I can't believe I didn't make a "how the turntables" joke. That's why I love the comments section! Here's a paper with the calculations: m2.askthephysicist.com/Weltner.pdf Note that equations 18 and 19 should have R² terms. That threw me off for longer than I care to admit!

@GaborCsorvasi

Жыл бұрын

What happens with shapes of constant width? My guess is it depends on it's moment of inertia, but still would be fun to see.

@isaacm1929

Жыл бұрын

Spinning balls. Balls on the table. You could've done so much jokes... Have a great day sir! Also, Baller, Balling.

@brianm6337

Жыл бұрын

Does this work with non spherical solids, too? How about a water filled ball?

@calholli

Жыл бұрын

It's hilarious to say that the car is pointing "tangentially"-- When in fact, no matter what direction you point the car on a round table, it is pointing OUTWARD; lol.

@fookingsog

Жыл бұрын

Our family used to have a membership to a children's museum where they had an exhibit similar to this. The spinning disc platter was probably 3-4 feet in diameter stainless steel. They had a variety of different diameter and thicknesses of disks that you could experiment with and balance on the big spinning disc platter. Was probably my favorite exhibit as it required intuitive interaction!!! Super Fun!!! 😁👍🏻

I'm gonna need a 2-dimensional, transparent, liquid filled representation of this.

@lyricsassam

Жыл бұрын

😂😂😂

@furzekoenigin

Жыл бұрын

It's the only way for me to understand these things.

@swedishpsychopath8795

Жыл бұрын

Could we settle for a venn-diagram instead? So Kamala will understand too?

@appalachianforge7537

Жыл бұрын

Sucks for you

@philipfahy9658

Жыл бұрын

We used to use a tank on a rotating table like this with food coloring to simulate solid body rotation in undergrad. So 3d, but transparent and liquid filled, we're almost there!

'discs behave wiredly on turntables'... that sums up my entire experience of the 90's quite nicely

@scottmatznick3140

Жыл бұрын

Weirdly

@SirNobleIZH

Жыл бұрын

Wiredly

@ferrumignis

Жыл бұрын

You can get Bluetooth turntables now, so the discs behave cordlessly.

@fluffigverbimmelt

Жыл бұрын

"90s" "turntables" "behave wired-ly" Hm, am I overthinking this?

@leahcimwerdna5209

Жыл бұрын

You spun them the wrong way

Well well well, how the turntables....

@past-tense-of-draw

15 күн бұрын

Underrated comment

This is the first time in a long time that I've genuinely felt fascinated by the application of mathematics as hard-and-fast rules for how our world works. Thank you for this fascinating journey.

I can't be the only one that initially thought it was pi rotations rather than 7/2 when you counted them

@sudoscoobs1373

Жыл бұрын

Same! I was sitting here like, "do I smell pie?"

@isaacm1929

Жыл бұрын

I was also thinking pi rotations!

@dav1dsm1th

Жыл бұрын

@@sudoscoobs1373 Great. Now I'm hungry.

@HassanSelim0

Жыл бұрын

same, it's a very likely place for pi to come jumping at you 😁

@DrakiniteOfficial

Жыл бұрын

Sad to say I didn't think of that. I was just confused at how the heck 7/2 seemed to appear.

Would be cool to mount the top-down camera to the turntable so it rotates with it. When you mentioned the non-inertial reference frame stuff I was hoping to see the ball’s path from that reference frame.

@dustinandrews89019

Жыл бұрын

Yes, I very much am interested in that. My intuition is that it's elliptical orbits that resemble orbits due to gravity. Though, maybe it's more like anti-gravity since the force on objects is outward unless they can roll.

@mrjbexample

Жыл бұрын

-Look up hypocycloids, they are star-like shapes that form if you trace a point on a small circle rotating within a larger circle. I think the ball's path from the table's reference frame would be look like one, with k=3.5 or 7 points to the star.- EDIT: this is wrong, it will just be a spiral that moves inwards then outwards and joins up with itself

@jetison333

Жыл бұрын

its possible to just stabilize the video on the turn table, if someone wanted to put in the effort.

@PhysHow42

Жыл бұрын

@@dustinandrews89019 he mentions in the video that it cuts a perfect circle in vacuum without slippage, and a spiral with slippage.

@MrDaraghkinch

Жыл бұрын

@@mrjbexample spirograph?

Seeing you advertise "The Länd" took me by surprise. I didn't know we were advertising internationally. Also, your pronounciation of "Baden Wörttembörg" is really adorable. 😄

@linkerganove5756

Жыл бұрын

Nett hier aber waren sie schon mal in Baden-Württemberg?

@niklasfischer7866

11 ай бұрын

LOL was about to stop watching the video but now I’m gonna keep watching

The hollow ball discrepancy blew my mind. And the seeing the mathematical proof was so satisfying. I love when maths describes real world phenomenon so comprehensively.

