Magnetic Domains

A magnet can be made to stick to objects which contain magnetic material such as iron, even if they are not magnets. But a magnet cannot be made to stick to materials which are plastic, or cotton, or any other material, such as wood, which is not magnetic.

Because the magnetic field is so strong it causes large clusters of the irons atoms to line up with each other. The clusters of aligned atoms are called Magnetic Domains. Each domain which is perfectly magnetized is made up of millions of aligned atoms .

Magnetized & unmagnetized

The difference between a magnetized piece of iron and an ordinary piece of iron is the alignment of domains. in an unmagnetized piece of iron the domains are randomly oriented, and in a magnetized piece of iron the domains are oriented in the direction of the magnetic field.

By dropping a magnet you can displace the perfectly aligned domains, and thus the magnet becomes weaker. The more perfectly aligned domains the more stronger the magnet.

attracting = aligning domains

A piece of magnetized iron attracts a piece of un magnetized nail because it causes a growth in size of domains that are oriented in the direction of the magnetic field. When you remove the nail from the magnet the pull of it off the magnet causes most or all of the domains to return to a random arrangement.

Even when the atoms are oriented randomly, exposure to a nearby magnet may cause them to line up with the magnetic field. Substances that do this easily, such as iron or nickel, can be 'magnetized.'
Other substances, in which the atoms remain randomly oriented even when exposed to a magnet, such as copper, wood or plastic

Review