How SMOOTHNESS of a SOCCER BALL affects curve! 

CRAZY cool, Dianna! Anyone remember the Jabulani ball? That thing would do this (speaking from frustrated GK experience)

This was a great follow-up to the other curveball video. The visual with the faucet was very helpful in understanding the difference between laminar vs turbulent flow.

Mind blown. I knew all the little facts, boundary layers, turbulent/laminar transitions, turbulent boundary layers staying attached longer, etc. but I never put them together. Amazing. Thank you so much.

This effect is used in cricket too. Players polish one side of the ball during play to make it swing or curve.

I didn't play soccer much growing up but I played A LOT of baseball. Have you ever heard of a knuckle ball in baseball? It's when you throw the ball with almost no spin and the ball will actually wobble. The faster you throw it, the more it "wobbles." I've always wondered how the magnus effect plays a part in determining which direction the ball will move. Also, I love your videos!

Awesome! As a lifelong soccer player and official I've always wondered about this... Your explanation nailed it, and was easy to understand. Thanks!

This is fantastic physics stuff! Keep on making these!

so can you get a ball whose roughness is between the football and the smooth ball, meaning that it would not curve at all?

Your animations have improved drastically. GOOD JOB!!

Could you do a follow-up video about the different baseball pitches?

Can you try this with the Jabulani? That’s the name of the ball used in the 2010 World cup which had a very unpredictable trajectory according to players. 2 players shined in that tournament scoring free kicks, while other struggled. In some highlights you can see the goalkeepers go in one direction and then turn around and head back because the ball had changed it’s route in mid air. I would love to see a video on how that ball’s design made it so awkward in the air.

Great video! I was in UCSD for exchange for half a year last year and I can't believe I did not know you could be there!

So awesome!! love your videos!!

Very Cool! Love you Physics Girl! Happy Physics Thing!

Hello Dianna! Amazing video once again! Congrats!!😊 Yet, I have a suggestion! How about making a video in which you will clearly explain knuckleball's science (i.e. a very common soccer free kick technique, quite difficult though, where the taker uses no curve and thus the ball takes an unpredictable orbit!!)?

keep up the work. You are one of the only physics and science channel that shows incredible and sometimes complicated concepts in such an easy mannerism to understand. I also want to know do you know veritasium and vsauce

A very interesting post. I did not know it was that easy to change laminar flow. Will have to try this out myself.

Excellent channel, congratulations. Keep it up!

Thank you, that was very cool. I didn't know about the smooth ball effect before. Some of the best Magnus effect results are with a cricket ball. Most balls are completely symetrical, but a cricket ball is not. It has a raised seem dividing it into two hemispheres. I guess the rubber band on the shiny ball has a similar effect. Cricketers shine one side and let the other get rough. That way you can get it to curve either way depending on which way up you hold it and how fast you get it to spin. You can also effect the flight of the ball if you spin it round a horizontal axis. This is also used by baseball pitchers to make the ball stay up or dip depending on which way it is spun. I've read some interesting Ph. D thesis(es?) about the Magnus effect in ball games.

Magnificent Magnus Effect video, Dianna! ❤️

Great video, and top-notch production quality, thank you for making it. I had no idea that the reverse existed, what a wonderful example of regime change. I like Dan's graph of the smooth ball with rubber band, a small change in surface+attack characteristics, a huge change in flight path. Who knew? Do you think that it tends to oscillate always back and forth? In other words, does it go regularly +, -, +, -, +, -? Or is it more like a random-walk back and forth?

best videos on youtube ...thanks Diana

Great video! tx for uploading. Would love to hear an analysis of the "knuckle" ball. C. Ronaldo does it extremely well. Looks alot like the attempt with the small ball + rubber band, where the ball kind of shifts back and fourth. But maybe there is not enough material for an entire video.

Wow! You got John bush in the movie! John Bush's lecture notes on interfacial phenomena are awesome.

The sensitive ball is just moody and wants to go the other way.

Thank you for another interesting video!

Soccer is complicated.

BUT!!!>>>>> A Ping pong ball, which is "smooth" , in my experience has always obeyed classical Magnus effect. do you think mass, size of ball comes in to play? and I meant to mention this when you did the original video!! it answers the question for me thanks!!!

Hey, try learning about the swing and reverse swing deliveries in Cricket... They keep one side of the ball smooth and other side rough and get awesome effects & gameplay!

This literally won't help me in life at all but it is so freaking fascinating to watch and learn lol awesome video!

nice video! I always wondered about this. It all comes down to the surface of the ball then

I've had a few drinks tonight so I'll have to rewatch this video tomorrow which is not really a chore. Right now I'm confused because I figured the normal Magnus effect would have the result of the reverse Magnus effect due to the Bernoulli principle, but like I said my brain error checking is impaired right now so I'm happy I'll need to rewatch the video tomorrow, I'm even happier to get a new channel to watch: fyfluiddynamics.

really really interesting as always fluids are surprising

The Weight/density of the ball will also have a very large effect on the movement. I would like to see this done with balls that are the exact same size and weight but just different surface patterns. I may be wrong but that looks like one of those balls you get from a toy store, those balls also have a weight imbalance at the needle hole which can also affect the motion.

