelerating and thus creating the wider waves longer after contact? That would explain why the wake feathers outward more further from the boat instead of closer to it

[@miguelrezende8479]

Very good video, the reason is purely mathematical but you can see clearly this patterns of nature c: and I imagine you can also associate this with hyperbolic functions and get the beaulty of this kind of study, frequently just abstract

[@InformatrIIcks]

That 3d animation is amazing !!!