Electromagnets are a variety of magnets in which the magnetic pull is created via electricity, not through innate magnetic properties. While electromagnets have been in existence for more than a century, the technology revolving around them has changed immensely over the years, as has their ability and strength.
Electromagnets where first produced by William Sturgeon in 1823. Sturgeon, a British scientist, had conceived of the project some time before and created the first working electromagnet out of iron, copper wire and a battery. This simple electromagnet was capable of lifting far more than it weighed using only magnetic attraction. As time went on, scientists created more powerful electromagnets. Modern electromagnets can lift tons of metal with relative ease.
Electromagnets work on a relatively uniform principle. Electrical wire is wrapped in a coil around an iron bar or hoop. When electricity is run through the coil, it causes the iron inside to become highly magnetised. This magnetic force only lasts so long as electricity is run through the wires, and its intensity varies depending on the strength of the electrical charge. This is the main difference between a traditional magnet and an electromagnet. Electromagnets are variable in strength and can have their magnetic fields turned off, whereas normal magnets have a static strength level and cannot be turned off.
While most electromagnets are fairly standardised, there are certain types of electromagnets that bear further mention. Superconducting electromagnets function without the iron core that is found in most electromagnets and are used for extremely high-power applications because of their immense strength. Bitter electromagnets were invented in 1933 and are named after their inventor, Francis Bitter. The Bitter electromagnet is similar to a normal electromagnet but adds many disc-shaped electromagnets stacked together and working with one another. This results in an extremely powerful sort of electromagnet, albeit a very complex design.
Benefits from electromagnets are massive. Electromagnets are extremely useful in industrial processes and make assembly-line work in most modern factories possible. Electromagnets are also used in MRI machines, magnetic locks, magnetic sound recording (including computer hard discs, video tapes and cassettes) and many types of motors.
Electromagnets are relatively easy to identify when compared with normal magnets. The major difference is that electromagnets require a flow of electricity to function. Without electricity they don't create any magnetic field and are useless.