Magnets are materials or objects which have a field around them which attracts other objects or materials constructed from materials that are ferromagnetic. One such common ferromagnetic material is iron. Also, magnets can repel and attract other magnets. It is usually only solids which become magnetized but liquid can also become magnetized when containting small particals which are ferromagnetic and near a magnetic field. This kind of luquid is termed ferrofluid. Materials which are not ferromagnetic also respond to magetic fields but not enough to be be labeled as magnetic.
Most magnetics are permanent and retain their magnetic fields without the need for another magnetic field to be present. This are usually constructed of cobalt, iron, or nickel. Some substances such as lodestone are naturally magnetized, however most perminant magnets are made by putting a powerful magnetic field on a ferromagetic material. Ferromagnetic materials may be considered "hard" or "soft" depending upon their magnetic ability. A soft substance (i.e. annealed iron) may be magnetized however it will lose the magnetic field quickly if it is not near other magnets.
Magnets were originally used for navigational purposes in compasses. Today we think about magnets as a compass or a device to hold papers to metal surfaces like a refrigerator magnet. However there are so many more ways to use them. For example: magnetic tapes are utilized to put information on cassette and VHS tapes, and credit and ATM cards. Computers utilize magetic materials as well. The hard disk utilizes a drive shaft which rotates, which is surrounded by magnets. It also has a ferrofluid in the space between the magnets and the shaft. This has it act like a liquid seal. Magnets can also be utilize in microphones, speakers, televisions, transformers, and generators. Magnetic resonance imaging are used in hospitals in order to look at organs without surgery.
A special kind of magnets is the electromagnet which has a magnetic field made by an electric current. Typically a coild wire with electric current going through it is twisted around an iron core, amplifying the strength of the field made by the electric current going through it. A great advantage to this magnet is that you may control the strength by controlling the current of electricity going through it. This magnet is used mostly in computers.
There are many health concerns about being exposed to a lot of electromagetic radiations yet magnets are very beneficial to society. Aside from technological applications, magnets may be used for toys, education, and as well as the arts. Artists around the world make moving art from magnets all the time. Many new uses are being found constantly for magnets in today's ever growing and changing world.
One of the first forces of nature to be discovered by humans was magnets. The history of magnets dates back as early as the 4th century BC when the attraction between lodestone and iron was documented in Chinese literature. Lodestone creates its own magnetic force and is referred to as a natural permanent magnet. Iron is an induced magnet, in that it only becomes magnetized by the presence of a permanent magnet, like lodestone and is what creates the attraction. Ferrofluid is a liquid form induced magnet. The liquid, in the presence of a permanent magnet, will become magnetized.
Throughout history, there has been many uses and applications of magnets, most of which has led to the development in modern technological advancements. Legend has it that Cleopatra slept on a lodestone bed for years because she believed that the aging process was slowed down by its magnetic properties. Science has not yet established nor proven a correlation between magnets and retaining youthfulness, but they are still widely used today in alternative medicine. They are recommended for many common ailments. Many athletes, both men and women, utilize tectonic magnets for relief from pain and inflammation. Alternative health professionals often place warmed lodestones on their patient's back. It is thought they help realign the spirit and produce a sense of well being. Modern medical science uses magnets on a regular basis, such as in magneto encephalography which monitors activity of the brain or in magnetic shock therapy which produces a current used to restart a heart that has stopped beating.
Many NASA experiments have used magnets and ferrofluid in the spacecraft's altitude control system. In today's medicine, ferrofluid is used in cancer detection and there is continual experimentations within various cancer treatments using ferrofluids and magnets. Magnetic hyperthermia, which is based upon the body's natural ability to fight many illnesses with heat, utilizes the warmth released by ferrofluid when placed in an alternating magnetic field to recreate natural body functions. Much more research is needed before the magnet's true potential is established within the world of medicine.
MAGLEV-magnetically levitated train-is another remarkable invention using the power of magnets that has come into existence just recently. The MAGLEV levitates above the rail track which eliminates virtually all friction on both the track and the train which allows for excessively high speeds. President Bush signed a bill in 2008 in support of the first MAGLEV train. The train was scheduled to travel between California and Las Vegas. This journey would allow passengers to travel at speeds upwards of 300 miles per hour all due to the wonders of magnetic technology. This technology would cut travel time in half compared to traveling by car.
Modern magnetic technology continues to advance at astounding rates and it would seem likely that we are on the verge of new and cutting edge discoveries that could have a profound impact on our daily lives and as part of modern inventions.
