Why strong magnet in iron, over a period of time after the block has a certain magnetism?
Generally, the magnetic distances of each domain are different, and the magnetic fields cancel each other, so the whole material is not magnetic.
This is the phenomenon of magnetization. Magnetization is the process of ordering magnetic material which is not magnetic. Magnetic materials are divided into many tiny regions, each of which is called a magnetic domain, each of which has its own magnetic distance (i.e., a tiny magnetic field).
When the direction of each domain is uniform, the whole material shows magnetism. The so-called magnetization is to make the magnetic domain of the magnetic domain in the magnetic material become consistent. When the material that does not exhibit magnetism is placed into another strong magnetic field, it is magnetized, but not all materials can be magnetized, and only a few metals and metal compounds can be magnetized. Iron can be magnetized.
