In my head, I was already constructing a complicated device to spin it with a smaller radius at the top. Then Steve just turns the screwdriver upside down. Now i feel stupid 😁
that is a pretty fair explanation, and the most obvious one. specially because it does happen with other things. its damn mindblowing that its actually gravity and not the radius of the spin that makes it move.
The only think I can think of (haven’t heard their explanation yet) is that magnetic fields have a flow, I think it’s clockwise, that they are acting in. It’s the same reason railguns work, you wind your electromagnets in a way where both magnetic rails have a flow that goes forward towards the tip, and the ammunition is launched that direction. Here, the forces aren’t as extreme, and the magnets don’t have anything to suspend them in open space, so friction stops them from moving, but by spinning it, you’re adding another velocity than just towards the rod, and the magnetic field’s flow makes them roll forward. My thought starts crumbling there though. Dunno if it’s friction that lets it go up, I’m just thinking that the magnets roll and maybe this is why. Edit: well shit I was waaaay off.
No Thank You I disagree. Steve Mould is an amazing science guy on UA-cam and this is called a collaboration. For main content, you should watch Veritasium not 2Veritasium. However, I do agree that he doesn't seem to give two shits about his content or scheduling these days, just posts when he wants to
4 seconds into video... "uhm... centrifugal force? How is that not obvious?" 1:00 into the video... "oh... okay... never mind then..." 5:30 "Ooooh! Because gravity! Okay."
My thoughts exactly. My guess is that the square magnets won't remain "flat", they will reorient to be diamonds, then process up the screwdriver by the same means on the now-angled side. I have 130 square magnets here...I could test it now...but I would have to unpack a bunch of the magnets and that's a PITA. I'll just wait and see what Benjamin has to say Monday. ;)
But in order to be certain this theory is correct, it needs to be tested with different variables. For example, magnets with a square cross section instead of a circle, or a change in relative size in either the metal pole (screwdriver) or the magnets to test the "roll and slip" idea.
Well, since there's no symmetry and gravity always biases it upwards... And as it moves around the screw driver, gravity is tipping the magnet roll downwards, only the bottom edge makes good contact and the strip rolls around its end. And it'll have a turning radius pointing upwards, since the "inside" of the turn is always pointing up thanks to gravity. Kind of like if you take a core of a toilet paper roll or any other cylinder, stand it up on its end on a flat surface and apply a fake "gravity" to the top, tangential to the flat surface thereby tilting the cylinder... If you then push the cylinder along such that it rolls on the remaining edge, it'll tend to translate on the surface away from the direction "gravity" is pointing in. That was my thought anyway, before you pointed out the noise -- though I still think it would work just as well even if it could not slip.
Isn't it general relativity and quantum mechanics that don't get along? I'm pretty sure QFT and even the Dirac Equation are perfectly happy with special relativity...
As soon as I heard him say that, I hit ctrl+f "special" to see if anybody had commented on it. It's inconsistent with general relativity, but Feynman made special relativity work with quantum mechanics.
Quantum Field Theory (QFT) is the unification of special relativity and quantum mechanics. The real challenge is unifying QFT with _general_ relativity.
Wow! I was expecting this to be a fairly lame video boiling down to the tilt of the screwdriver, but I WTFed when he did it upside-down. The stick-slip explanation is gorgeous and unexpected. This video makes me want a new adjective meaning "seemingly lame at first glance but surprisingly interesting." :)
Throughout the video, everything I came up with a counter point he almost immediately explained it to my satisfaction. Cool video, thank you. It's always a good day when I can learn something new.
To prove this theory about gravity's role in this mystery, we should recreate it on the International Space Station where the impact of gravity is minimal. Reminds me of the feather and hammer experiment on the moon...
So for some reason the right channel/side has no audio for your voice during the introduction... Just FYI. Updated: @ 6:17 it's the same. Apparently either your mic was/is 'jacked' (pun intended) or maybe just some slight technical difficulties.... Again - Just wanted you to know, because I'm certain your going to get other comments on this the more the video is watched.
It's a mono mic, he recorded or imported it as stereo, so just the left channel got a signal. Happens quite a lot somehow. You'd think people would watch their videos before uploading them...
I am actually watching with one broaken earphone so in the part where derek is talking there is almost no audio, there is definately some audio though like Jack Evans said
My first guess was what he said we thought was happening, once he he showed us that it wasn’t the way he was turning the screwdriver, I thought that the magnet could be spinning , and it just roles up the screwdriver but I had no idea why. Great explanation. But why wouldn’t the magnet rotate the other way around the pressure point, resulting in it becoming on the upper side of the magnet, and make go down?
The momentum of the magnet and the fact that the lowest point of contact is always under the center of gravity of the magnet creates a torque thatwill make it rise, which ever way is up !
Jason Karim If this were a problem of just geometry, then yes. But I don't know it would fit in 6 seconds with all the forces and points of contact taken into account.
It's a shorter route for the magnet to rotate up than down. Plus, rotating down would mean the magnet would temporarily go further away from the pole, and it doesn't want to do that.
Eddy currents are also in play in, enforcing the direction of rotation, as the opposite way would fight the eddy currents generating from the rod rotation. You can halt the magnets from pirouetting around the pole, yet the magnets will still rise :)
Now we need someone in the ISS to do this experiment. Logic tells the magnets will just spin around. Probably will move up or down depending on little "vertical" movements if done by hand, since it's rather impossible to keep all axis fixed when done by a human hand.
