Standard 6.3--Permanent and Temporary Magnets

Standard 6.3: Explain how objects like the earth and metals can be permanent or temporary magnets.

                                                                   MARS INTERIOR                                                           

                                                                  (solid)

One of the key concepts that we learned during this unit is that moving charges generate magnetic fields. We know that Earth generates a magnetic field because the outer core of Earth is molten, meaning that there are very hot metals such as iron and nickel moving around the outer core in liquid form . These metals have charges and these moving charges are what makes Earth one large magnet. In addition , Earth's rotation around the sun helps the current of the moving charges in the outer core to generate Earth's magnetic field that protects us from foreign space objects penetrating our atmosphere. Other planets aren't so lucky. Mars, for example, does not have a molten outer core and therefore no moving charges so it does not have a magnetic field. 


         EARTH INTERIOR

A magnetic domain is a region in which the magnetic fields of atoms are aligned (pointing in the same direction) and grouped together. Earth is a PERMANENT MAGNET, meaning that the domains are always aligned. As long as Earth has moving charges, it will always be magnetic. Paper clips are TEMPORARY MAGNETS,  meaning that they can be magnetic at times and not at others. When a paper clip comes in close contact with a permanent magnet, the domains of the paper clip line up and it becomes temporarily magnetic. When the paper clip is removed from the permanent magnet's magnetic field, the domains become askew and the paper clip is no longer magnetic. Items such as paper are never magnetic because their domains never align even when they come in contact with another magnet.