Take the 2-minute tour ×  I have a set of small magnetic spheres
the size of ball bearings. When many of them are built into a
cylinder such that they are hexagonally packed, there is no
magnetic attraction radially (between the walls inside).
Cylinder of magnetic balls  That is, if I try to squish the
cylinder,  getting squished by pencil  the walls do not stick
together;  enter image description here  rather it easily
resumes its cylindrical shape.  However, if I force a little
ball inside, it is attracted to the walls,  ball inside cylinder
such that when I flatten it, it stays flattened.  staying
squished on its own  What is the magnetic field doing in this
situation? Why is there no apparent attraction (and even some
resistance—though that may be frictional) radially?
share|improve this question Could you add some diagrams/pics of
the situation? It's really hard to understand how you are adding
the little ball and all. –  Manishearth Apr 21 '12 at 18:34
@Manishearth The only camera I have is my webcam