You should have posted this to your main channel. This is a very simple yet very well done video. You could've given Steve far more visibility like that!
That strobe effect shot made me wonder... if, rather than spinning the magnets around the pole, you spin the pole and either prevent - or allow - the magnets to spin with it, would they still climb? Great explanation, by the way! I’ve also visited and subscribed to Steve Mould’s channel and now I know I’m not going to get anything done today!!
azdgariarada What are you talking about? Spinning the tether would make it *more* stable, in fact that's how some of the first satellites were launched. en.wikipedia.org/wiki/Spin-stabilisation
Very good explanation! I first thought it was the thing he disproved at the very beginning. Basic centripetal force if I'm not mistaking. Really nice to have my intuition broken and then rebuilt in a better way :)
Before hearing the explanation, my guess is that it's because of the greater momentum/centrifugal force being at the top, where the swing is the largest. It's being pulled toward the greater force.
But after watching, the rotation and slipping of the magnets does appear to be the best explanation. Now, will square magnets exhibit the same climbing action? I suspect they would. And maybe do to my original hypothesis. Maybe.
Your initial (not original) hypothesis was the one he explained at the beginning of the video and which he quickly showed was false by turning the screwdriver upside down. Did you and the people who liked your comments even watch the video?
i mean, i haven't really seen the video yet but from what he's shown so far im reminded of when i used to do that using a pencil and a ruler and watch it rise from the bottom and go flying off
Oliver Reichenbach If like me they all thought the transition to the second video was going to be the explanation, and were told to make a guess before the explination, then why would you accuse them of not watching the whole video?
Square magnets wont work, but they should straighten themselves when starting at a 45 degree angle (and slightly rise in the process) according to this explanation
Hi all, I'm the OliReading who first came across this strange phenomenon - that's my tweet to Steve Mould you can see 30 seconds into the video. Very pleased it's stimulated so much discussion here, and quite pleased that the solution Steve gives is not a very obvious one! Take a look at my twitter feed @OliReading, and also check out some of my neat magnet art at instagram.com/oligettingcrafty/
Stick-slip. The horrible phenomenon that also causes squeaky hinges, screeching forks on plates, high pitched squealing brakes, stuck drawers and stuck sliding windows.
Lenz's law, change of flux in metal screwdriver hence eddy current in screwdriver which in turn oppose magnetic field of neodymium magnets, causing them to rise.
This can‘t be the reason, because if your argumentation would be true it wouldn‘t rise up in the experiment where he holds the ruler against the magnets. In that experiment there is no change of flux.
Even when there's a scale relative motion existed between magnet and screwdriver. As the point of contact keeps changing there is still a possibility of formation of eddy current. Might be wrong, but it's just a thought.
Gravity MUST play a part, or the chirality of spin and orientation of the screwdriver would matter Instead, we see the magnets always traveling against the force of gravity
Lenz's law states that the emf is induced in such a way, so as to neutralize its cause. According to this if we are rotating clockwise Lenz's law should make rotate counterclockwise. It has nothing to do with up and down.
I’ve been subscribed to Steve Mould for about 18months or so I guess and I love his channel as much as I love yours. Nice to see you supporting other youtubers. But you haven’t replied to my email and it’s been like 2years or so. No problem though. I’ll keep waiting, you must be really busy.
but with already over 14k views you would save more collective time. save 5 minutes 14k times by once spending 50 minutes more would have been a good trade off
It's so easy to explain, that I can't explain it to be understood by you. Outward momentum is bigger at the top because the movement you make is like a cone that's bigger at the top and smaller at the bottom.
A very cool "easter egg" if you will in this video is that you preformed an experiment pointing towards your hypothesis about the phenomena without even mentioning it. You claimed the slipping was what caused the phenomena, meaning this hypothesis predicts that if no slipping occurs the magnets won't move up, and when you put it on a drill and spunn it it did indeed stay in place :)
another cool example of how audio can be used to help solve physics problems. We can hear faster than we can see and there are many problems worth examining with sound along side visuals
My theory right away, 16 seconds in. The metal rod, when spinning, has a slight angle, meaning the inertia from spinning acts like it would on a cone, causing it to not be perpendicular to the surface of the cone, allowing for a torque to push it upwards. Okay, so you're implying I was wrong now. Seeing your experiments, I'm satisfied with being wrong. I'd suggest putting a bright yellow line down one side, getting access to a slow motion camera, and using a stationary pole for rotation. This would be a good test for your theory.
Once he started talking about how it slips, I just started thinking that the magnets were spinning up it, as well. It's handy sometimes to have a natural understanding of how things work. Oh, and I hope you get more rest, Derek. You looked like you hadn't been getting much sleep or were sick when recording this. Best of luck.
The explanation might be incorrect. Look at 5:53, the resulting direction of the rotation of the magnets does not match with the explanation. I think that the pivot point remains the same, but the magnets rotate downwards due to gravity and the resulting momentum, instead of rotating upwards. Then they slip upwards. Micht be wrong, but i think that this explanation is at least not complete... Awesome video still
Steve's explanation seems cogent. This would be a great problem for Physics students, especially M.E. majors, to either confirm or provide an alternative with actual testing with measurements, data collection & analysis to support either hypothesis. This physics (mechanics) problem is very nuanced, but roughly comparable to an existing mechanism called a 'helical roller lead screw assembly'. The mechanical couple that Steve describes as having skip-slip dynamics means that the sound is a clue to the average frequency of that repetitive action; engineers call that 'creep'. This type of creep results from rollers making contact with each other along a path angled from the tangent of contact, requiring tiny periodic twists. In this experiment, the path of rolling contact would likely be a smooth helix around the screwdriver shaft, but with the helical pitch changing as the twirling speed changes, and/or magnets are added or subtracted. Students would be required to model this problem to accommodate all the significant variables well enough to make predictions. Since this is weird, and has little prior art, it's not a problem that students could simply look up on the Internet for solutions. Physics instructors and professors could have fun with this one!
