a)  This model is based on the idea that inside a ferromagnetic object there are a very large number of tiny entities, sometimes called magnetic domains. Each magnetic domain is assumed to behave like a tiny bar magnet, with north (N) and south (S) poles. b.)The magnetic effects of the north and south poles of the domains therefore cancel each other out throughout the entire object, and produce no net magnetic effect. When a ferromagnetic object is fully magnetized, all the domains become aligned, pointing in the same direction. c.) The end of the object toward which all the north poles of the domains are aligned becomes the North Pole of the magnet; the end toward which all the south poles of the domains are aligned becomes the South Pole of the magnet. d.) When one pole of a permanent magnet is rubbed along the ferromagnetic material (e.g. a nail) in one particular direction, the opposite poles of all the domains are attracted to it and rotate to follow it. e.) When one pole of a permanent magnet is held close to a ferromagnetic material, its magnetic influence causes the domains in the material to rotate by attracting their opposite poles. The alignment of the domains in a magnetized ferromagnetic material can be disrupted by making them move around. Two techniques that work are:

i) ‘Shocking’ by vigorously hitting the material (or throwing it on the floor) and ii) Heatingthematerialforseveralseconds..