Question on magnetic levitation project.

[jplecas]

Hello everyone!

My apologies if i am not posting in the correct subforum.

I have a couple questions on an art project i am getting ready to start on, and was not able to find what I was looking for. I am new to this board and should let you all know right now that I failed high school physics miserably.. Please be patient with me

Rather than drawing out a bunch of pictures for you all, Ill post a link to a video to show what I am trying to build.

http://www.youtube.com/watch?v=L5NrqN6gDFA&feature=related

I am looking to build something similar to this, but much larger. I would like the cylinder to be 3 or 4 feet long, maybe 6 to 12 inches in diameter. I imagine that I would end up needing two magnets similar to this?

http://www.magnet4less.com/product_info.php?products_id=450

The more I look into it, the more I am beginning to think that I am getting in over my head. It seems that there will be so many variables with this. And I would like the final product to be somewhat stable.

I am curious as to what the magnetic fields would look like for this project? I have been tossing around the idea of somehow integrating ferrofluid into the design, and think it would create an impressive visual display.

I got the idea of applying the ferrofluid to both cylinder ring magnets, as well as the four base magnets underneath. At first I figured the ferrofluid would jump from the bottom magnets to the cylinder, creating an illusion of the liquid holding the cylinder up in the air. But this would not happen since the magnetic fields between the two are resisting each other, and the ferrofluid follows the lines of the magnetic fields, correct?

I guess I don't have a specific question about this project, other than how would the magnetic fields look, and how might the ferrofluid react to this particular setup. Besides that I would love any input you guys might be able to give me. It would help me tremendously, and I would really love to build this thing!

Thank you all!

Joseph

 

[JaredJames]

I assume you aren't looking to support anything with your setup?

The basic concept is very much as per the video, but you would need to keep the weight down otherwise you may have to switch to electromagnets.

I'm aware how the ferrofluid would react to an individual magnet, but I'm not so sure about with two in this configuration.

The actual design is no more complicated than in the video.

 

[jplecas]

thanks for the quick reply!

Yes, I won't have much trouble building the setup, but my concern is ordering too strong or too weak of magnets. Or overlooking something else, resulting in an unstable cylinder.

The cylinder will be supported on one side, either by a sheet of plexiglass or a large mirror. I am thinking about linking the two disks together with pvc pipe, running through the centers. The pipe will extend off to one end and eventually taper. This is the side that will be touching the glass/mirror. the same way the pencil tip does in the video.

If I understand this setup correctly.. all of the magnets polarity is split vertically, in the same direction. So i would imagine that the field would look almost like an 8 from the side. If I use enough ferrofluid, could it potentially form the shape of an 8 between the cylinder and base? I wouldn't be surprised if i am mistaken about how the field would look.. I can't seem to find any pictures showing an example of two magnets with both - and + poles facing each other at the same time. As this setup would be.

The attached image would be a top view, looking down at the setup.

 

[JaredJames]

I would recommend inverting one of the pairs of magnet rings, otherwise it could just 'slide' forward and so the rear - (of the ring) will contact the forward + (of the support magnet).

So your magnet rings will be -------( - , + )-------------( + , - )-------|

And the mag supports will be -------| - , + |-------------| + , - |-------|

This is of course assuming it is split down the middle as per your drawing. The split could be outside of ring North, inside of ring South (like this drawing: https://www.physicsforums.com/showthread.php?t=341215).

Aside from that there's no more to do. Strength wise, you need to check the weight of the rig compared to the repulsive force available.

No, it wouldn't make any 'figure of eight'.