I really think that the real answer has to do with electric/magnetic fields. I heard that when you spin one, it creates another, or something of that style, so the magnet would feel attracted by the top
Some tests that can be done: * Try with square magnets * Draw a line on the stack of magnets with marker and film in slow motion to see if it's rotating. * Go on that weightless plane ride with parabolic dives and test it there * File a deep groove in the magnet that touches the screwdriver so that it has two contact points and no slip * Attach a piece of string from the outer end of the magnet stack to the tip of the screwdriver to counteract or even overcome the force of gravity (that would be pretty hard to get just right * Hold the screwdriver horizontal (parallel to the ground) and spin it
I conveniently just finished rewatching Walter Lewin’s lecture around angular momentum. I’m sure you remember it. I imagine the same principles apply here? Ah, I just finished watching. Lol! I love counter intuitive puzzles. Thanks for sharing!
Well the explanation is far simpler than what I had imagined. I was thinking of something long the lines of electromagnetic induction (moving magnet + wire = current, current + changing magnet field = force, although thinking about that now it'd probably cancel itself out).
Hi Derek! I don’t think that explanation has anything to do with what is actually happening. I think it has to do with centrifugal force: If you put the circle of your keys on a pencil and start spinning it, the keys will move up exactly like the magnets in this video until they get out of the pencil. And if I’m not wrong, that’s because of centrifugal force, that when an object spins moves away from it’s axis and that makes it go up until it is 90° from the axis, but since the pencil, the screw driver and even the drill doesn’t spin in a perfect way, that will make the object go up. Maybe I’m wrong but seams more logical to me.
That's a nice puzzle. Not so easy that you can work it out in your head instantly and not so hard that you can't understand the explanation. Also a cool conversation starter when you have friends over.
waaahoooo!!! just randomly looked at the notifications and found veritasium...slo mo guys..and sixty symbols.....if u ask me these videos made my day........
Stopping at 2:06 to record my guess. Gravity pulls down on the whole stack, making the point closest to the rod a “u” shape, so no matter which direction it rolls, the next point on the magnet cylinder to touch the rod will always be slightly higher than the section that was previously in contact. This compounds over multiple rotations, helped along by the inertia of the previous upward push, making subsequent rises easier and easier.
Gravity acting on the magnets pulls the end of the magnets down. That puts the magnets at an angle different to 90degrees. That angle causes resistance on the lower side and no resistance on the top. That lack of resistance drags the magnets up the shaft. Hope that makes sense
Wonder why the hula hoop on my sexy neighbors body goes up the faster she twists, whereas the hoop falls down immediately when i try the same . The answer is, she has highly magnetic personality, just like the neodymium magnets in your video. She attracts all the vermin in the lane. LOL
After watching less than half a minute of this, here is my explanation: When you move the screwdriver around a bit in an effort to get the magnets to spin around, you are moving it quickly in very small partial rotations. These short arcs, while not full 360-degree rotations, nonetheless impart a force on the magnets that is similar to the force that keeps the Earth from falling into the sun due to the Sun's gravity. Any body in a rotational motion, even if it is a small arc that is only a portion of a full rotation, will have a tendency to move outward and away from the center of rotation. This is just like spinning a yoyo on the end of its string. The yoyo has a tendency to fly away, but the string keeps it attached, so it doesn't. The main point I want to make here is that the magnets naturally tend to fly away off of the screwdriver because of the small arcs in the motion of the screwdriver that is used to spin the magnets around. Basically, the screwdriver is making at least two different types of motion. One is back and forth, which is what causes the magnets to rotate around the center of the shaft of the screw driver. However, the other is the small arcs that also get the magnets to move in a direction perpendicular to their spinning. While I probably haven't explained this as well as I could have, the small arcs would have their center either at or near the fingertips (I think you know what I mean) or at the back of the handle end the screwdriver. Because the motion is erratic, that center is probably moving around a lot. You could probably test this idea by putting washers on the screwdriver that are nonmagnetic. Doing the same thing would probably cause the washers to start to move towards the end of the screwdriver opposite the handle and where the hand is holding it. Anyway, that's my explanation. Do you like it? What do you think?
Okay: I watched the rest of the video, so now I've watched the whole video all the way through, and I must say I did not expect the explanation that came. Also, when the presenter turned the screwdriver upside down, and the magnets continued to go upwards, that was pretty interesting. In conclusion, perhaps my explanation was not the complete answer in the case where the magnets were going away from the hand.
First thought: The magnets are being pulled down by gravity, but stuck to the screw driver (obviously). Though this puts more friction on the bottom of the round magnet. As you twirl it around, that causes it to roll. Though I'm unsure if it's the disproportionate friction at the bottom acting like a weak friction ratchet to make it trend upwards, or perhaps the disproportionate friction makes it roll a little around the axis of the magnet, which would make it want to push upwards, since that's where the friction... (yeah, he's going over it right now in the video at 5:30... wohoo, I was right!?)