Thank you for using the proper explanation of lift (deflection of mass) and not that stupid Bernoulli's pressure difference explanation everyone always seems to use. This aero engineer appreciates it!

Roberto Carlos vs France - 1997. Magnus effect at his best in soccer game.

Great video !

Can We Use This In Pokemon Go?

I wish I could've learned this type of thing in school. It's so interesting!

When I was a kid in Brazil I used to ask myself every time why such effect happened. Now thanks to this channel I know the answer. Thank you Physics Girl.

I love this I just finished Fluids dynamics and I play soccer in daily basis

This was great!

What really helps me is the mathematical representation. The Magnus effect is equal to w x v (w is omega). Also something interesting to explain turbulent vs laminar flow is the dimples on a golfball. They are designed to create an immediate turbulent boundary layer to reduce the wake behind the ball thus reducing the overall drag force and allowing it to fly father. It is really counter intuitive that increasing the fiction of the air passing over the ball would decrease the drag but that is the effect the wake can have.

is this similar to what is going on when you curve a bowling ball? Or is the friction of contact to the surface of the alley going to change whats going on?

Diana, Thanks for this analysis - great work! I'm using Tracker with my students too ;-) One question: Is the 2:39 shot showing the opposite effect, not the one described seconds before ;-) (should be the orange ball, deflecting towards dashed line - isn't it?)

to decrease the boundary layer of water on our sailboat hull, and increase our speed, we used to sand down the glossy gel coat with fine sandpaper

Nice video. Would you make a video about the Coriolis Effect and how this influence Snipers when they have to perform a long distance shot?

That was interesting, I didn't know there was a reverse effect.

nice work

quite interesting! thank you

Miss Dianna Cowern Simply superb !!

Great video! What about a video on recently discussed Weyl Fermions?

Can you provide a link to the "Tracker" application? The name is so generic that looking it up gives you contextless stuff.

how does the air at the top and bottom of the ball effect where the ball curvs (left / right)???

Dianna Every Day. Get well soon

Great! Thanks for the video. I have been trying to understand how Magnus effect works on 'paper flying tubes'- when thrust forward with clockwise spin from throwers point of view, it gets lift as well as lateral turn, ofyen to left and sometimes to right. I cant figure out how the forward going spinning tube deflects air to get such a trajectory. Can you do a video on that please?!!

So if you added a second rubber band cris-crossing the other in an x pattern would made the magnus effect flip twice? Making the ball curve twice as many times in the air?

Nice video! It got me thinking though...what about those kicks, specially free kicks, that result on the ball not spinning at all. Those have some crazy trajectories on them!

I played with an inflatable beach ball that was very smooth and it happened to curve as expected from the usual Magnus effect. Could it be that the reverse effect did not happen because of the speed of the ball, the size. the distance travelled or something else? (it curves amazingly due to its light weight)

Very interesting video! Does the boundary layer on a smooth ball goes from Laminar -> Turbulent -> Laminar on the side n which the spin is in the same direction as the flow? I guess this depends on the size of the ball.

What were the wind direction and temperature at the time of the experiment? Did these parameters change between kicks?

Very nice vid, Physics Girl! I'm making a science inquiry project about why it can be so hard when passing, curve/bending or even placing the ball on target when shooting it. My conclusion would be that its the way the ball is being kicked. But: for bending or anything that causes the ball to spin, I've come along the fact (from sources like you)that it's the Magnus Effect, or fluid dynamics.(and physical adjustment like how you turn your hips, lock your ankle, etc.)Thanks to your video I now know, but I don't want to copy information from you or any other sources i get information from. Any help?

One of the most interesting video I watched in long time...

I always thought the curve had to do with higher relative fluid motion resulting in lower pressure. I guess this checks out though

What caused the oscillations between normal and reverse imho is that it sometimes rotates parallel to the rubber band, that is, the rubber band is like a rotating disk, and some other times, its rotating parallel to the rubber band circular surface, like a rotating coin. The first one is laminar, the second is turbulent

It also can happen if the mass of the object is lighter the air is transferred in one direction while other is on the other direction.

Is there a surface with the exact roughness required for a linear flight path?

if the force is the same as gravity in some cases then could you angle that force straight up and make the ball efectively be in 0 G for a while?

Would you consider doing a mechanics analysis on heading a soccer ball and the implications regarding chronic traumatic encephalopathy; like what might the brain look like from the moment the body launches to moment of impact? What about rotation of the head right before impact? What about pure forward momentum with no body rotation. Will jumping decrease forces concentrating in the head and neck by transferring linear momentum in the ball to angular momentum in the middle axis of the entire body?