Your videos are simply awesome

@evaakter6425

Жыл бұрын

Very helpful

@supriyanto8401

Жыл бұрын

Thumbs up

@nazkhan3506

Жыл бұрын

👍

@ethanmanman8867

Жыл бұрын

Hello verified user

@misssusmita2502

Жыл бұрын

Very good

as soon as you brought up a hollow ball and I saw the numbers 5 and 7 pop up, I thought of Moment of Inertia. I am pretty proud of my tiny noggin for thinking of that

@davidetosches6014

Жыл бұрын

same. I also thought at Cv and Cp of ideal gases but then I excluded then because of the context (though, it's still spinning stuffs and inertia ;) )

@RestWithin

Жыл бұрын

Noggin! Now that’s an old word! Mate you’re showing your age! 😂

@MyriadCelestia

Жыл бұрын

@@RestWithin i am probably younger than you think haha

@squigglycups5666

Жыл бұрын

​@@MyriadCelestia atleast 80

@ezfzx

Жыл бұрын

It is precisely related to the inertial moment, confirmed if you examine the paper. We try to express the equation as: I = k m r², with k = 1 for hoops, of course. We have a lab the student do that rolls different types of balls down a rail of variable separation and they have to predict the speed in terms of the "k" value. It's very enlightening. As a lab, this would be equally fascinating.

Would have loved to see a view locked to the turntable's rotation (i.e. a camera from above rotating at the same speed, or each frame rotated to keep the turntable apparently in a fixed position). Bet the ball movement would look pretty interesting.

@trif55

11 ай бұрын

This would be great! Also this video's a decent explanation of orbital mechanics, where poking it inward to where it's moving faster etc

@davidwuhrer6704

8 ай бұрын

Seems simple enough to deduce what it would look like. For the ball staying in the spot, it just describes a circular orbit for the table. For the ball going in a circle, it would be an elliptical orbit precessing one seventh with each turn, so that after seven orbits it ends up where it started again. Or five if the ball is hollow.

@batlin

8 ай бұрын

@@davidwuhrer6704 it's not that I can't figure out what it would look like, but it would be enjoyable to see.

@davidwuhrer6704

8 ай бұрын

@@batlin That it would be.

As a physicist, this video is pure joy. Thanks for making this video available, Steve ❤️

Love the video! Wanted to say, I did my master's thesis on how students conceptualize the Coriolis force, and I'd recommend avoiding terms like "fictitious" when describing it. It gives students the impression that it's 'made up' or 'doesn't exist', which conflicts with their bodily perceptions which have experienced the force first-hand. Also, it makes it sound like it shouldn't be trusted (let alone, used), rather than emphasizing how helpful (and necessary) the Coriolis force is when viewing things from a non-inertial frame. Personally, I try to call it an "apparent" force, because it 'appears' when you change your perspective to the non-inertial frame. It's all about clarifying the contexts in which the Coriolis force is productive.

@SteveMould

Жыл бұрын

That's a really good point, thanks! How about virtual force? I quite like "apparent" though.

@insidejazzguitar8112

Жыл бұрын

@@SteveMould you could call it the Coriolis effect

@PeskyTheWabbit

Жыл бұрын

@@SteveMould One of my hobbies is long range rifle shooting, so as you could imagine, the Coriolis Force / Effect becomes a factor in my accuracy. When you said "fictitious force" in the video, I definitely raised an eyebrow before I reminded myself that centrifugal force is similar in not being a real "force", because I have definitely witnessed the Coriolis Effect. I feel like "fictitious" can cause a knee jerk reaction. I think "apparent" would fit perfectly, or simply referring to it as the Coriolis Effect, as that does not imply any "force" is being added to the equation.

@jannegrey593

Жыл бұрын

@@SteveMould Especially since Flat Earthers will use it as "proof" that Coriolis effect isn't "real". Apparent force is much better. Same for Centrifugal Force.

@LeoStaley

Жыл бұрын

@@SteveMould "emergent" is often used to describe effects which are not fundamental, but arise as a consequence of other more fundamental effects.

This helps me visualize how a Lagrangian orbit can be somewhat stable despite all the forces being apparently unblanced.

@pineapplepenumbra

Жыл бұрын

Good point.

@ThreesixnineGF

Жыл бұрын

Yeah that's kind of how JW telescope keeps orbiting around it's lagrangian center. Although its path is an 8 figure rather than a perfect circle. Which make me think that this 8 figure (lemniscate) might be a 3D substitute for the 2D circle. But idk

@JamesHawkeYouTube

Жыл бұрын

The sky is not "outer space". Sorry to break the sci-fi illusion. "Gravity" is a pseudo-scientific belief about balls of matter in the sky.

@brunnomenxa

Жыл бұрын

@@pineapplepenumbra, Good Lagrangian point.

@Astromath

Жыл бұрын

That's exactly what came to my mind immediately when he showed the circular orbit of the ball that doesn't go around the center!

I saw this at the Experimentarium, a Science Museum in Denmark. One interesting variation is a large hollow ring (a thick bracelet or similar). If you put it on the turntable vertically and let it get up to speed, and then place a ball inside the ring, the ball inside will stabilize the motion of the ring, and behave quite similarly to a single ball.

I like that you showed some of the math here as well. I think too many youtube science channels forget that besides just describing observations we also already have a lot of very good models that can predict the observations very well.