The Left Hand Rule :) The magnets movement induces a current through the screwdriver, and an external magnetic field (also the magnet) is applied across that flow, the screwdriver experiences a force perpendicular both to that field and to the direction of the current flow (i.e they are mutually perpendicular) . A left hand can be held, like a gun with the index finger pointing and the thumb is up, so as to represent three mutually orthogonal axes on the thumb, fore finger and middle finger. Each finger is then assigned to a quantity (mechanical force, magnetic field and electric current). The right and left hand are used for generators and motors respectively.
I also suspect the same principle that a drill works on whatever that motion is called, it draws the magnets up somehow in the same way that a corkscrew does but uses magnetic forces instead. With both the rotating actions at work it also would be interesting to see theorize is this would be practical for a high rise elevators or even possibly to space.
If it was the slip and push making the magnets go up, why does it still go up when it wasn't rotating around the screwdriver (when he put a ruler on the side)?
In order to move around the shaft the magnets actually rotate. Since the weight of the magnet is a lever the bottom lip will have the most friction and drive the rotation. Due to the circular magnets and pole the frictional forces will have an upwards component
My left ear enjoyed the start
I was thinking the same.
And the end.
My right one didn't
Yeah me too
Sounds like the microphone was broken, and the audio was not looked at
ME "Well that's easy to answer..."
Steve "If you turn upside down, it still goes up"
ME "Alright... I still a dumb mf"
In my head, I was already constructing a complicated device to spin it with a smaller radius at the top. Then Steve just turns the screwdriver upside down. Now i feel stupid 😁
Paul Paulson haha, same here. I am sure we would have come to that conclusion briefly though lol.
Guess I am joining your club...it was obvious...and also wrong!
I was thinking the same exact thing. You weren't the only one.
that is a pretty fair explanation, and the most obvious one. specially because it does happen with other things. its damn mindblowing that its actually gravity and not the radius of the spin that makes it move.
Occam's Razor, you betray us once more
Why is this on 2veritasium and not on the main channel?
Steve Mould is High quality content!
Exactly, if you want to get people to check out Steve's channel then show this to 4.6 mil people rather than just .5 mil.
@@robinsparrow1618 5 mil. am i missing something here?
@@TheSmith645 .5 mil
half a million
4.6 is bigger than .5
@@robinsparrow1618 damn i missed the dot before 5
@@TheSmith645 all good
The only think I can think of (haven’t heard their explanation yet) is that magnetic fields have a flow, I think it’s clockwise, that they are acting in. It’s the same reason railguns work, you wind your electromagnets in a way where both magnetic rails have a flow that goes forward towards the tip, and the ammunition is launched that direction. Here, the forces aren’t as extreme, and the magnets don’t have anything to suspend them in open space, so friction stops them from moving, but by spinning it, you’re adding another velocity than just towards the rod, and the magnetic field’s flow makes them roll forward. My thought starts crumbling there though. Dunno if it’s friction that lets it go up, I’m just thinking that the magnets roll and maybe this is why.
Edit: well shit I was waaaay off.
Marvel: "Avengers Infinity War is the most ambitious crossover event in history"
Veritasium: "hold my beer."
Haha wow I thought exactly the same thing when I saw the title XD
Added Kina we're memers at heart, memers for life
I was literally watching Infinity War videos when I saw this in my Sub.
No Thank You I disagree. Steve Mould is an amazing science guy on UA-cam and this is called a collaboration. For main content, you should watch Veritasium not 2Veritasium. However, I do agree that he doesn't seem to give two shits about his content or scheduling these days, just posts when he wants to
It's like Magneto teaming up with Iron Man.
4 seconds into video... "uhm... centrifugal force? How is that not obvious?"
1:00 into the video... "oh... okay... never mind then..."
5:30 "Ooooh! Because gravity! Okay."
Same. I always thought it was centrifugal force.
I am amazed to be wrong about something so simple.
I thought it was Eddy currents (the same thing that happens when you drop a neodymium magnet through a foil tube or copper pipe)
What if the magnets are square?
I'll test that on monday, I ordered 12mm cubic magnets. If the video is correct, I shouldn't observe the effect !
My thoughts exactly. My guess is that the square magnets won't remain "flat", they will reorient to be diamonds, then process up the screwdriver by the same means on the now-angled side.
I have 130 square magnets here...I could test it now...but I would have to unpack a bunch of the magnets and that's a PITA. I'll just wait and see what Benjamin has to say Monday. ;)
Just leaving this here to get reminded once u answer.
same here
@Benjamin and while you're at it, spin it clockwise and anti-clockwise to check if the created electric field has something to do with it
But in order to be certain this theory is correct, it needs to be tested with different variables. For example, magnets with a square cross section instead of a circle, or a change in relative size in either the metal pole (screwdriver) or the magnets to test the "roll and slip" idea.
Well, since there's no symmetry and gravity always biases it upwards... And as it moves around the screw driver, gravity is tipping the magnet roll downwards, only the bottom edge makes good contact and the strip rolls around its end. And it'll have a turning radius pointing upwards, since the "inside" of the turn is always pointing up thanks to gravity. Kind of like if you take a core of a toilet paper roll or any other cylinder, stand it up on its end on a flat surface and apply a fake "gravity" to the top, tangential to the flat surface thereby tilting the cylinder... If you then push the cylinder along such that it rolls on the remaining edge, it'll tend to translate on the surface away from the direction "gravity" is pointing in.