I'm in MSc in Fluid Dynamics. It's weird to leave the university, and watch a video on YT that looks like one my lecture ! ( except that my lecturers are not as good as Physic Girl of course ;) )

Boundary layer transition! My kind of video

Normal balls: Magnes effect Jabulani: hey magnus, hold my beer😎

La solita presa in giro della fisica, all'inizio viene specificato "palla ben liscia" e "elastica" perchè sa perfettamente che se prendiamo una sfera di acciaio molto liscia la mettiamo in ritazione con un motorino, quando sarà investita da un fluido metterà in evidenza un effetto Magnus normale. Che fine ha fatto che DEVE essere elastica? Hanno scordato che hanno detto che deve essere elastica? Semplicemente al di là delle parole non hanno capito il vero perché si verifica l'effetto Magnus inverso, io si.

i actually noticed this when i kicked a smooth rubber ball. i tried to curve it to the right but it curved to the left instead. i have been curious as to why this happens. thank you.

I like the pic of Venice near the Doge's Palace behind you two. I've been there a couple times and I know exactly where it was taken!

You should do this with volleyball. the mikasa MVA200 (olympic ball) has dimples which reduces surface area and causes the ball to move more. whereas the Molten v5m5000 (mens NCAA volleyball) has ridges wich increases surface area and makes the ball move less. pretty cool!!

Would this be the same effect seen in a curve ball in baseball vs. wiffle ball? And does the weight of the balls have anything to do with the direction of the curve?

Hi Diana hope you are feeling better. Just to keep your videos ticking over. Rewatching some. I don’t know if you know but here in Uk we play cricket, when you go to bowl what would be a medium pace ball you try and get it to swing in or out so what we do is shine one side a lot and the other as dull as you can get it so you will see bowlers with there white trousers and a big red mark down there groin area, where you shine the ball.

Next idea. Table tennis with a bouncy ball. It will reverse the spin every bounce, so you can make it go zigzag and if you give it back spin, it will bounce straight up and then when the other player moves in, it shoots forward (sometimes in the face)

Moral of the story is that you have to set your boundaries?

Hello do you know what’s the difference between airball and soccerball a soccerball is heavy than an airball

Hey Dianna, In another video you mentioned how light gets redshifted due to the expansion of the universe, and its energy gets lost. You said this violated the conservation of energy but it still happens. Could you elaborate, or make a video fully explaining it? - Chuck

I thought the regular soccer ball creates a low pressure on the left side due to the faster flow as opposed to the right side which is opposing flow causing a higher pressure thus pushing the ball to the left.

Thats fascinating. Just wondered... I played pingpong with my friend before (hes an expert, but I am not. Lol) i noticed his attacks kinda fall faster than my attacks even though he isnt smashing. And back in high school, i play volleyball. They say when i spike serve the ball, they couldnt always predict where the ball is going because it is "floating". Does the magnus effect also happenes in these sports?

Why does the ball go to the opposite direction of the resultant force?

How would this be applied to throwing a frisbee? Rough vs smooth?

It's all about Diannamics

Cricket ball swing has complexities due to the relative weights and smoothness of the sides of the ball

yeah i noticed that..i didn't know why when i was yonger the ball whent the wrong way but then i tried the same ball and it spined the wrong way.

The F2 found their 3rd member!

i've been playing with soft balls at home and I WOULD GET FRUSTRATED every time the ball acted differently. THANKS to this video now i know why this has happened

What about different fluids? Will mass of the air (eg in helium) affect the Magnus effect?

Make a video about baseball curve too that would be awesome ✨

She sounded so happy when she said fluid dynamics.

Hmmm... What if I wanted to kick the ball and have it curve back and slam me in the face and/or throat???

A famous free kick from Roberto Carlos against France first curved to the right and then to the left. How would you explain that in this framework? Maybe a combination of ball speed and spin?

So every spinning ball always starts with the magnus effect and later on during their path they may change to reverse magnus effect? At least I have not experienced a ball that would start right away with reverse magnus effect. It would mean that the boundary layers had to be laminar and turbulent right from the start.

Didn't think this would blow my mind... I stand corrected

Could you do the same for a knuckle ball?

Hi ! thks 4 Ur videos ! So could you help me please ? I'm very interested in french national sport called "pétanque". For me, to improve my skills, I think it will be better if I master the notions of physics involved in this sport. You have the choice between different metals, weight et diameter of "boules"/ball. You can play on different type of ground. So according to where you play, you have adapt your style : so to "pointer", the best is to roll or throw in the sky the ball ("roulette ou portée") ? Depending the grownd, to "tirer", heat the ball, the best for the path of the boule is a line or a curve ? Thanks if you can help me and try some experiences. :)