What Is The Magnus Force?
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- เผยแพร่เมื่อ 23 พ.ย. 2011
- Whenever an object spins through the air it experiences a 'Magnus Force' due to friction between the air and the object's surface. This force was originally identified while studying the trajectories of cannon balls (though earlier observations of this effect exist). The Magnus force is essential in most ball sports including golf, cricket, tennis, and baseball.
At the end the ball demonstrations were conducted with a 100 mm diam polystyrene ball and the launcher was made by bending a long, thin, aluminum rod and bolting the ends to a block of wood as a handle.
Music was provided by Kevin McLeod (incompetech.com) Scissors and a stock clip from FCP.
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"Do not assume air resistance is negligible."
He is speaking the language of the gods...
I see that we have a spin user here
Coen Ruluked we know everyone’s here to learn the principles of spin and the golden rectangle
People have survived falling out of airplanes with no parachutes due to air resistance. The upward force of air particles colliding with their body reaches equilibrium with the (roughly) constant downward force of gravity, which causes the falling body to stop accelerating towards the surface of the earth and instead reach a terminal velocity of only around 120 mph which SOMEHOW A PERSON CAN SURVIVE (not likely though) which must be a truly RELIGIOUS experience
@@Twelvehourpowernap 😨😨😨😰😰
Ah, air resistance, the so ignored phenomenon in physics. But magnus effect gives it life.
Haha if you think it's ignored you haven't been doing good questions. It's basically exactly the same as stokes law
This is the kind of Physics I'm actually interested in
me too
Me too
Same
Assuming ideal cases each time in physics is just not what I wanted
@@studywithme-z get rekt
@@studywithme-z get booped on mate
The Magnus Force is the force by which you get steamrolled when your name is Ian Nepomniachtchi and you play in the Chess World Championship.
This really explains the trajectory of top spin loops and chops in table tennis
"In chess"
When opponent is sitting right in front of world champ magnus carlsen they experience an absurd amount of mental force and that's what is called MAGNUS force.
i still don't understand the science behind people disliking these videos. who are they? seriously.
Nilesh Suman haha
I think they tried and failed
They think balls are flat
Mentals
And if he turns his head sideways the air will go in one ear and out the other.
libtards lol its racist
Great discussion. I first saw the magnus effect demonstrated in a fluids lab in 1966 when we took our first trip to third year fluids lab. We had pressure tabs around the cylinder and measured the pressure around a rotating cylinder in a modest size wind tunnel. There is a nice CFD simulation on TH-cam which animates this effect in color.
Liked the professors talk.
Excellent illustration! I had no idea the paper tube would be so illustrative. Great job!
I am SO glad I subbed to you. I'm so delighted every time you post. I like learning all these wonderful things you show. Thank you so much!
@scoutmasterkb28 you could think about Bernoulli's in the region immediately surrounding the ball in which case you would say the faster moving air on one side (in the example it would be on top) results in lower pressure than on the other side so this difference in pressure puts a force on the ball - so this is a valid explanation.
U inspire me a lot and I have also started my science youtube channel
th-cam.com/video/HT2sBTbxyQc/w-d-xo.html
Thank you. That’s what l was thinking
The Magnus effect......we study that in 11th grade as a part of fluid dynamics here in india
?
that topic bought me here
I'm in 11 th and finals are beginning soon , 😬
Is it in did you know like stuff??
I’m studying aerodynamic and my teacher is from india haha
Very Informative Thank you for posting, These are the videos that deserve more views.
Roberto Carlos free-kick = Magnus Force
that's the first thing it came to my mind.
Rivelenio inspired Roberto Carlos, and he said it in an interview in world cup in brazil. Rivelenio did it in the 70 when balls were very heavy .. and harder to hit!!
I recently started playing tennis, and i was wondering about the effect of topspin on trajectory.. Exactly what I thought! Thanks a lot !!
Very well presented, your partner is quite clear headed and clearly spoken as well!
Its a shame this isn't taught in youth sports more. I spent hundreds of hours trying to figure out to manipulate a soccer ball and this never crossed my mind. This knowledge seems pretty necessary to making accurate free kick shots.
@someblokecalleddave1 the cricket ball has another force on it due to the seam, or later in the game due to the roughness of one side. This causes the ball to swing toward the rough side. An episode on this is coming up soon.
@veritasium I would be very interested in your take on another cricket ball 'phenomenon' known as reverse swing. Where, in theory, the polished shiny side gets heavier from spit saturation and causes the ball to now swing the other way. Cricket commentators have lots of theories, but rarely grounded in science.
