I‘m curious how matter affects magnetic fields. If you put objects of different densities between two magnets, will it affect how strongly they attract? All other things being equal? For example, I have two wickedly powerful rare-earth magnets that I like to play with. I can put them on either side of my desk here, and they‘ll easily stick together through the thickness of the desk (about 1.) What I want to know is, if I had some much denser (non metal to keep it simple) material of the same thickness, like say concrete, would they still stick together with the same force?
it depends on the material. there are in general 3 types of materials; diaparaferro-magnetic materials. diamagnetic and paramagnetic materials do alter the magnetic field, but very very slightly. the one of interest is ferromagnetic materials. when exposed to external fields, the molecules in these materials allign in such a way to modify the field (amplify it). and yes, the denser the material the more intense the effect. to fully understand why ferro materials do this requires quantum mechanics. however, you can think of the atoms in these materials a tiny tiny magnets with north and south poles, but not quite. when exposed to the field they allign in the direction of the field, thereby increasing it's strength by adding their own to it, so to speak. the denser the material, the more of these di-poles and therefore a stronger field.
