Magnetism

Magnetism:
How can objects like the earth and metals be permanent or temporary magnets?

Objects like the earth and metals can be permanent or temporary magnets depending on their domains. A magnetic domain is a part of a material that determines its magnetism. One example of an item with no domains would be a piece of paper. A piece of paper has no domains, and therefore it can never be magnetic. An object that has domains, but those domains are not lined up would be a paper clip. The paper clip's domains are not lined up until a magnet comes along and aligns its domains, making it magnetic. And finally, an object with domains that are always lined up would be the earth. The moving metals inside of the earth create a magnetic field, and charges on the outer core moving like a solenoid create a huge, permament magnetic field.