Hydrodynamic Levitation! 

FAQ: 1. This is similar to the Magnus effect in that the relative motion of a spinning ball through fluid creates a force that affects its motion. It's different in that here the fluid starts the ball spinning and there is an equilibrium point around which there are restoring forces. In the Magnus effect the ball must be spinning to begin with and since the fluid is everywhere it can continually change speed and direction. 2. It's not the Coanda effect. The Coanda effect relies on entraining fluid from the surrounding area creating a region of low pressure. Here there is no water surrounding the stream to entrain (since it is a narrow stream). 3. Adhesion between the water and the ball is important - this is what directs the water flow over the ball. 4. The sum of the forces I show should not be zero but equal and opposite to the weight of the ball. Hence the forces of up and out from the initial contact with the stream and up and in from the spray add to make an upward force equal to weight (the in part of the second force is much more important than the up part) 5. It would be interesting to try this with a hydrophobic coating and see if it still works. My hypothesis is it would be much harder. 6. Apparently there are other fountains and toys that use this principle that I was unaware of. This video uses the design created by my friend Blake.

His inner child came out when the ball levitated :)

That ball is more stable than this media platform.

What makes this guy so great at teaching physics stuff is that he is genuinely overjoyed to see how it works.

Legends say that If you say Laminar's Flow 3 times in a row in your RU-vid video Destin from SmarterEveryDay will appear.

Best way to have fun and spray your lawn at the same time!

*that ball is more stable than my grades*

I'm imagining a multicolour disco ball that is light enough to use as a water feature for a pool party.

Wonderful video! Inspired me to make a question on it!

Use an extremely hydrophobic coating on the ball and see how the lack of adhesion changes it.

5:07 my grandparents after I fix their tv by switching it off and back on

That is real magic!

4:52 a wild veritasium appears

Derek, it would be awesome to try this with a ball covered in *hydrophobic coating* - if the water cannot stick to the ball, much less of it will be deflected at an angle, probably making the configuration unstable, right?

2:18 PEOPLE ARE SLEEPING IM MY HOUSE AND I WAS NOT PREPARED FOR THIS

Seeing him laugh and get excited makes me happy!! anyone else?

Drink every time he says 'balls'

I love the child like smile of wonder and curiosity on your face.

Vinay uppal squad where you at 🥶

I love it when Derek shows his "OMG this is so cool!!!" face! It reminds me of little children exploring the world and being excited about everything.

I had never seen this before. It's really counterintuitive, but also somehow makes sense.

Oh come on!!! again! I do a video and when I go to upload it someone beat me to it. :(

I love how passionate this channel and its participants are. It makes it so fun to WATCH, as well as gives inspiration to learn more about each phenomenon and the science behind our universe and its various properties. This channel is everything you could ask for: informative, educational, energetic, positive, and interactive. Thank you, for feeding my love for science for 5 years now.

0:38 I love how his friend was about to say something and he completely cut him out.

Would the ball behave the same way if you coated it with a hydrophobic layer?

it's so great that there are people like you that demonstrate that physics is more than educational, it is fun!!

4:58 He's like an excited child!😃

In this video, the excitement & joy you show for science and discovery is infectious. You encourage us to be just as interested as you are in this kind of knowledge & investigation. That is a great thing. Thanks !

Amazing, Derek. Keep doing stuff like this, and keep your enthusiasm. I'm glad to be your patreon :-)

I love how excited you get for science, that genuine love of the mundane is the main reason I love your channel so much. Can't wait to build my own water spout!

The sheer happiness in this video has made my day. Thank you Veritasium!

really interesting. I love how happy Derek gets over this phenomenon :D

there's a celebration of corpus Christi in Barcelona where they make an egg "dance" in fountains with this very same effect hahaha it's called L'ou com balla if you want to check it out

Dude if you keep glitching the matrix they're gonna unplug you!

I can really see the time and effort put into these videos. Good job man!

This channel makes me happy. All of the videos combined on here. ;) Keep it up!

I absolutely love your videos!

“A hydro what?”- Squidward

I liked the video. thank you Derek. Try posting more videos about different hydrodynamic ideas :) As your videos contain good information to learn and are fun to watch , keep posting them . and good luck!

This is a perfect example of how depressingly important thumbnails are... I have seen almost all your videos (and love them all) but ignored this one for a while... I now feel like a fool because this is one of the coolest phenomena you've shared. Thank you!

flat earthers: impossible

Dude, that was aewsome. Thank you so much! Nice content.