That was my thought anyway, before you pointed out the noise -- though I still think it would work just as well even if it could not slip.
Someone please explain what on earth I just read.
It's still just increasing centrifugal force to the top. The magnets hang to the ground, creating a upward 'track' on the axis.
You can demonstrate it by drawing a line with a marker over the magnets and do a short spin to check it it rotated the way you predicted.
Isn't it general relativity and quantum mechanics that don't get along? I'm pretty sure QFT and even the Dirac Equation are perfectly happy with special relativity...
Yeah, at 6:05 he says general relativity, the first time was probably a stick and slip of the tongue ! :P
yes qft = qm + sr basically, its gravity thats the problem, im sure steve knows this prob just a hiccup he didnt catch
As soon as I heard him say that, I hit ctrl+f "special" to see if anybody had commented on it. It's inconsistent with general relativity, but Feynman made special relativity work with quantum mechanics.
I was wondering that myself!
Quantum Field Theory (QFT) is the unification of special relativity and quantum mechanics.
The real challenge is unifying QFT with _general_ relativity.
Such an exciting collaboration! And really intuitively explained too- well done ☺️
I love Steve so much. He explains everything so nicely and elegantly that even a 5 year old would understand after a while.
what a fantastically calming way of speaking
Wow! I was expecting this to be a fairly lame video boiling down to the tilt of the screwdriver, but I WTFed when he did it upside-down. The stick-slip explanation is gorgeous and unexpected.
This video makes me want a new adjective meaning "seemingly lame at first glance but surprisingly interesting." :)
I think he should of tried to prove his hypothesis by using square magnets
I would be curious to see if the same affect is observed with a length of all-thread rod.
Steve Mould has the best science channel on UA-cam. I love the way he explains things
Yep, Steve Mould definitely deserves more subscribers!
should've painted the magnets on the sides and made another demo that way.
yes, chequermarked magnets and a high speed camera ought to be able to verify this
i miss you derek
Are you a former lover of his?
Dirk from Veritablium
I miss you dalek
GAYYYYYYYYYY
He is at his thirties, he found more perspective things to do.
But yes, his videos are ones of the best on youtube.
Throughout the video, everything I came up with a counter point he almost immediately explained it to my satisfaction. Cool video, thank you. It's always a good day when I can learn something new.
FFS I rly thought my headset was broken or smth bcause of the start, you scared the shit out of me, I just bought it a few weeks ago
My headset IS broken, so I couldn't even hear him lmao
WoyablePitt Your keyboard seems broken though, there are letters missing in some of the words...
You think that’s bad?
I was listening on my phone, I thought it had blown the speaker or something... -_-
WoyablePit
Steve is really awesome. He has the most easy to understand explanations Ive seen.
To prove this theory about gravity's role in this mystery, we should recreate it on the International Space Station where the impact of gravity is minimal. Reminds me of the feather and hammer experiment on the moon...
You could just hold the screwdriver horizontal so their is no top or bottom quicker and cheaper.
I recommend 1.25 speed for easier viewing :) great video! It's satisfying to get such a nice explanation for a beautiful little phenomenon like that.
when I started watching this video, I was like, "It's so obvious", but then you turned it upside down .-.
Almost wrecked my headphones trying to correct the missing audio channel on Derek, but then Steve came one. Thanks Steve!
So for some reason the right channel/side has no audio for your voice during the introduction... Just FYI.
Updated: @ 6:17 it's the same. Apparently either your mic was/is 'jacked' (pun intended) or maybe just some slight technical difficulties....
Again - Just wanted you to know, because I'm certain your going to get other comments on this the more the video is watched.
It's a mono mic, he recorded or imported it as stereo, so just the left channel got a signal. Happens quite a lot somehow. You'd think people would watch their videos before uploading them...
There is actually some sound on the right channel it's just really quiet. Also yeah, this keeps happening and it's quite annoying.
I am actually watching with one broaken earphone so in the part where derek is talking there is almost no audio, there is definately some audio though like Jack Evans said
Yeah, but it was still really quiet... had to turn the volume all the way up to be able to hear him on the right side.
Now if only there were prizes of millions of dollars for people who solve mini mysteries.
My first guess was what he said we thought was happening, once he he showed us that it wasn’t the way he was turning the screwdriver, I thought that the magnet could be spinning , and it just roles up the screwdriver but I had no idea why. Great explanation.
But why wouldn’t the magnet rotate the other way around the pressure point, resulting in it becoming on the upper side of the magnet, and make go down?
The momentum of the magnet and the fact that the lowest point of contact is always under the center of gravity of the magnet creates a torque thatwill make it rise, which ever way is up !
Benjamin Herisson oh right, thanks for the explanation.
Jason Karim If this were a problem of just geometry, then yes. But I don't know it would fit in 6 seconds with all the forces and points of contact taken into account.
It's a shorter route for the magnet to rotate up than down. Plus, rotating down would mean the magnet would temporarily go further away from the pole, and it doesn't want to do that.
Eddy currents are also in play in, enforcing the direction of rotation, as the opposite way would fight the eddy currents generating from the rod rotation. You can halt the magnets from pirouetting around the pole, yet the magnets will still rise :)
Now we need someone in the ISS to do this experiment. Logic tells the magnets will just spin around. Probably will move up or down depending on little "vertical" movements if done by hand, since it's rather impossible to keep all axis fixed when done by a human hand.
why didn't he prove his explanation by using square magnets ??
*Puts it sideways.
