# Physics project help -- magnetism

Is it possible to make a magnet that slides down a pole with no friction? The magnet would be a cylinder, the exterior would be N and the interior S. It would slide down the S end of a magnetized pole. That way the the pole would push equally on the sides of the interior of the cylinder. This is for my middle school science fair.

Related Other Physics Topics News on Phys.org
Dale
Mentor
You cannot have a magnet whose exterior is a north pole. That would be a magnetic monopole and would be a Nobel prize project, not a middle school science fair project.

You could have bar magnets that slide through a copper tube, or something similar.

You cannot have a magnet whose exterior is a north pole. That would be a magnetic monopole and would be a Nobel prize project, not a middle school science fair project.

You could have bar magnets that slide through a copper tube, or something similar.
Can you expand on that? How would that work?

Last edited by a moderator:
berkeman
Mentor
Is it possible to make a magnet that slides down a pole with no friction? The magnet would be a cylinder, the exterior would be N and the interior S. It would slide down the S end of a magnetized pole. That way the the pole would push equally on the sides of the interior of the cylinder. This is for my middle school science fair.
You cannot have a magnet whose exterior is a north pole. That would be a magnetic monopole and would be a Nobel prize project, not a middle school science fair project.

You could have bar magnets that slide through a copper tube, or something similar.
It seems like you could bolt together a number of thin rectangular magnets in the shape of a cylinder, with their S ends pressed together at the inner radius, and the outer N ends spaced a bit apart.

But even with that, you couldn't have a "pole" that was the S end of a magnet, so the overall idea still doesn't seem to work.

You could look into how maglev trains work -- that will give you an idea of a geometry that uses magnetic levitation to minimize friction...

Dale
Mentor
Just buy some cylindrical bar magnets and then buy a copper tube that is slightly wider. You can use that kind of rig to demonstrate eddy currents.

Could this type go magnet be made?

Just buy some cylindrical bar magnets and then buy a copper tube that is slightly wider. You can use that kind of rig to demonstrate eddy currents.
Above

Dale
Mentor
Ah, I completely misunderstood the geometry. I would call that shape a tube, not a cylinder. Please disregard my previous comments. I believe that you could indeed have a tube magnet with the poles as described in your OP. My apologies.

1 person
Dale
Mentor
You want to look for a radially magnetized ring or tube magnet. They are apparently difficult to manufacture, so they are going to be expensive.

CWatters