Instructables

How to Build a Magnetic Levitating Top

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Nope, no Photoshop and no fishing line were used to make this picture, just 100% pure physics and some patience. This instructable explains how you can build your own top hovering in the air like a UFO.
 
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Step 2: Earnshaw's Theorem

Did you ever try to levitate a magnet with the help of bunch of other magnets? It seems very easy: since magnets can repel each other you probably can put a bunch of magnets in circle so they equally push the other magnet towards the center of the system. Or maybe even build a sphere made of magnets that would suspend another magnet in the center. But if that’s so easy why it is so difficult to build trains that use magnetic levitation? If you try these “easy” methods you will find they all do not work. In fact back in 1842 British mathematician Samuel Earnshaw proved that it is in fact impossible to suspend a regular magnet in space with the sole help of other regular magnets statically placed around it. Well he didn’t prove exactly that, but this follows from his original theorem. The proof of the theorem contains too many Greek letters to explain it in this short instructable, so let’s just trust those smart guys who triple checked it and found it correct.

So it is impossible to suspend a magnet in space using just bunch of other magnets. But take a look at the video. There is a large ring ceramic magnet and another magnet which is also a top. And if I carefully spin the second magnet above the first one it will indeed hang in the air. How is that possible?! Let’s talk about this and a few other loopholes in the Earnshaw’s Theorem and actually build a few magnetic levitation devices. This is gonna be cool!
samkashou2 months ago
Great work. Thanks.
bobdude3 months ago
Hook it up to the bottom of my state board...
argha halder8 months ago
i wanted to levitate something easily and found it here! thanks!
jmc3cz10 months ago
Can u use magnets different from what you used?
Jussi Kontio10 months ago
Hi, could you comment on Tom Shannon's magnetic sculpture relative to Earnshaw's theorem?
It stays in the air with static magnets and does not move.
You can see it on the video at 02:00.

http://www.youtube.com/watch?v=OPA-rQyKeLY
Jussi, he clearly says he has it "down to one tether", it is not static with magnets alone, you can see the tether in this picture: http://i.imgur.com/GYfwY2g.jpg or at 1:52 in the video as the focus is changing
i am just a beginner..i have a doubt..
will it work if i rotate the base magnet (the one below using motor or smthing) and leave the small (levitating magnet) stationary.. will the small magnet levitate??
javidj1810 months ago
As you probably saw many times when playing with magnets, magnets push each other away if you try to bring together their like poles, for example, two north or two south poles. Similarly, the north pole of the external field will try to push away the “north poles” of magnetized atoms. The magnet used in magnetic levitation creates a very large magnetic field (about 100 to 1000 times larger than household magnets). In this field, all the atoms inside the frog act as very small magnets creating a field of about 2 Gauss .You may say that the frog is now built up of these tiny magnets all of which are repelled by the large magnet. The force, which is directed upwards, appears to be strong enough to compensate the force of gravity (directed downwards) that also acts on every single atom of the frog. So, the frog’s atoms do not feel any force at all and the frog floats as if it were in a spacecraft.To levitate something the size of a human being it requires more powerful magnet.

Source: http://thesecretsofscience.com/science-in-nature/magnetic-levitation/

aharner12 years ago
in soviet russia magnet repels you!
lol awesome video
mikhalchuk (author)  aharner12 years ago
aharner1, hard to believe but in the USA magnets also repel humans! :)

Human body is 60-70% water which is slightly diamagnetic. In theory human body even can levitate in strong enough magnetic field. In practice, though, it is not achievable with permanent magnets and mankind didn't build so strong electromagnet just yet.