*Magnet flies to space.
So if we do the same experiment on the ISS (where there is no gravity) magnets don't "climb" on the stick. Correct?
Gino Giotto they should not, no,
Just a correction, there is gravity on ISS, but it's just constantly falling as it revolves around earth. It's a microgravity environment.
...or just hold the screwdriver sideways.
You should have posted this to your main channel. This is a very simple yet very well done video. You could've given Steve far more visibility like that!
Steve could have proved this hypothesis by spinning the magnets around a horizontal screwdriver. The result being they move in neither direction.
if the screwdriver stayed level, it shouldn't move at all
Really like Steve Mould's videos. Been following him for a while. Well worth a sub!
To prove your theory, I think you should make same experiment with rectangular cuboid magnet.
That strobe effect shot made me wonder... if, rather than spinning the magnets around the pole, you spin the pole and either prevent - or allow - the magnets to spin with it, would they still climb? Great explanation, by the way! I’ve also visited and subscribed to Steve Mould’s channel and now I know I’m not going to get anything done today!!
Suddenly very aware of Derek's mortality. Looks like he's aged 15 years since his last upload
because it was 15 years ago
As soon as he mentioned the pressure at the contact points, my brain lit up like a solar flare.
Now build one space elevator using that :3
Yes!
lmao genius
I like the idea, but how would you get down? Also, wouldn't it take a ridiculous amount of energy to spin something that massive?
Horrible idea.
"yeah, let's introduce a destabilizing oscillation effect into a 35,000 km orbital tether" What could go wrong?
azdgariarada What are you talking about? Spinning the tether would make it *more* stable, in fact that's how some of the first satellites were launched. en.wikipedia.org/wiki/Spin-stabilisation
I got the idea that the weight was bearing more on the bottom than the top, but didn't know where to go from there. Good video.
To be played at 1.25x
wwwKx 1.5x
Saved my day
Thank you
Those are rookie numbers.
Too perfect with 1.25x
Wow wow wow... Excellent explanation. My mind was blown away. THIS is called a scientific study
S T I C C AND S L I P P
Very good explanation!
I first thought it was the thing he disproved at the very beginning. Basic centripetal force if I'm not mistaking.
Really nice to have my intuition broken and then rebuilt in a better way :)
Before hearing the explanation, my guess is that it's because of the greater momentum/centrifugal force being at the top, where the swing is the largest. It's being pulled toward the greater force.
But after watching, the rotation and slipping of the magnets does appear to be the best explanation. Now, will square magnets exhibit the same climbing action? I suspect they would. And maybe do to my original hypothesis. Maybe.
Your initial (not original) hypothesis was the one he explained at the beginning of the video and which he quickly showed was false by turning the screwdriver upside down. Did you and the people who liked your comments even watch the video?
i mean, i haven't really seen the video yet but from what he's shown so far im reminded of when i used to do that using a pencil and a ruler and watch it rise from the bottom and go flying off
Oliver Reichenbach If like me they all thought the transition to the second video was going to be the explanation, and were told to make a guess before the explination, then why would you accuse them of not watching the whole video?
Square magnets wont work, but they should straighten themselves when starting at a 45 degree angle (and slightly rise in the process) according to this explanation
Hi all, I'm the OliReading who first came across this strange phenomenon - that's my tweet to Steve Mould you can see 30 seconds into the video. Very pleased it's stimulated so much discussion here, and quite pleased that the solution Steve gives is not a very obvious one!
Take a look at my twitter feed @OliReading, and also check out some of my neat magnet art at instagram.com/oligettingcrafty/
I have no sound at all when you're speaking
Do you only have a left speaker?
I do, but it may be broken ^^
Yes, but it was off (the balance was set to "all right") for an unknown reason ^^
That's funny, this video helped you troubleshoot your pesky speaker issues. V2 FTW
Bastien Durel I think left
Stick-slip. The horrible phenomenon that also causes squeaky hinges, screeching forks on plates, high pitched squealing brakes, stuck drawers and stuck sliding windows.
Lenz's law, change of flux in metal screwdriver hence eddy current in screwdriver which in turn oppose magnetic field of neodymium magnets, causing them to rise.
If what you say is true, it should move downwards if the screw driver is supn the other way
This can‘t be the reason, because if your argumentation would be true it wouldn‘t rise up in the experiment where he holds the ruler against the magnets. In that experiment there is no change of flux.
Even when there's a scale relative motion existed between magnet and screwdriver. As the point of contact keeps changing there is still a possibility of formation of eddy current. Might be wrong, but it's just a thought.
Gravity MUST play a part, or the chirality of spin and orientation of the screwdriver would matter
Instead, we see the magnets always traveling against the force of gravity
Lenz's law states that the emf is induced in such a way, so as to neutralize its cause. According to this if we are rotating clockwise Lenz's law should make rotate counterclockwise. It has nothing to do with up and down.
That was a very good explanation, having those models really made it clear what was going on. Great video!
Hmm haven't we all tried this with a pencil and some kind of ring when we were little? But I guess putting magnets into anything will make it cooler.
Exactly my thoughts! Spinning a ring around a pencil makes it rise up too.
nope it just makes it go away from your hand. If you try spinning it upsite down, it'll just fall
Except those two things have nothing do do with each other and do not even show the same effect.
I’ve been subscribed to Steve Mould for about 18months or so I guess and I love his channel as much as I love yours. Nice to see you supporting other youtubers. But you haven’t replied to my email and it’s been like 2years or so. No problem though. I’ll keep waiting, you must be really busy.