I imagine the formula for the motion of a slightly elliptical ball would be terrifying.

@lucasbakeforero426

Жыл бұрын

I am getting nightmares already.

@StigFerrari

Жыл бұрын

It can’t hurt you

@santoslkwjs4718

Жыл бұрын

yesss kzread.info/dash/bejne/lIGsr9ebhtSZZZM.html

@shadowcween7890

Жыл бұрын

The truth is that any real world ball is already slightly elliptical, since perfect shapes are nearly impossible to create

@daty1453

Жыл бұрын

​@@shadowcween7890 why are u saying nearly

I really liked how the equations are presented here. Must have been a ton of work. Thanks for making the effort.

This was such an interesting video. I don't remember any of my alevel physics but I do love stuff like this

Most of us would, I think, be surprised to see a ball on a turning turntable basically staying in one spot. Instead of explaining with formulas only, you described how it happens very simply. Great work!

A ball rolling from a flat surface, onto a turntable, back onto a flat surface, is also interesting. It swerves on the table, but exits perfectly in line with the direction it entered from.

@erikeriks

Жыл бұрын

Modern scientists: it exits perfectly in line with the direction it entered from. The line in question: 5:32

@Call_Upon_YAH

Жыл бұрын

Jesus Christ is the propitiation for the whole world's sins. They that believeth and are baptized (with the Holy Spirit) shall be saved; but they that believeth not shall be damned. Those led by the Holy Spirit do not abide in wickedness. 👍🏾 *God is ONE manifesting himself as THREE;* the Father, the Son, and the Holy Spirit! Bless him! *For these three are one.* As I am led by the Holy Spirit, nothing I state is a lie, but the truth of God. Anyone who tells you differently is misinformed or a liar. They do not know God, nor led by him. Anyone who *claims* to be a Christian and is against what I am doing, and where I am doing it; the Holy Spirit does not dwell within them, they lack understanding. They know not God, read his word, and their religion is in vain. Do not hear them, they will mislead you, the lost cannot guide the lost.

@Call_Upon_YAH

Жыл бұрын

When you trust in God and cast your cares (worries, anxiety, depression, suicidal thoughts) upon him, they will be NO MORE! Know that there is power in the name Jesus Christ! His name casts out demons and heals! The world is wicked, evil, and of the devil. I too, was a wicked sinner of the world before I opened my heart to God. I am living proof of God's work and fruitfulness! He is an active God who hears the prayers of his! God's children are set apart (holy) and righteous. The devil is a liar that comes to steal, to kill, and to destroy; that includes your relationship with God. Open your heart to God, repent of your sins (he will forgive you), and let him direct your path. Draw nigh to God, and he will draw nigh to you. Cleanse your hands and purify your heart, lest you walk with the devil and follow him to hell.

´been listening to this half asleep and it’s so brilliantly narrated that I’ve recorded the video in the watch later list. Steve is one of the very few best science sources on youtube and better than very large institutions that allocate large sums of money into it. Steve has the knack of finding sufficiently mundane stuff that anyone can relate to, yet is scientifically relevant and catchy. Steve, you’re the boss. Thanks a metric ton.

Very good at cutting out the technicality and still keeping the explanation satisfactory

I started chuckling to myself the second I saw the equation for the moment of inertia of a ball. This was so cool! It's nice to see some interesting physics can still be done with closed form equations.

@lukedowneslukedownes5900

Жыл бұрын

I’m curious. What is your thoughts on open and closed formulas relative to physics?

@dickJohnsonpeter

Жыл бұрын

@@lukedowneslukedownes5900 Equations are closed, formulas are open.

@ratulxy

Жыл бұрын

@@lukedowneslukedownes5900 by closed form equations they mean that the equation can be solved analytically which generally leads a nice solution. Otherwise you have to solve it numerically.

@pineapplepenumbra

Жыл бұрын

@@ratulxy It helps that your post was good, but I thumbed you up before I read it, just because your name deserves it.

@ratulxy

Жыл бұрын

@@pineapplepenumbra haha, thanks!

Your videos are simply awesome! I am a rerired Physics Teacher and could have used your videos to engage and challenge my students while I was teaching. I never miss your videos and thank you for keeping my love of Physics alive and I hope inspiring a whole new generation of young students to take up the challenge of physics and science in general.

@aze4308

Жыл бұрын

your videos

Amazing video. I have a doctorate degree in Physics and I am always amazed with your videos. Kudos and thanks for the link to the paper.

You keep fascinating us as well as entertaining. Thank you for that Steve. And congrats to those, who choose you to promote "THELÄND". Perfect choice. I am from Germany and have seen the clip before. And yes, I believe for tech or science aspiring people, that is a perfect place to go to.

@Norsilca

Жыл бұрын

Yeah I loved that his sponsor was a state of Germany!

It's always delightful when a simple experiment reveals unexpected behavior.

