How can you turn a paper clip into a magnet?
You can turn a paper clip into a magnet by rubbing a strong magnet several times over the surface of the paper clip. The more you drag the magnet over the paper clip, the stronger the paper clip will become magnetized. The same thing happened with the metal in the experiment. When we rubbed the magnet over the surface of the metal, some of the magnetic domains aligned and the metal became partially magnetized. When we rubbed the magnet over the metal a second time, more of the magnetic domains became aligned and the metal became a stronger magnet.
What is different about ferromagnetic materials that make them strongly magnetic?
In ferromagnetic materials, the magnetic moments of a relatively large number of atoms are aligned parallel to each other to create areas of strong magnetization within the material. These areas, which are approximately a millimeter in size, contain billions of aligned atoms and are called magnetic domains. Magnetic domains are always present in ferromagnetic materials due to the way the atoms bond to form the material. However, when a ferromagnetic material is in the unmagnetized condition, the magnetic domains are randomly oriented so that the magnetic field strength in the piece of material is zero.
In the unmagnetized condition, the material will be attracted to a magnet but will not act as a magnet. That is to say, two unmagnetized pieces of ferromagnetic material will not be attracted to each other. When a ferromagnetic material is magnetized, the magnetic domains align parallel to each other to produce a large net field strength in the material and the material becomes magnetic.
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