A bit mistake here maybe. I think the ball swings to its shiny side when its old, this phenomena is called the reverse swing. Bowlers like waqar younis, wasim akram and james anderson are few of the masters of this art
That's a nice way to show the effect of the Magnus force. I think I'll use that little experiment to demonstrate it in the future.
What a clear explanation! That gent is really clever!
I took a class on fluid flows and we briefly covered the Magnus Effect. I found slides from one of my lectures that the force had to do with differences in pressures on the top of the ball vs the bottom as it moves through the air. Others have already pointed this out, but to reiterate perhaps in a different way; as the ball moves through the air horizontally air is passes around the top most point and bottom most point of the ball equally. Lets say you hit a topspin shot in tennis. The ball moves through the air and on the bottom of the ball the fuzz(friction) on the ball is grabbing the air and moving it faster. On the top of the ball the friction between the ball and the air is grabbing the air and throwing it against the oncoming air wizzing past the ball. As velocity increases pressure decreases and you have a situation where high velocity but low pressure is on the bottom of the ball and higher pressure low air velocity is on the top. The atmosphere presses down on the ball towards the low pressure causing the ball to accelerate towards the court faster than it normally would with just gravity. The surface of the ball and the speed can also effect if the flow around the ball making it laminar or turbulent which when combined with spin can have some interesting effects. What makes golf balls and table tennis balls different is a good example of that. One other note that most people probably caught but anyways in the video it wasn't really explained why the cylinder moves backwards after being dropped from the plank. It's be cause the body is not moving through the air horizontally but on a diagonal initially so the fastest air relative to the cylinder is on the edge that just left the plank which caused the Magnus force to push down and back + drag as well.
That paper cylinder demonstration is fantastic!
Wow what a neat demo. thanks for sharing that
excellent video with great visuals!
That was a good shot/editing with the paper an the ball, simultaneously falling down. That was "aha" Moment. Thanks!
Thank you for uploading this..
Wonderful explanation
I liked this video and particularly liked the title of Magnus Force ( 1:03 ) and the comparison of the two superimposed on each other ( 1:14 )
If you play any ball sport,this is either common knowledge or cool tricks that happen but you don't understand.
I never understood the science behind the curve ball. Until now.
@scoutmasterkb28 Nope! It's not to do with Bernoulli's because that considers only pressure, gravitational energy and translational kinetic energy, not rotational energy.
Thank you this is so helpful!
will there be an episode about the reverse magnus effect?
I'm doing a project about this subject right now and this video really explains alot!
i hope there will be one about the reverse magnus effect soon.
thanks alot!
Well made video!
That's why table tennis is such an awesome sport. You witness all types of physics if you induce spin on the ball, making the game more interesting.
incredibly easy to understand.
Hi! The experience with the paper cylinder just baffled my students. We compared the cylinder's motion with that of a plastic tube of exactly the same size (by rolling the paper over the plastic tube in the first place).
Thanks for these inspiring videos with Rod Cross!
Btw, 2 small misprints in your introduction text:
experience -> experiences
ealier -> earlier
Are you an english or a science teacher LOL
Awesome!!! I love figuring out how stuff like this works! One question though, is there a way this relates to the leading edge of an airplane wing? In my aerodynamics textbook it talks about Magnus force mixed with Bernoulli and Newton to make lift, but it doesn't really go into how the rotating cylinder through air relates to an aircraft wing moving through air. Thanks!!
I'm 8 years late but I'm confused on the same thing!
my books talk about the exact same thing
Really cool video
great video, brilliant
solid explanation
excellent demonstrations, didn't know any of this... we owe a lot to 18th century British mathematician Benjamin Robins who first discovered this with cannon balls. Forward, back and side spin...
@1veritasium Yes it does! air pressure is lower on the side of the ball /cylinder where the air velocity is greater; hence a side force.
Btw: "there's a force perpendicular to the spin axis" AND to the velocity of the centre of the ball.
For example, the cylinder is not only moving downwards with gravity, it its also rotating. The rotation moves the air, applying the phenomenon seen in the basic graph at 02:00.
The force always acts perpendicularly to the actual movement of the roundish object, which means that the cylinder will actually move backwards.
i am a formula one fan and i always knew about the upside down wing to give the cars more traction, but i never thought about the actual wheels giving the car more traction (downforce). very interesting.