When I was a kid, the Fort Worth Science Museum had a 6-ft radius stainless steel turntable set flush in a table so there were no pinch points around the edge. They had all manner of round objects for kids to play with. I remember my parents saying it was time to move on, but I was mesmerized playing with wheels and balls on the spinning table. Good times

Ok dude, you've grown on me and I love these videos. Thanks for getting on with it and having the balls to just make the videos!

Your 'paradox' videos are my favourite ones, Steve

Watching this video almost 40 years after I dropped out of taking Physics and Maths for A-level, I'm glad I did. The overlying description of what's happening is utterly fascinating, but the calculus, the physics, the number-crunching... it was never going to be for me. I absolutely LOVE the passion you and others have for such things, because I have my own 'things' which give me joy. Glad to be a viewer, amazed to catch of a glimpse of something described in a way I can understand it, knowing that you can do the maths and the physics and I don't have to!

@frightenedsoul

Жыл бұрын

There was a time around 6th-8th grade learning high school level algebra with a very good math teacher that I really enjoyed it mostly because the teacher made me understand it and therefore I was really good at it and had really good grades as a result. Fast forward several more years and terrible math teachers later and I was never able to successfully advance past that and had terrible math grades by the time I got into college.

@occupyallthethings

Жыл бұрын

Lol I'm the opposite.. didn't drop out and got a mechanical engineering degree and lots of regret

@dark6.63E-34

Жыл бұрын

@@occupyallthethings can you elaborate? I am a first year in mechanical engineering and maybe i could get some insight

@shet3930

Жыл бұрын

this is a typo and you meant to say 4 right?

@thitam5003

Жыл бұрын

ok

Would love to see a camera view mounted to the turn table. I assume the the ball would appear to trace a pattern like a spirograph.

@better_dead_than_red

Жыл бұрын

I got a nausea from this idea

@levetbyck

Жыл бұрын

maybe have a sensor inside the ball

@RoyceRemix

Жыл бұрын

As soon as I saw your comment I knew I had to make it happen - Here's a handful of shots from the video that I tracked, and one shot that I traced the path of the ball, I put my thoughts about it in the description under the video (unlisted, but still sharable) - kzread.info/dash/bejne/X52FrM-Jn5TahNY.html

Watching this after taking physics and this actually makes so much sense. This is actually very similar to rolling an object down a ramp, and that’s where the 7/2 ratio comes from The moment of inertia times the lever arm.

@johnsomerset1510

Жыл бұрын

I guess you failed physics then.

@soanywaysillstartedblastin2797

Жыл бұрын

@@johnsomerset1510 got a c-

Centre for Life in Newcastle had a massive turntable (not sure if it still does) with lots of objects you could experiment with. We practically spent all day on it it, it was great fun. 😊

Classic Mould. Breaking an interesting phenomenon down to easily understandable parts. It makes me feel smarter than other channels because it's like he is just making me realize what I already know opposed to teaching a whole new concept.

@paulshuttleworth6261

Жыл бұрын

Also very willing to admit he doesn’t fully understand it either. Humanises him. Great guy.

@rgw5991

Жыл бұрын

OK

I love how you can see the line bent with the rolling shutter effect when he pauses the video. So cool

@user-ke5xq3cs6i

Жыл бұрын

👆🏼👆🏼congratulations fan, you've been successfully selected....contact me on the above nicegram name to claim your prize

@levetbyck

Жыл бұрын

this part 3:08!

Steve Mould is the perfect example of how to make science interesting and engaging for the laymen and encourage curiosity. Asking questions about even the most mundane of observations and interactions is invaluable. We don’t know what we don’t know until we ask why and how.

Dude, the math explaining the 7/2 was so beautiful. It made me smile!

I love that at 3:20 we can see the rolling shutter make the line curved

I swear you always come up with the most mundane topics that slip right by the rest of us, and yet are so very fascinating when you take a closer look at them. Another amazing video.

You’ve done a great job of contributing something for all of our benefit.

The moment you mentioned it was a different, but nice number for hollow balls immediately made my mind jump to moments of inertia

I don't think I've seen a Steve Mould video I didn't like, but this might be my favorite. I was slack-jawed in surprise for a lot of it. The way the balls moved really was unexpected and quite pleasing as well.

Wow, this takes me back to the 50;s. We had a record player that didn't work (the audio didn't) but the turntable would spin. We'd put on a 33 LP and put a marble on it. I observed the same results as you did but had no understanding of the physics/math involved. Thanks for the excellent explanation, BTW, we would also roll up a paper cone, stick a straight pin through the pointy end, and hold that on a record to listen to our tunes. Way cool. Just sane... :^) Saint

@richardchambers256

Жыл бұрын

Me too but I used a CAT. 😆

@eugenesaint1231

Жыл бұрын

@@richardchambers256 Ha! 7 to 2 ratio, 7+2=9 :lives. Coincidence? I think not. He he he...

@alphonsbretagne8468

Жыл бұрын

I did this when I was young as well. The paper needle trick works with a flat paper or cardboard already but slightly quieter. Though the best thing always has been to choose the wrong speed 😅

@jhawkins4412

Жыл бұрын

Dito

@jpsned

Жыл бұрын

My little sister and I used to use an empty dog biscuit box and a needle to listen. 😀

This was so nicely presented. Great video.

