# I Help artist with magnetic levitation

1. Sep 29, 2016

### dmhmaestro

Hello all!

Im a young sculptor from croatia on my last year of sculpting... Im planning in making this element that will levitate and have a rough blueprint for you to tell me would it roughly work.... the setup is ready for experimenting but the basic physics arent clear to me... did i imagine it right. So here is the drawing i made

So bottom row will be fixed all on one plate and magnets above will also be connected by element

all magnets are repelling against each other, and are inserted so they are sandwiched in between... they wouldnt move because configuration of the magnets... the one set of three wouldnt allow for x movements and the other sets wouldnt allow y movements... I think u understand by now....

What do u think??

2. Sep 29, 2016

Staff Emeritus
There is no arrangement of magnets that will do this without some sort of active feedback.

3. Sep 29, 2016

### A.T.

4. Sep 29, 2016

### dmhmaestro

But isnt the principle same as this toy

Do u have any suggestions how could i achieve such levitation otherwise... it could include power device

5. Sep 29, 2016

### dmhmaestro

I found this quote...

Earnshaw's theorem doesn't apply here. What you've done is provide a mechanical constraint, namely the plastic that holds the magnets in position. This is analogous to having a hollow cylindrical tube and dropping two cylindrical magnets into it with opposite orientation. Obviously the top one will levitate. It "wants" to flip over, but can't because of the external mechanical constraint of the plastic. Your magnets "want" to flip over, but can't because of the external mechanical constraint of the plastic.

6. Sep 29, 2016

### Khashishi

The video shows a magnet being stabilized by a plastic plate. The plate is providing the force that keeps the magnet from sliding off in that direction.

In your setup, you have rigid constraints between your magnets, but there is nothing rigid constraining the motion between the top half and bottom half. I'm pretty sure it's not possible to be stable this way.

I couldn't find a written proof for Earnshaw's theorem for extended objects, but I think it follows from linearity of the gradient function. So, if you add together two divergenceless functions, then the result is also divergenceless. The force of an extended object is the sum of external forces on each part of the object. (That's because the internal constraint forces between parts of the object cancel out over the whole object.) So, the whole thing feels a net force from a sum of many divergenceless fields. So, to avoid Earnshaw, you need a constraint force between parts of different objects.

7. Sep 29, 2016

### dmhmaestro

My setup is same as the video, but xy movement is constrained with magnets in ring formation that are x y positioned and x is keeping y steady and vice versa... Maybe the hard part is finding the sweet spot vertically... the cradle in magnets... but it would be possible right? if i put the right weight of the top object to ratio of magnet power.

To your last sentence, as i dont understand much of ur saying because im artist not physics... how would one constrain force between parts of different objects if u can explain. how can i make something like this with or without electricity

8. Sep 29, 2016

Staff Emeritus

9. Sep 30, 2016

### Tom.G

A couple ideas come to mind. Either one may work:
1) Attach two posts to the bottom plate that go thru slightly oversized holes in the top plate.
2) Hold them together with two pieces of string.

10. Sep 30, 2016

### Staff: Mentor

If those are ordinary bar magnets where the flat ends are the pole faces then I think it would be difficult to get it stable.

But you might succeed if you can instead have the field emerging outwards all the way along a side of each bar. The easiest way would be to glue a string of small neodymium disc magnets flat side uppermost where you show each bar magnet (or glue the neodymiums in a line along the inside of a length of painted plastic tubing if you want it to appear as though each is an ordinary bar magnet).

Make a small model and try it. You can buy tiny neodymium 'buttons' by the dozen.

11. Sep 30, 2016

Staff Emeritus
Nope. There is no configuration of permanent magnets that will do this. See message #3.

12. Sep 30, 2016

### litup

Look at his floating magnetic sculpture!

13. Sep 30, 2016

### CWatters

14. Sep 30, 2016

### Tom.G

See the line in the wikipedia link immediately before "Static_stability":
"In some cases the lifting force is provided by magnetic levitation, but stability is provided by a mechanical support bearing little load. This is termed pseudo-levitation."

Same as suggested in post #9 here.