Permanent magnets

A magnet is a material that produces a magnetic field. This magnetic field is invisible but is responsible for the property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.

Permanent magnets are made out of substances like magnetite (Fe₃O₄), the most magnetic naturally occurring mineral, or neodymium, a powerfully magnetic synthetic substance. The Earth itself is a huge permanent magnet, though its magnetic field is quite weak relative to its size. Humans have used the magnetic field of the Earth for navigation since the compass was invented in ancient China.

Every permanent magnet generates a magnetic field, which circulates around the magnet in a distinct pattern. The size of the magnetic field is related to the size of the magnet and its strength. The easiest way to view a magnetic field generated by a permanent magnet is to scatter iron filings around a bar of  magnet, which quickly orient themselves along the field lines. 

Every permanent magnet has two poles, named north and south, Similar poles repel while opposite poles attract. It takes a lot of effort to hold repelling poles of a magnet together, while it takes a lot of effort to remove attracting poles.

Even the most powerful permanent magnet is not as strong as the stronger electromagnets, so their applications are limited, but they still have many uses. The most significant use is as refrigerator magnets, but magnets can be found everywhere, including your hard disk, ATM and credit cards, speakers and microphones, electric motors, and toys. Electric motors work through an interaction between an electromagnet and a permanent magnet.