There are electromagnets powerful enough to repel and levitate frogs and even mice.
http://www.ru.nl/hfml/research/levitation/diamagnetic/
http://www.youtube.com/watch?v=A1vyB-O5i6E
Awesome accent.
hali181 year ago
can we use any other magnets
AltonB2 years ago
Excellent instructable. I have been working on building a mechanical based clock utilizing magnetic energy in order to extend run times, as well as, general experiments. There is a lot more to magnetic energy than conventional science would have one believe. For every law of physics there IS a loophole -(remember - conventional science at one time said human flight was imppossible)- it simply takes a lot of time, effort, and energy to find it. I appreciate your very thourough explanation of the process you use and excellent instructions. Your command of the english language is very good. Keep up the good work and I intend to check out your other stuff.
Alton B.
mikhalchuk (author)  AltonB2 years ago
Thank you AltonB! I'll keep working on my English too :)
Tinmanmike2 years ago
A good source of strong donut magnets is a broken microwave. They all have two good magnets in them. Wrapping electrical tape around them makes them chip resistant and easier on your fingers.
mikhalchuk (author)  Tinmanmike2 years ago
Too bad my microwave is not broken yet :)
Thanks for the tape hint!
So, if the temperature dropped or the humidity changed it would fall?
mikhalchuk (author)  blinkyblinky2 years ago
Unfortunately yes. In a controlled environment + vacuum it can spin and levitate for days, but in regular room conditions the effect lasts for a few minutes only.
Trooper5552 years ago
Dude this is great! hope you do more.
mikhalchuk (author)  Trooper5552 years ago
Thanks Trooper555! I'm working on new stuff, hope to get it published soon.
ericCycles2 years ago
Do stacked magnets generate a stronger magnetic field than one magnet? If not, could you replace the second magnet with any magnetically neutral spacer, like a piece of styrofoam or wood?
mikhalchuk (author)  ericCycles2 years ago
ericCycles, they do. The resulting magnet is less than twice as strong, but definitely much stronger than just one.
The spacer is also there - that's the primary function of the plastic container.
If you were to force them against each other, that effect may be attained. But not if you allow them to go the direction they want.
mikhalchuk (author)  Glenn Burrow2 years ago
Glenn, you're right, thank you for the correction and clarification. BTW, for reference here are a few sources that claim the opposite (and they are wrong):

http://www.eng-tips.com/viewthread.cfm?qid=148854&page=17
http://answers.yahoo.com/question/index?qid=20100228121105AAGhoeS

To my best understanding in this particular case stacking the magnets changes the configuration of the magnetic field, makes it "more directional" and increases its strength alone the axis. So to the top it seems like the stacked magnet is more powerful that single one.

Could you please comment if this is a correct guess? Definitely with one magnet this particular top won't hover, but it does levitate on top of the stack.

Thanks alot!
Stacking magnets is not always a solution. If you chain them long enough they will self-node, and fall apart at those node points.

The only real problem with this project is that the top is balanced on a point of UNSTABLE EQUILIBRIUM, i.e., the forces that are balanced are all trying to pull the top out of the "sweet spot" whereas a pendulum is and example of STABLE equilibrium because the combined forces keep drawing it back to the point of stability.

It looks like fun to try out, but I don't want to destroy any of the decent speakers that I have...
do you have a picture/thread for this "pendulum"? I've been working on one and would be interested to see what other results look like...

cheers, tom
Letting the magnets go the way they want when stacking them makes the fields larger because of overlap but not stronger. but if put in a direction against their "wish" they have a stronger field.
Sorry, mikhalchuk, But that is not correct. The sides that contact each other cancel out. You end up with a magnet of the same strength but double the size.
mondeluz2 years ago
this system is used in alien space ships XD
for how long will this spin??
chaitanyak2 years ago
genius!
doomsdayltd2 years ago
i see what your doing, the magnetic field is holding the magnetic top in place. very simple thing with magnets but very neat.
mikhalchuk (author)  doomsdayltd2 years ago
doomsdayltd, yeap, it's magnetic field + gyroscopic effect + precession. Pretty complex and not very stable combination.
cwinget2 years ago
I've seen this at a magic shop; I guess I know how he was doing it now :B

I like your accent too, would you mind telling me your native language?
mikhalchuk (author)  cwinget2 years ago
cwinget, it's Russian accent :) Thanks for letting me know, I was always wondering how Russian accent sounds like to people who do not speak Russian.
kea2 years ago
Some years ago Ispent $40 on 1 of theese gadgets. Nobody in the family could get it to work. Not 1 of us could find the sweet spot.

It looks like it could be a great project to do.