In Bremen in Germany there's a science center called "Universum" and it has a spinning metal plate like that, with some differently shaped cylinders. One of the most intriguing physical phenomenons and I never fully understood it so far. Even with a master of physics. Actually still now after the video.

Amazing video, as always! I've never commented here before, but I'm a long-time subscriber and wanted to say that as a researcher in physics, your curiosity is simply an inspiration to me! Also, I love your plug for THE LÄND (Baden-Württemberg), which is where I did my undergrad. It's a great place for Science indeed!

@danielsieker9927

Жыл бұрын

Let me guess, Heidelberg?

@adrianvankan7619

Жыл бұрын

@@danielsieker9927 That's right!

I would like to see an Eulers disk spin on a spinning turntable. Once when the disk and the turntable both rotate in the same direction (e.g. clockwise) and once when one rotates clockwise while the other rotates anti-clockwise.

@user-ke5xq3cs6i

Жыл бұрын

👆🏼👆🏼congratulations fan, you've been successfully selected....contact me on the above nicegram name to claim your prize

@philb4462

Жыл бұрын

@@user-ke5xq3cs6i You are a scammer. Messages like these are cropping up all over KZread.

@Willy-the-Fire-Putter-Outter

Жыл бұрын

The people have spoken!! These are our demands, our balls are in your court!

the first two minutes of this video is pure magic, not a single second i got something i expected

As someone who is really into frisbee golf and also into physics I can confirm that there is correlation with the gyroscope and the tilted turntable. The reason for the gyroscope moving is because as you push it your input travels around the gyroscope with the rotation

Just realized you went from finally hitting 1M subscribers a few months ago to being on the verge of 2M right now. Well deserved! And as always great video :)

@user-ke5xq3cs6i

Жыл бұрын

👆🏼👆🏼congratulations fan, you've been successfully selected....contact me on the above nicegram name to claim your prize

@ShainAndrews

Жыл бұрын

Right.. because it matters.

@william41017

Жыл бұрын

@@ShainAndrews Jesus! Op just congratulating him on his success. And, idk about Steve, but subs number matter for a lot of youtubers considering that's their livelihood.

I like thinking about your videos like they're a published study in a scientific journal. Love the idea of the conclusion of a paper being, "Balls and other round things behave weirdly on turntables."

Hi Steve. Great video, really enjoyed it. I'm working on a similar type of educational videos. Did you use a professional editing tool to draw the velocity vectors or is it freeware? Thanks for any suggestion on editing such videos. Cheers

The Linik you are talking about in 8:14 is the change of angular momentum-> you can use the right hand rule to obtain the direction of deflection Example aircraft with one jet engine : Your right hand "wrap"-fingers are pointing in the direction of the engine's rotation-> your thumb is now pointing out of the engine Lets assume the jet is pulling nose up Imagine the line that your thumb draws now use right hand rule again-> your thumb is pointing in the direction of the change (up) and your "wrap" fingers show you in which direction the moment is introduced So in this case the airplane would yaw to the left (if the pilot is sleeping)

0:52 thanks for the ball to hand size clarification here. 🤣

@mattybrunolucaszeneresalas9072

3 ай бұрын

They are not normally that size?

As a 70 year old chartered engineer I am always learning new things. I had never seen this before, so thank you.

When I saw this I was reminded of Lagrange points and how objects near them have stable orbits around them even though there's nothing there. Of course it's the same - another example of the Coriolis force. Great video, thanks!

I actually made a Game Jam game around this idea. You basically control the bigger spinner but you are the ball. You try to dodge obstacles and collect power ups and stuff. It kinda worked but it was still a neat idea and a fun thing to do.

The circular motion of the ball reminds me of the motion of an object in space orbiting a planet. If its orbit isn't circular it gains velocity as it decends, and then exchanges that velocity for altitude after periapsis. I have probably played too much KSP.

@danwood1121

Жыл бұрын

I wonder if this is related to how the James Webb space telescope has that unique orbit?

@MattStryker

Жыл бұрын

Steam says I've played KSP for 3,310 hours. And yet, when I get home tonight from work, guess what program I'm gonna fire up...

@NateTheScot

Жыл бұрын

He has a video on that exact thing. Or at least I've definitely watched a video explaining why the orbit of planets and bodies are all evenly balanced because of oval orbits since it's extremely rare for an actually perfectly circular orbit due to universal gravitational pulls. This results in all orvits eventually balancing at a certain point in the oval which can lead to interesting alignments on very rare occasions which I'm fairly sure was him since I don't watch many other channels like this but I could be wrong..

@Aashishkebab

Жыл бұрын

Unrelated

@RichardHowells1234

Жыл бұрын

Fink dat so

Watching the ball on the turntable is mesmerizing!

You explain things so much better than Veritasium, which I greatly appreciate.

I'm interested if a similar effect would occur with other solids of constant width. Really cool video, as always, and I enjoy learning from them!

I'm so glad you mentioned something about coriolis. That's kinda where my mind went watching the ball go from closer and further to the point of rotation.