I feel like with the right 3D animation this could've been explained in about 6 seconds instead of six minutes.
but it will take 60 minutes to make instead of 6 minutes XD
chan yoon jun lol
but with already over 14k views you would save more collective time.
save 5 minutes 14k times by once spending 50 minutes more would have been a good trade off
Yeah but I prefer this hands on explanation
More like 600 minutes to make, not 60.
It's so easy to explain, that I can't explain it to be understood by you. Outward momentum is bigger at the top because the movement you make is like a cone that's bigger at the top and smaller at the bottom.
This was discovered by someone who was bored and spun magnets on a screw driver randomly. What a world we live in
So many great discoveries were by accident.
JustKeith I agree!
Just like watching a log roll down a hill and inventing the wheel.
A very cool "easter egg" if you will in this video is that you preformed an experiment pointing towards your hypothesis about the phenomena without even mentioning it. You claimed the slipping was what caused the phenomena, meaning this hypothesis predicts that if no slipping occurs the magnets won't move up, and when you put it on a drill and spunn it it did indeed stay in place :)
You and the team need to pass this one on to the space station for examination in low gravity.
Nice work.
You could just hold the screwdriver horizontal so their is no top or bottom quicker and cheaper.
another cool example of how audio can be used to help solve physics problems. We can hear faster than we can see and there are many problems worth examining with sound along side visuals
My theory right away, 16 seconds in. The metal rod, when spinning, has a slight angle, meaning the inertia from spinning acts like it would on a cone, causing it to not be perpendicular to the surface of the cone, allowing for a torque to push it upwards.
Okay, so you're implying I was wrong now. Seeing your experiments, I'm satisfied with being wrong.
I'd suggest putting a bright yellow line down one side, getting access to a slow motion camera, and using a stationary pole for rotation. This would be a good test for your theory.
Once he started talking about how it slips, I just started thinking that the magnets were spinning up it, as well. It's handy sometimes to have a natural understanding of how things work.
Oh, and I hope you get more rest, Derek. You looked like you hadn't been getting much sleep or were sick when recording this. Best of luck.
I've been subscribed ever since he uploaded the gravity waves video. his content is amazing :D
The explanation might be incorrect.
Look at 5:53, the resulting direction of the rotation of the magnets does not match with the explanation.
I think that the pivot point remains the same, but the magnets rotate downwards due to gravity and the resulting momentum, instead of rotating upwards. Then they slip upwards.
Micht be wrong, but i think that this explanation is at least not complete...
Awesome video still
Steves videos almost always amaze me. This was another great one. Thanks for sharing it with us! :)
Steve Mould should be mentioned on the main channel.
He deserves that, I'm sure!
this topic should be revisited. a WAY to observe whether the magnets are also 'rotating' is NEEDED. cheers
Steve's explanation seems cogent. This would be a great problem for Physics students, especially M.E. majors, to either confirm or provide an alternative with actual testing with measurements, data collection & analysis to support either hypothesis. This physics (mechanics) problem is very nuanced, but roughly comparable to an existing mechanism called a 'helical roller lead screw assembly'. The mechanical couple that Steve describes as having skip-slip dynamics means that the sound is a clue to the average frequency of that repetitive action; engineers call that 'creep'. This type of creep results from rollers making contact with each other along a path angled from the tangent of contact, requiring tiny periodic twists. In this experiment, the path of rolling contact would likely be a smooth helix around the screwdriver shaft, but with the helical pitch changing as the twirling speed changes, and/or magnets are added or subtracted. Students would be required to model this problem to accommodate all the significant variables well enough to make predictions.
Since this is weird, and has little prior art, it's not a problem that students could simply look up on the Internet for solutions. Physics instructors and professors could have fun with this one!
I really think that the real answer has to do with electric/magnetic fields. I heard that when you spin one, it creates another, or something of that style, so the magnet would feel attracted by the top
Fantastic explanation and visual demonstration.
Some tests that can be done:
* Try with square magnets
* Draw a line on the stack of magnets with marker and film in slow motion to see if it's rotating.
* Go on that weightless plane ride with parabolic dives and test it there
* File a deep groove in the magnet that touches the screwdriver so that it has two contact points and no slip
* Attach a piece of string from the outer end of the magnet stack to the tip of the screwdriver to counteract or even overcome the force of gravity (that would be pretty hard to get just right
* Hold the screwdriver horizontal (parallel to the ground) and spin it
I conveniently just finished rewatching Walter Lewin’s lecture around angular momentum. I’m sure you remember it. I imagine the same principles apply here? Ah, I just finished watching. Lol! I love counter intuitive puzzles. Thanks for sharing!
Well the explanation is far simpler than what I had imagined. I was thinking of something long the lines of electromagnetic induction (moving magnet + wire = current, current + changing magnet field = force, although thinking about that now it'd probably cancel itself out).
I could not manage for the life of me to watch this at normal playback speed
What a great video! Very interactive, he was answering my questions rhight after i was aking them.
Hi Derek! I don’t think that explanation has anything to do with what is actually happening. I think it has to do with centrifugal force:
If you put the circle of your keys on a pencil and start spinning it, the keys will move up exactly like the magnets in this video until they get out of the pencil.
And if I’m not wrong, that’s because of centrifugal force, that when an object spins moves away from it’s axis and that makes it go up until it is 90° from the axis, but since the pencil, the screw driver and even the drill doesn’t spin in a perfect way, that will make the object go up.
