Lodestone is a natural permanent magnet. Other permanent magnets can be made by subjecting certain materials to a magnetic force. When the force is removed, these materials retain their own magnetic properties. They are made by surrounding certain materials with a spool of wire. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get an original essay The first thing that was made from magnetite was a compass. They believe it happened in Europe between 1100 and 1200 AD. All magnets have two points where the magnetic force is greatest. These two points are called the poles. For a rectangular or cylindrical bar magnet, these poles would be at opposite ends. One pole is called the northern research pole, or north pole, and the other pole is called the southern research pole, or south pole. This terminology reflects one of the first uses of magnetic materials such as the magnet. When hung from a rope, the north pole of these early, rudimentary compasses always sought or pointed north. These aided permanent magnet magnetites contain magnetite, a hard, crystalline iron ferrite mineral that derives its magnetism from the effect of the Earth's magnetic field on it. Various steel alloys can also be magnetized. The first major step in the development of more efficient permanent magnet materials took place in the 1930s with the development of Alnico alloy magnets. These magnets get their name from the chemical symbols for the aluminum-nickel-cobalt elements used to make the alloy. Once magnetized, Alnico magnets have between 5 and 17 times the magnetic strength of magnetite to determine which direction to follow to reach distant lands and return home. In the 1970s, researchers developed permanent magnets made from heat-melted samarium-cobalt powder. Just as the materials are different for different types of magnets, the manufacturing processes are also different. Many electromagnets are cast using standard metal casting techniques. Flexible permanent magnets are formed during a plastic extrusion process in which materials are mixed, heated and forced through a contoured opening under pressure. Electromagnets: The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet which requires no power, an electromagnet requires a continuous supply of current to maintain the magnetic field. An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets generally consist of insulated wires wound into a coil. A current passing through the wire creates a magnetic field which is concentrated in the hole in the center of the coil. The turns of wire are often wound around a magnetic core made of a ferromagnetic or ferrimagnetic material such as iron; the magnetic core concentrates the magnetic flux and makes a stronger magnet. Beginning in 1830, American scientist Joseph Henry systematically improved and popularized the electromagnet. Using wire insulated by silk thread and drawing inspiration from Schweigger's use of several turns of wire to make a galvanometer, he was able to wind several layers of wire onto cores, creating powerful magnets with thousands of turns of wire, one of which can support 2,063 pounds..