If i am placing two rock(stone) chips closer with a wider area of contact and rotating another rock stone around these two chips(having close contact) for some time (around 30 sec) and try to separate the two stones that i put into contact at first, it seems there is an attraction between the two. Why this is happening? Please explain the phenomenon behind it.
The stone contains a ferromagnetic material, which is a material with a spontaneous magnetization. In thermal equilibrium, such a material aligns itself to be magnetized in the same direction. But over a very large distance, you can reduce the bulk energy by randomizing the field direction, so that it pays to put in very large domain walls separating different magnitization regions.
When there is an external magnetic field, it makes the domains line up. The dynamics of the domains is extremely slow, so you end up with a magnetized rock. You are seeing magnetization caused by placing a ferromagnet in the magnetic field of another. You don't need to rotate to see this, just hold them close and wait.
|show 6 more comments|