@feedingravens

Жыл бұрын

Not only that - when I see the ball orbiting around a point, it reminds me of a moon. Almost as if it does not even need a planet to do such movements, or, all the planet does is give the cause for the orbiting moon to orbit another center.

@dustinkirk3920

Жыл бұрын

@@feedingravens except, the moon isn't rotating on its own axis is it? Planetary satellites orbit their hosts regardless of their own spins. Hmm...

@truongtran-sl6rh

Жыл бұрын

ok

@fotwen

Жыл бұрын

@@truongtran-sl6rh alrighty then

@fotwen

Жыл бұрын

@@feedingravens idk... Remember, the center of orbit between moon and earth isn't the center of earth.. so their orbit is a relationship between the two. The reason it's tidal locked with earth is also that reason. Adding friction to rotating bodies it completely different than orbital mechanics. As I know of. That ball is experiencing different tangential speeds as it moves closer and further away from the axis. Orbits do have a sling shot kinda effect. But I see that different than this. But I could be wrong.

Hi Steve, there's lots of fascinating ideas here that would be cool to explore. For example, if the spinning surface was curved like a Euler's disk, how might the motion differ compared to that of the flat or convex surfaces? Here you present flat, and earth is our convex. This harkens back to your "this should slip off but it doesn't" video with spinning concave and convex surfaces and a spinning band. Love the videos and making us foster unique concept connections!

Trigonometry of forces applied and varying velocity of the rotating table. Crazy how simple the equations are with so many complex actions happening.

Wow, amazing video!!! Love your work, the experiments and the clear explanations.

Fascinating stuff, very well framed in images and clearly explained. Thanks for your video!

So strange how our intuition of where the ball goes kinda depends on the ball realising it's on a turntable and behaving accordingly. I loved that point of your explanation.

This has such great timing, for me, as for the question I had in my mind, about the Harry Styles , Music Video, As It Was, music clip has him walking 🚶 or running 🏃‍♀️ around on a turntable, although with another blue,red vector possibly. However where I am going with this had answered a question for me, thank you. 🎊 😊

Steve, this is very fascinating. I really appreicate. I am guessing that, near the surface of the turn table, there is general tendency for the air to flow from the center of the turn table towards the edge of the turn table. The reasoning is that the surface of the turn table moves faster as you move from the center of the turn table towards the edge of the turn table, and, thus, air moves faster as you go from the center toward the edge of the turn table, which, in turn, means air pressure becomes lower as you move from the center towards the edge of the turn table. I thought it would be fun to observe and analyze the roll of air flow near the turn table surface and around the ball. Also, I would really love to see you conduct the same experiment you did in this video in vacuum just to see whether it makes any difference.

I've seen this done with an umbrella as a bit of a parlor trick - good to understand how it works

@Loctorak

Жыл бұрын

That IS a cool parlor trick!

Brilliant stuff, as ever - loved finding out where the 7:2 ratio came from!

The contact point on the turntable, if not assumed to be a point but rather an area, would be roughly circular and the radially outer portion of it is rotating faster underneath the ball than the radially inner portion of the contact area. But the circular contact area on the ball which is rolling tangentially cannot be faster on the radially outer portion compared to the radially inner portion. So this would induce some slip i assume cause the ball can't start to rotate about a vertical axis when it is already rotating around the axis that allows it to roll along tangentially. I think you can see the toy car affected by this and turn slightly left

Nice demo. The 7:2 explanation particularly good.

Nett hier, aber waren sie schon mal in Baden-Württemberg

Sounds like a way to understand precession and LaGrange Points. There's something deep about gravity and dynamics in this demo, but I can't quite crystalize it. Any ideas about that, Steve?

I had an amazing realisation about this and have a completely new way of looking at it! This situation is perfectly analogous to the case of cyclotron motion in a magnetic field. The rotating tabletop takes the place of the vector potential and would yield an analogous vertical magnetic field. The ball then is like a charged particle.

04:00 I don't know about all these vectors, but the behaviour still makes perfect sense. As you say, the ball initially stays in place because there is an equilibrium between the speed of the balls rotation and the speed of the discs rotation (at that point/distance from the centre of the disc) Nudging the ball, and pushing it to a lower speed of rotation (closer to the centre of the disc) causes the ball to accelerate forward in a straight line (relative to the disc), because the ball still has its own speed of rotation, which is now faster than the discs at the point closer to the centre of the disc. But because it accelerates forward in a straight line, it forces itself back outward away from the centre of the disc, to a point where the speed of the disc is now faster than the balls rotation. As the ball reaches the outer edges of the disc where the balls rotation relative to the discs rotation is slower, then the discs rotation starts to push back against the balls outward acceleration. But obviously these 2 countering aspects are happening simultaneously. If the mini orbit of the ball were to be drawn, and dissected, so that the line of dissection is perpendicular to discs radius, then the inner portion of the mini orbit, (that half which is closer to the discs centre) would represent the half of the mini orbit where the balls rotation exceeds the discs rotational speed. The other half, would naturally represent the half where the discs rotation exceeds the balls rotational speed. If one were to leave the ball and not nudge it, I believe that after a very very long time, it would eventually fly off the table too.