Maybe I’m wrong but seams more logical to me.
Interesting theory, and one that ought to be simple to test: grease the screwdriver with something and see if the magnets still rise up.
I want to see Tadashi Tokieda solve this problem. He has always the coolest ways to really show and solve the solution.
"PIVOT! PIVOT! PIVOT!! PIVOOOTT!!!"
Great video :D
That's a nice puzzle. Not so easy that you can work it out in your head instantly and not so hard that you can't understand the explanation. Also a cool conversation starter when you have friends over.
Yay, the explanation I set up in the original twitter thread was correct!
Omg wow... I totally thought that it was because of that flinging motion of the spinning. This is actually really amazing haha!
Why is this a second channel video? This feels first channel worthy.
waaahoooo!!! just randomly looked at the notifications and found veritasium...slo mo guys..and sixty symbols.....if u ask me these videos made my day........
It'll be interesting to see them do this experiment on the ISS
You could just hold the screwdriver horizontal so their is no top or bottom quicker and cheaper.
Stopping at 2:06 to record my guess. Gravity pulls down on the whole stack, making the point closest to the rod a “u” shape, so no matter which direction it rolls, the next point on the magnet cylinder to touch the rod will always be slightly higher than the section that was previously in contact. This compounds over multiple rotations, helped along by the inertia of the previous upward push, making subsequent rises easier and easier.
Ooh, not far off.
Gravity acting on the magnets pulls the end of the magnets down. That puts the magnets at an angle different to 90degrees. That angle causes resistance on the lower side and no resistance on the top.
That lack of resistance drags the magnets up the shaft.
Hope that makes sense
Love the giant props 😅
Wonder why the hula hoop on my sexy neighbors body goes up the faster she twists, whereas the hoop falls down immediately when i try the same . The answer is, she has highly magnetic personality, just like the neodymium magnets in your video. She attracts all the vermin in the lane. LOL
After watching less than half a minute of this, here is my explanation: When you move the screwdriver around a bit in an effort to get the magnets to spin around, you are moving it quickly in very small partial rotations. These short arcs, while not full 360-degree rotations, nonetheless impart a force on the magnets that is similar to the force that keeps the Earth from falling into the sun due to the Sun's gravity. Any body in a rotational motion, even if it is a small arc that is only a portion of a full rotation, will have a tendency to move outward and away from the center of rotation. This is just like spinning a yoyo on the end of its string. The yoyo has a tendency to fly away, but the string keeps it attached, so it doesn't. The main point I want to make here is that the magnets naturally tend to fly away off of the screwdriver because of the small arcs in the motion of the screwdriver that is used to spin the magnets around. Basically, the screwdriver is making at least two different types of motion. One is back and forth, which is what causes the magnets to rotate around the center of the shaft of the screw driver. However, the other is the small arcs that also get the magnets to move in a direction perpendicular to their spinning. While I probably haven't explained this as well as I could have, the small arcs would have their center either at or near the fingertips (I think you know what I mean) or at the back of the handle end the screwdriver. Because the motion is erratic, that center is probably moving around a lot. You could probably test this idea by putting washers on the screwdriver that are nonmagnetic. Doing the same thing would probably cause the washers to start to move towards the end of the screwdriver opposite the handle and where the hand is holding it. Anyway, that's my explanation. Do you like it? What do you think?
Okay: I watched the rest of the video, so now I've watched the whole video all the way through, and I must say I did not expect the explanation that came. Also, when the presenter turned the screwdriver upside down, and the magnets continued to go upwards, that was pretty interesting. In conclusion, perhaps my explanation was not the complete answer in the case where the magnets were going away from the hand.
I agree, satisfying explanation! Nice job fellas.
First thought: The magnets are being pulled down by gravity, but stuck to the screw driver (obviously). Though this puts more friction on the bottom of the round magnet. As you twirl it around, that causes it to roll. Though I'm unsure if it's the disproportionate friction at the bottom acting like a weak friction ratchet to make it trend upwards, or perhaps the disproportionate friction makes it roll a little around the axis of the magnet, which would make it want to push upwards, since that's where the friction... (yeah, he's going over it right now in the video at 5:30... wohoo, I was right!?)
Jokes on you, I'm already subscribed. I love both of your content :)
The Left Hand Rule :)
The magnets movement induces a current through the screwdriver, and an external magnetic field (also the magnet) is applied across that flow, the screwdriver experiences a force perpendicular both to that field and to the direction of the current flow (i.e they are mutually perpendicular) . A left hand can be held, like a gun with the index finger pointing and the thumb is up, so as to represent three mutually orthogonal axes on the thumb, fore finger and middle finger. Each finger is then assigned to a quantity (mechanical force, magnetic field and electric current). The right and left hand are used for generators and motors respectively.
I also suspect the same principle that a drill works on whatever that motion is called, it draws the magnets up somehow in the same way that a corkscrew does but uses magnetic forces instead. With both the rotating actions at work it also would be interesting to see theorize is this would be practical for a high rise elevators or even possibly to space.
If it was the slip and push making the magnets go up, why does it still go up when it wasn't rotating around the screwdriver (when he put a ruler on the side)?
Welp, now we need to send a stack of magnets and a screwdriver to the international space station.
In order to move around the shaft the magnets actually rotate. Since the weight of the magnet is a lever the bottom lip will have the most friction and drive the rotation. Due to the circular magnets and pole the frictional forces will have an upwards component