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Name: Paul
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Question:
What would happen if you took a basketball and lined the inside with magnets, all positive facing in (towards the center of the ball,) and then took a ping-pong ball and lined the outside with magnets all positive facing out, and then dropped the ping-pong ball into the center of the basketball-- would the force of repulsion be greater than the force of gravity causing the ping-pong ball to float in the middle of the basketball until it found a point of stasis? I have tried to build a 'magnetball' myself but I was unable to find magnets shaped in such a way that they would completely cover the entire surface of both balls, as a result the spaces between the magnets had the opposite polarity creating areas of attraction.



Replies:
Paul,

It is not possible to make a CLOSED sphere with the outside being only one pole. The magnetic fields from the inside surface would cancel the field from the outside surface, even if you could get the magnets close enough together. Unlike electric charge, magnets are not positive pole at one end and negative pole at the other. Every molecule is a magnet. Every zone of aligned molecules is a magnet. A day-to-day magnet is actually many tiny magnets lined up with each other.

If you try to put strong magnets side by side, all pointing in the same direction, they can join, but there must be a way for the magnetic field to circle around from one pole to the other. If you somehow managed to align all the molecules in a sphere, the magnetic fields from the inner surface would still pass through the material to the outer surface, in both directions. The material would behave like many very narrow magnets with alternating alignments. It would work like half the magnets were pointing inward and half were pointing outward, all intermingled. There would not be a magnetic field within the ball.

If you did build this structure, with the zero field at the center, over a short time the molecules would rotate within the magnetized material. You would probably end up with one pole at one end and the other pole at the other end, very much like the magnetic field pattern of the Earth.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College



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