Did you make or buy that motorized turntable? Just typing in turntable gives the DJ turntables and I would love to have one for my classroom. Awesome videos. I embed many them as supplemental videos to watch for high school physics.

@yeti9634

Жыл бұрын

He is using a pottery wheel. Check with the art department?

@SerifSansSerif

Жыл бұрын

yeah, that's totally a potter's wheel...

@forestschoenrock3040

Жыл бұрын

Lol

Loved the emphasis on intuition in this video. Don't think the lesson/insight could have been taught better 👍

I though I've seen it all. More surprising than anything else in this video is the fact that I just witnessed a sponsor spot about my state in a Steve Mould video. I did NOT see that coming haha

from 3:08 to 3:29 you can actually learn something about cameras as well, where each frame is taken from the top to the bottom, so the bottom of the image is slightly later than the top. This makes it look like the perfectly straight line on the turn table is curved, since it has had more time to rotate the further down it gets. You can also see that when it rotates close to being horizontal this curve goes away since the horizontal lines are taken a lot closer together chronologically.

I'm glad to have found you... purely because your videos make me remember my curiosity as a kid. The things you lose when life takes over! Great going!!

I have always found spinning things and reference frames fascinating, and as an English teacher, I find it fascinating that these very real forces are referred to as fictitious forces and pseudo forces and imaginary forces. I suppose it is to separate them from contact forces and EM forces, but it does seem odd to me. I read that even gravity is a fictitious force. If there's one thing we can be certain of, it's the force sticking our bodies to the floor. Very interesting video and very clearly explained. Thanks.

@HouD

Жыл бұрын

Fictitious forces are not real forces. They do not actually exist like any of the fundamental forces (e.g. electromagnetic or gravitational), but they are very much necessary in order for someone in a non-inertial (i.e. accelerating) reference frame to explain what they are experiencing. As an example: you are a passenger in a remote-controlled car that is moving at a constant speed in a straight line. The car has no windows and has absolutely perfect wheels, shock absorbers, etc. such that you cannot even tell you are moving. Unfortunately, you are also not wearing your seatbelt. All of a sudden, someone turns the wheels sharply to the right via remote control. You will go flying into the left side of the car. From your perspective inside of the vehicle, you have no way of knowing that someone has caused your car to turn. From your perspective, there was suddenly a violent force pulling you into the side of the vehicle. What force has caused this experience for you? In reality, there was none, however from your perspective it must have been so, and so we would attribute (from your perspective) a fictitious force called the centrifugal force. Hope this helps!

@MrSkypelessons

Жыл бұрын

@@HouD I do appreciate the answer, but try saying 'in reality, there was NO force' to someone who was badly injured or even killed by such a force. Surely there was such a force, and not just from his perspective - from our perspective too. And why have I read that gravity is also 'a fictitious force'? Is it because relativity claims (and I certainly can't understand the logic) that gravity is just a curvature of space and time? I have no idea!

@empathogen75

Жыл бұрын

The difference between fundamental and fictitious forces is that if you change your perspective on a fictitious force, you can make it go away (in the sense that they’re no longer terms in any equation), and things like electromagnetism will exist in every reference frame. From an English major point of view - picture something like Fight Club. Tyler Durden was very real for some of the characters’ perspectives and even produced real outcomes for them, but was still not real.

@HouD

Жыл бұрын

@@MrSkypelessons don't conflate the force that might injure someone (e.g. the contact force as they slam into the door of the car) with the perceived force that attracted them towards the door in the first place. We would not label gravity as a fictitious force. However, yes, in a very thereotical sense gravity is not a force like a push or a pull. However this has to do with General Relativity and advanced ideas in physics. For your (and my) every day life experiences, gravity is very much a force that pulls massive object towards one another.

@MrSkypelessons

Жыл бұрын

@@HouD 'We would not label gravity as a fictitious force' - who is we? 'This led Albert Einstein to wonder whether gravity was a fictitious force as well. He noted that a freefalling observer in a closed box would not be able to detect the force of gravity; hence, freefalling reference frames are equivalent to an inertial reference frame (the equivalence principle). Following up on this insight, Einstein formulated a theory with gravity as a fictitious force and attributed the apparent acceleration of gravity to the curvature of spacetime. This idea underlies Einstein's theory of general relativity.'

its because the ball has a 360 degree pivotal axis so it can spin at an angle close to the force applied. its sort of like putting a wheel on a treadmill depending on the friction the wheel could just spin and stay in place. the wheel can only spin around "one" degree of rotation but you throw in a ball that can alter its axis and degree of rotation 360 degrees the ball can pivot, roll, or spin close to the angle of the applied force. a ball is perfect for an object that has a variable axis degree or pivot point. (all of that to say the ball can spin in any direction so if its on a turntable it can spin with it and stay on)

Learning so much today! Actually, earlier on I also learned that Gerbils sneeze for an hour and be sick after eating just a tiny piece of polo mint, thankfully my little Ruperts ok now though. Good video

Love this one. Glad you mentioned the Coriolis effect. When you showed the gyroscope, I thought you were going to talk about procession. That would be a good concept introduce here too. By the way, your videos are great! Adam

@qovro

Жыл бұрын

You've got me visualizing a parade of gyroscopes dressed in fancy costumes.

it would be interesting to see the motion of the ball from a relative point of view with a 360 camera mounted in the centre of the turn table.