I heard that idea too. It's similar - imagine a ping pong ball spinning clockwise and moving left. Due to Magnus effect it will have a lift. Then imagine the same ball stationary and blow above it to the right - due to Bernulli principle pressure above the ball will be lower than below - we have the same lift!
great video
The swing from a cricket ball bowl is caused by the differences in texture between the left and half sides, in which one side is polished. Still caused by magnus force but not by ball rotation.
you are pretty awsome, i need to see all your videos again, and again and again to get the idea, you are really more interesting than all my teacher's why? beacuse you make this enjoyable and mess up what you think is right. good job keep going
awesome awesome great work
Wow really cool to know that!
I love science! - I´ve looking a ton of tennis videos, top spin, widshield effect and so on...Now I understand the laws behind a sppining ball. I think my game will go up!! By the way great pitching device shown here! ;)
I often hear Bernoulli's principle used to describe the curve of a baseball or golf ball. I'm sure that BP plays a role in both of those cases, but is it the case that the Magnus effect is the larger factor in both of those cases?
awsome video man ur the best
I had a super smooth rubber ball once, and it seemed to oppose this effect. Backspin caused dip, topspin cause lift, and clockwise spin from above caused a curve to the left and vice versa. What explains this phenomenon?
showing this to your friend could be awesome!!!
I'm so glad I'm subb'd to this channel. Thank you so much.
great content
If a cylinder starts rotating clockwise, then at first it is surrounded by anti-clockwise vorticity. This diffuses outwards by the action of viscosity. If there is a crossflow over the cylinder, the anti-clockwise vorticity in the flow is then convected away, leaving the cylinder as a naked clockwise vortex. Bernoulli’s principle then produces a net transverse force, which is the Magnus Force.
fun little trivia, the mangus effect airflow is some what equivalent to an airflow around an airfoil. In fact, in the ye olde day before computer was powerful enough to handle CFD, people used to calculate theoretical lift of an airfoil by using conformal transformation of a spinning cylinder model.
There were attempts to utilize this effect to create VTOL/STOL aircraft, unfortunately the added weight exceed the added lift. So these projects were scrapped
i love these. physics is so cool
clear explanation guys !!!!
And I believe that this is the exact scenario in nature ;rather than going with Bernoulli's equation,....pressure variations...(as some books suggest)
This is easily demonstrated at home using a ruler. The effect of the spin is more pronounced than on a ball. It is also fun to try. Hold the middle of the ruler with the edges between you fingers and your thumb. As you throw the ruler let go with your thumb and pull back a bit with your fingers. It is possible to make the ruler loop around in the shape of a C.
Ya exactly what I thought. Ithink the boundary layer created by the ball is responsible for both of the effect, while the air on the top side is speeding up, it is also always being dragged downward hence the ball "pushes" itself upward.
Just started to , Think about this,,. The Magnus Effect. Learning, some thing , New .Thank You. GP.
Yeah, the Bernoulli's principle probably plays a part with deflecting the air flow, I don't really understand that part in the article, but the actual effect comes from the deflection and conservation of momentum.
Magnus the Magnificent Magnoceros! Cool to see a DotA 2 player here.
3:06 Unbelievable... awesome.
Gotta love that force
This "Magnus Effect" it just a principle of pressure difference. where the airflow is higher the pressure on that spot is lower, and therefore, the object has the tedency to move towards that direction.
Yeah it makes sense. My brain is struggling with the fact that the velocity on both sides of the spinning "ball" is equal. Therefore both should be low pressure equally relative to the perpendicular direction of travel. I know theres a piece of physics I haven't grasped yet, though.
@@richis2fast4u I am no expert, but I guess it is not the same speed because of relative speed, like the both "sides" of a wheel while a vehicle is moving. The ball was moving to the left and rotating clockwise, so the "top" point of the ball had a relative speed vector of the ball speed to the left - linear speed due to the clockwise movement. The "bottom" point had a relative speed of the ball speed to the left + linear speed due to clockwise movement.
@@richis2fast4u Well, in physics we say the speed to both sides of the ball is equal "at infinite", that is, far away from the ball. When studying cases like this, it's fundamental to look at what's happening near the ball, at the distances in which the velocity field is very distorted and the speeds at both sides of the ball are different from one another.
goo.gl/images/i9hfRV
You could find cases in which the velocity field is symmetrical, for example if the ball wasn't spinning, the speeds at both sides of the ball would be identical even very near the ball, and it would look kinda like this:
goo.gl/images/3JNyEQ
In this case the ball wouldn't feel any force perpendicular to the direction of it's flow, of course it would steel feel the drag.