Good work.
Cheers KIWI
mikhalchuk (author)  kea2 years ago
kea, well, maybe it's time to find that gadget, blow the dust out and give it one more try using the explanations in this video? :) I hope they can help to make that gadget hover finally.
kea mikhalchuk2 years ago
Thanks for your thoughts guys. I gave to a friend who could not get it work & he gave it away I think.
Cheers. Kea
t.rohner kea2 years ago
I think those gadgets are different. If they have a power connection, they are made with electro-magnets and some sort of sensor.(light-barrier most of the time) With this, you can levitate any ferromagnetic thing with the right weight and size. We built one from scratch with all-analog circuits some 30 years ago. In order to reduce the current through the electro magnets, we added permanent magnets. With that, we hung a little globe-pencil-sharpener out in the air. The magnets were about 1.5 inches above the globe.
dokcal2 years ago
Awesome! One of the best Instructables I've seen!

I have a Super Levitron with all the accessories--got it to hover for several hours once!--but I always wondered what the configuration of magnets in the base was. Much simpler than I thought!

One question: They used to sell a "Perpetuator" that sat under the main magnet and kept the top spinning longer and higher. It was powered by a wall transformer and didn't seem to have any moving parts.

I'm sure it must have been a very simple device, but I can't imagine what it was. I would think any variation in the magnetic field (rotating magnets or coils switching on and off) would tend to DEstabilize the top! A single big coil would certainly make it hover higher, but I don't see how it would make the top spin longer.

Any thoughts on what it might be?
mikhalchuk (author)  dokcal2 years ago
dokcal, thanks for the idea for new instructable and RTFMs episode :)

I don't have a levitron (had to figure out how it works myself) or perpetuator, so this is just a guess:

The reason why the top is not falling down is not just gyroscopic effect, but also precession. I think the Perpetuator is simply slightly pulsing at frequency between 1000K and 3000K with three or four electromagnets. If you pulse the magnets in sequence this will make precessing top "feel" like it is "skating downhill" all the time, so keep the RPMs equal to the perpetuator pulsation frequency.

Sorry about too basic terms used, I've got my physics education in non-english-speaking country thus my vocabulary lacks a lot of proper terms. I'm currently in the process of re-learning physics in english :)
Ha ha! No worries! I think your command of English outstrips my command of physics! ;>)

I had to look up "precession," but your theory certainly makes sense to me.

Thanks!
jtharkness2 years ago
Love it! Well explained also.
I wonder how long a well balanced top would stay spinning and levitated in a vacuum. Of course creating the vacuum after manually spinning the top would be an instructible all its own.
mikhalchuk (author)  jtharkness2 years ago
jtharkness, afaik it will spin for 30 minutes or so, depending on vacuum purity. Electrical motors work in vacuum, so it should not be difficult to spin the top and lift it in vacuum.

Creating a pure vacuum is a whole different story :) Thanks for the idea!
kimvellore2 years ago
I was wondering after getting this to work if you spin the bottom magnet will the top magnet keep levitating for a longer time?
mikhalchuk (author)  kimvellore2 years ago
kimvellore, in general I don't think so. The top magnet is stable until it is spinning faster than 1000RPM. It will slow down because of air resistance disregarding the bottom magnet is spinning or not.

In theory if you spin the bottom magnet it might create a kind of vortex that will help the top to spin. Also unevenly magnetized bottom magnet could create a perpetuator-like effect mentioned here in comments. But in general it will more likely destabilize the top instead.
lordmarx2 years ago
wow its cool. if it is possible to make it spin forever you can just add a coil to it to make a generator. a generator powered by magnets. no other source. it will be very good source of energy.
mikhalchuk (author)  lordmarx2 years ago
lordmarx, unfortunately it can't spin forever and won't make a perpetuum mobile. It will only stay spinning for up to a few minutes and then fall down.

In vacuum it could spin up to 30 minutes, but any kind of attachment that generates power will reduce that time.
muiftikhar2 years ago
it is a fact that i have tried several time to levitate by using magnets, but really this is an tough one to perform because of that point where all forces are acting equally :(
zjschafer2 years ago
Thats awesome!
6monkeyRS2 years ago
I like it... good job explaining it.
wainer2 years ago
Amazing. Congratulations and many thanks.
djimdy2 years ago
+1 for the matter-of-fact, dryly funny comments.
+10 because it was fun and educational.
Rybka302 years ago
A lot of pieces of electric tape :D
The Levitron..
http://www.levitron.com/

I have a few.
Also, have the super Levitron.

Great Job!
ynze2 years ago
Good job!
mikhalchuk (author)  ynze2 years ago
Thank you, ynze!
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