So what happens if you tried using a ball with an offset center? Like a bolwing ball (not suggesting trying a bowling ball but something smaller with an offset center perhaps a custom resin ball with an offset cast steel ball bearing inside)

I consider myself a person of curiosity, yet marvel in envy for how much more curious some people are than me. A curious mind is so beautiful

As a 2,055 year old Carpenter it amazes me that after all these years, we still love playing with balls!

@jcf7401

11 ай бұрын

This is beautiful. Thanks for sharing

Gyroscope behavior as an analog to balls on a turntable is a really cool example of symmetries in physics :D (or at least perceived symmetries, but even those are helpful in advancing our knowledge).

They have a turntable for doing these experiments on , and discs and tubes and balls in the Life Science Centre in Newcastle. Played on it a few times. Good to see the mathematics behind it.

amazing! perfect blend of well delivered info-tainment! didnt know what I didnt know.....yknow?

I believe without doubt that there is that fixed ratio because the other factors cancel out, but that being a different constant for hollow balls is really weird. At first glance, it makes sense, but what if you consider the thickness of the ball "shell" as a fraction of its radius? Now you cannot discretely differentiate between whether a ball is hollow or not (or rather, solid balls become a special case of hollow ones), because at the limit→1 they are basically the same

@Geerice

Жыл бұрын

if I'm understanding your comment right, basically the ratio for that hollow ball isn't exact. The ratio is for a theoretical ball with infinitely thin walls. A more complex equation exists for a solid ball with a cavity.

@jameskerns717

Жыл бұрын

As you change the distribution of the mass by hollowing out the middle you make a gradual transformation from solid to a "thin shell". Of course, where do you draw the line at "thin"? When the assumption of a "thin" shell is good enough.

There's this very hands on science museum in the SF bay area called the Exploratorium, my favorite museum as both a kid and an adult. They had an exhibit about this which was my favorite thing there. It was a giant turntable, like 4 feet-ish in diameter and a ton of discs and balls of different weights and sizes and some of the discs had holes in different orientations. I could easily spend my entire day there just playing around with the physics of it, trying so hard to get one to stay on for as long as possible.

@DavidLindes

Жыл бұрын

was going to mention exactly this, but you beat me to it. :) I've spent lots of time there, too... they also have little sticks that one can slide through the holes in some of the discs, or also some rings, to allow them to be held still to set up. Another fun thing is rolling something onto the turntable from the side, as the turntable is basically an inlay on a larger table surface, and the heights are flush to each other... so you can roll a ball on at different angles, and see what it does as it transfers from the static table surface to the dynamic turntable surface. Much fun! Highly recommended to anyone in/around (or visiting) SF.

@JimC

Жыл бұрын

I lived near SF from around 1980 to 1991. That was when the Exploratorium was still in the Palace of Fine Arts. I became a member and visited often. This exhibit was originally intended to show how something on the turntable would be flung off tangentially to it, not straight from the center. But the objects were small disks, and everyone found seeing them roll on the turntable was much more interesting. Getting pennies to roll was fun, too. I don't remember the museum having spheres of any kind for the turntable. I never thought of bringing a ping-pong ball. The most interesting object I saw there was one of those rubber feet for folding chairs or canes. It's shaped like a cone with some of the pointy end cut off, and the bottom was somewhat rounded. A rubber sink/bathtub plug could've be interesting to watch, too.

@playr4

Жыл бұрын

@@JimC Aw I miss that location. It was so much more open than it's current place. You walk through the doors and just as far as you can see there were experiments and things to play with. It's a lot more moderny now, which is fine but it did lose that sense of awe it used to have. I used to go to summer camp there when I was a kid and we would have an hour before it opened with all the exhibits turned on to play around with. Easily the best summer camp experience I can remember.

@JimC

Жыл бұрын

@@playr4 Sounds like lots of fun! In Chicago, back in the 60s, when I was around 11, my older brother worked on Saturdays in the Museum of Science and Industry for a time. He worked in the Swift exhibit (hatching chicks, tending a sheep or two and a few baby pigs). I'd usually go with him (if I didn't oversleep :) ). I couldn't go into the museum proper until opening time. But then I'd hightail it to exhibits that were usually crowded later in the day and wander around until closing. I loved it! The Museum has changed a *lot* since then, but if you're ever in Chicago go see it!

@DavidLindes

Жыл бұрын

@@JimC interesting about the intent. I don't recall what their signage says on it these days, but I know they've had billiard balls among the other options. The rubber feet sound interesting!

could you use this setup to experimentally calculate the moment of inertia of a spinny thing with an awkward shape?

It would be interesting if you tried the same experiment but with a fabric turntable, to potentially give some cheap insight into how the fabric of spacetime may behave in this spheres in a whirlpool scenario.