TheMoviemax12 thats bournouli, magnis just utilizes it
I'm expecting a video on balls with seams
Iv learnt this same effect but using the term low pressure on side opposing air flow and high pressure on same side as the ball moving the ball to direction of low pressure side oppside air flow.
This is exactly how lift works on a wing, but instead of spinning it has an airfoil shape to get the circulation of the flow around it. The air travels faster over the top and slower along the bottom of an airfoil creating a circulation which results in lift.
hey @Veritasium, is this explanation correct?
According to Bernoulli's theorem: P+½ρv²+ρgh= constant.
In case of Magnus effect, the velocity of upper surface of object is in direction of air while the lower surface is in opposite direction, due to which velocity of air on the upper surface is greater than that on the lower surface, but due to Bernoulli's theorem if velocity is higher then pressure must be lower, due to which there is a pressure difference b/w the two surface, the upper one being lower pressure( velocity high) while lower one being higher pressure (low velocity), which makes the ball(surface) move upwards in this case!!
I thought I didnt know what a magnus force was then when he showed the cylinder going backwards I was instantly reminded of that basketball dam experiment and soccer players
After 6 moths of I learn mangnus effect finally thanks buddy
That's just basics aerodynamics: lift and drag. Magnus effect itself is the effect that keeps a projectile on it's path since they're already spinning along the longitudinal axis.
That's what I was expecting to see here.
Brilliant! :)
Although I don't believe any have made it past prototypes or flying models, there have been several aircraft designs using this phenomenon, sometimes referred to as Flettner, or Magnus aircraft.
I am regualar watcher of veritasium,but this is the first time i am viewing a video from veritasium because of a homework from my college
finally a new video
Tennis topspin can do some crazy spins.
DO AN EPISODE ON HYDROGEN FUEL CELLS!
@1veritasium I think you're alluding to seam bowling primarily, shutuprafa and I are more concerned with spin bowling which is far more complex as the seam isn't aligned in the direction of flight. The outcomes that we're interested in are 'Drift' and 'Dip'. Dips relatively straight forward, but drift is far more difficult to disect and make sense of - which is my objective.
It is because of a range of different reasons. First of all, the ball is more inert, which means that it requires a larger force to move. The magnus force is only so-so big in this case, and of course, the force will virtually have a larger effect on a lighter object than on a heavy one. Also, since the paper cylinder is larger, it will naturally create a larger force, hence moving more.
the next video seams to be interesting
I would also like to know. According to his explanation of the Magnus force. Why isn't the frontal (left side in this video) of the ball doing the same thing to the incoming air? Wouldn't the spin drags the air upward and hence create a downward force on the ball as well?
Very cool
Does anyone know the name of the metal bracket used to pitch the ball into the air as seen in the demonstration at 2:39? I want to purchase one for demos with my students.
that prof is awesome!!!
So this is what explains the hop up in airsof!
Bullets are only aerodynamic if they're flying pointy end first unlike spherical balls, which present the same profile no matter which way they are facing.
The spin creates a gyroscopic effect, which keeps the bullet from tumbling along its flight path, maintaining the bullet's aerodynamic profile and allowing straighter trajectories.
that's amazing :)
Nine years ago.
Nine likes.
Top comment.
How would you explain the force in relation to your little tennis ball/paper cylinder activity ?
Good job on this video! Keep it up! What about a frisbee??
Reading a lot of comments. It’s crazy to me how bad my school system was in America. It makes sense that I flunked out of college, for most people those intro bio and chem and physics courses were review but dude I didn’t learn anything in high school. I slept through my classes, got straight A’s, graduated top 5 in my school. But came out academically anemic
Hello, where's the video for balls with seams, I'm a Wrist Spin bowler and this stuff is increadibly interesting and I'm currently writing a blog entry trying to make sense of this and come up with some advice as to how to produce more drift when you bowl Leg Breaks.
thanks very much
please elaborate on this. The paintball players of the world would love to hear about objects spinning through the air. This affects their game then any other sport!
Do we have any example of Magnus effect on macro scale? Does the trajectory of objects in the space affected by Magnus effect? Comments, moons, planets, solar systems, galaxys, etc...
Thiago's goal strike against Porto brought me here
I thought I was gonna have the original comment but well, you ruined that for me. Hope it makes you happy 😭