Dear 'Derek Muller" your REACTION IS REALLY INCREADIBLE after disc levitation!!!! I LIKE IT

So early! Awesome demonstration

this is how we'll reach the sun

engineers never grow up. We just play with bigger and more dangerous toys

I know this video is 4 years old but I would love to see this on a massive scale

The force of the spray down cannot equal the force of the water out, the system momentum has to be equal and the sprays in all directions put pay to this theory. In addition this would have no affect on the initial suction of the ball prior to the spin being induced. The actual explanation comes from a common misconception about the lift from airflow being from bernoulli's principle alone. In actual fact a large force comes from the coanda effect, which is the suction caused by the boundary layer on the surface in the flow. If you dangle a spoon from a string and bring the curve under a stream of water under a tap you can see this effect yourself, noting how its not the pressure differential of the two sides of the spoon causing the spoons displacement. This demonstration of the ball in water is much the same. Its the suction of the boundary layer caused by the coanda effect, not the countering momentum of the water droplets, which itself would be minimal. This also helps to explain the natural balancing to bring the ball back into the stream as the effect is exasperated by increased deflection of the boundary until the point boundary separates from the surface and the ball falls from the stream.

Any kid with a hose found this out, It wasn't invented by him.

One of the best youtubers every video I can't wait to watch

Just look at the pure joy on his face at 4:55. That enthusiasm is so contagious, I love it!

I had some confusion about his explanation after watching, so i will explain what causes this effect. The effect is due two an equilibrium of these two phases: A) The ball adheres to the water, and uses its torque to force the adhered water downward and away from the stream. This causes the ball to go the opposite direction of expelled water; upward and into the stream. B) As it enters the stream or expels the water, the torque decreases, and the ball stops moving up and into the stream. The ball then is touching the water at the most outer point on the ball that is perpendicular to the ground, on the side of the stream. The end of phase B actually increases torque and adhesion, which makes the ball move into the stream as the expulsion of water increases. (edit) This is where phase A begins.

This isn't exactly the kind of videos that used to be uploaded, like when I first subscribed, but I suppose this is still content! I can't hate free, science-filled content!

I remember seeing this video and literally saying, "Man, this isn't the Derek I remember..." and after seeing your Veritasium2 channel, this all makes sense. You are among the best, Derek. Take care.

One of the best experiment have ever seen !!

Haha, Derek's like a kid in a candy store.

BOING BOING

your amazement for physics is astonishing keep it up

Probably the coolest thing I have ever seen

This reminds me so much of "l'ou com balla" in Barcelona, it's a very famous tradition here! You should definetly check it out!

+veritasium , I'm not sure if the explanation in the video is properly adressing the physics behind the effect, what do you think of the following following? I think the system works like this: - The water hits the ball (putting forces of momentum on the ball as described by Derek), but also overruling the vanderwaal’s forces of the waterdrops on micro-level, making the water ‘sticking’ to the ball. - We see water leaving the ball as it rotates. - So the mass attached to the ball by surface-tension (vanderwaals forces), decreases as a function of the angle (theta) and the rotational velocity (omega). (Differential equilibrium). {Vanderwaalsforces < m*r*omega^2 --> m_dot (massflow)} - The distribution of the water over the ball is significant in respect to the low mass ball. - Radially the mass moment of inertia of the ball is distributed eccentrically in respect to the center of mass of the ball (the rotation point of the ball), by the mass leaving the ball (imagine the leaving droplets 'pulling' the ball, (local/micro level)) Visualize the ball’s wall is always thicker on the side of the beam (system level). - The sum of the centripetal forces on the side of the beam(collocated-side) > (non-collocated side). The separation of the contribution is located at the center of the ball, which is its turning point. - The equilibrium exists as follows: { Forces of momentum of waterbeam (as function of eccentricity) } + { non-collocated centripetal forces of the water established by vanderwaals forces } = { Collocated centripetal forces of the water established by vanderwaals forces }

Omg that is the most fun backyard sprinkler toy ever.

This actually is incredible to watch, why have I never seen this before haha

Great you just created a doctor strange portal effect

I didn't think the ball was that cool, but the disc... That was bloody awesome!

You can really see the compression dying with these crazy water droplets flying everywhere. This is actually amazing.

OK... Your videos about the cosmos seem like they're mostly trying to fit the most recent observations to some old, highly warped and contingent models. But these videos make it evident that you're actually looking into what's happening and seeing it. Excellent work and presentation.

Alternative titel: Two grown men playing with water and their balls

Awesome! Love it

This gets a like if only for the sake of the amount of excitement Derek displays.

That was a pretty good kick at the end. Good base for tricking.

What happened to sciencium?

I actually think this is a mixture of rotation, surface tension, a force upwards, and the counter force Veritasium mentions. Water hits the ball, starts to push it up, causing the water to cling to the Styrofoam surface, spinning it away from the water source. The rotation of the ball starts to give it stability and so the water clinging to the surface does indeed get thrown off the other side causing it to not stray from the water source, so does the surface tension and ration though. Anytime the ball gets close and hits more of the stream the rotation is slowed down thus just getting pushed by the water it moves outward. Anytime the ball strays too far its rotation speeds up throwing more water and basically wanting to climb the water like a treadmill. Nothing more I can say.

This is the coolest thing I have ever seen

Vertasium: "I will put a link to his video on this right here" I see: "why oppenheimer deserves his own movie"

At 2:14 rip headphones XD 😂

4:54 One day I will know happiness at this level.

U celebrate Science....man.... I can see the child like enthusiasm in your eyes....very good... Keep it up

Amazing video as always!

This doesn't feel like a very fundamental explanation. Why is the force from the water rolled over the ball to the other side that pushes it back in the stream bigger than the force from the water that pushes it out? I suppose bernouillu's law makes up for this difference. Will it levitate if it can't spin?

the tutorial for making it a t home is now a private video and can't by watched anymore :( .

Every video of Veritasium sparks a scientific discussion in the comments. Amazing to see so many different reasons to one simple, often overlooked action that happens in nature!!

i went on holiday and only justgot back andrealisedyou uploaded another cool video i was going to say as the ball was spinning the magnus effect would also help push it into the jet

4:57 this would curiosity and discovery looked like...

Love the Video, but where is the video about redefining the kg?

I heard the physics but I am still in wondering state like wow, this is awesome

seeing you this excited makes me very happy xD

Who else want to replace the ball with Derek

So Awesome! going try this at home :) The linked video isn't working, though

the miracle here is the physics scientist who can actually hit a ball with his foot at the first try!

His friend should produce that commercially! I think kids would have a lot of fun with it and potentially learn something as well.

3:33 You claim there is a return force. I disagree. The fact that the water is carried over and falls off the other side of the ball is not an indication that the water is forcing the ball back to where it was. That is what you thought. That isn't the case. I am pretty sure what is going on has to do with water bonding with the ball and the suction effect it creates upon bonding. You know this bonding from the popping noise when a ball sits in your pool and you yank it out, for example. So what is actually happening is, the water shoots by and some of the water creates a contact point where the water and the ball are now bound. Much like a vacuum. The water, still having momentum, tries to carry the ball up with it. But the ball is too heavy and the bond isn't strong enough so the bond breaks and so ends the vacuum. That leaves the ball behind. Some of the water shoots up and some of the water rolls with the ball. The ball would fall at this point but because more water is hitting the ball, the process restarts. In conclusion, there is no other force beyond water pushing into the ball and then water pulling on the ball as it tries to carry it with it. There is no other force pushing the ball back to the center again. The cause for reset is 100% the vacuum.

Mom where did you leave me styrofoam balls I want to try an experiment

*slaps roof of hydrodynamic levitation stream* this bad boy is so stable you can play frisbee through it

As always, love love love your videos keep it going. Your correct that the water is going up over and around, but that explains only a small portion of the energy transitioning. The majority of the energy is being dispersed opposite of the water jetting at it. If you watch closely, just above where the jetting hits the ball where it is creating a high pressure , you will see just above that an opposite effect (hydro-static adhesion) the accelerated water is being torn from contact of the ball (low pressure) after decelerating it is in the way of the constant incoming water and someone has to get out of the way thus it tumble or skeets off the top... thats the larger amount of water you see leaving the surface compared to the lesser amount creating a rotation (by product of affect)

This vid makes me smile at the thought of doing this with my 5 year old daughter Phoenix!!

+Veritasium : I am surprised that you didn't mentioned the Coanda effect :-/

awesome...keep finding interesting science demonstrations

After watching 'Why RU-vid Used to Prefer Quality', I have realised I have indeed been slacking as a loyal subscriber of yours, but Veritasium Marathon, here I come :)

"Fetch me a hydrodynamic spatula, with uh port-and-starboard-attachments, and turbo drive"