A History of Magnets and Their Many Uses
July 21, 2008
Magnets have been in use for thousands of years. The first known reference to magnetism dates back to the 4th century B.C.E. from a Chinese literary work called “Book of the Devil Valley Master.” In this book, it was written that “lodestone attracts iron to it.” Lodestone is a type of magnetite metal with a special crystalline structure that can naturally create a magnetic field, thereby attracting and magnetizing iron. By the 12th century A.D., Chinese sailors were using lodestone rocks as compasses for sea navigation.
At one point in history, it was thought that lodestone could be used to keep the skin looking youthful. In fact, Cleopatra was reported to have slept on a lodestone for many years. The therapeutic reputation of lodestone was passed on to the Greeks, as well, who began using magnets for healing around 2500 B.C.E. Aristotle and Plato frequently wrote of the benefits of lodestones in their works.
Magnets have been used in Chinese medicine since about 2000 B.C.E., in conjunction with reflexology and acupuncture. Magnets are still used today as a first line of treatment for many common complaints. Warm lodestones are often placed strategically on a patient’s back because it is believed that they help to align the spirit. Modern day medical science is utilizing magnetism now more than ever: magnetoencephalography (MEG) is used to measure brain activity, and we have been using shock therapy to start a stopped heart for years now.
Today, the use of magnets in industrial and mechanical applications is quite common. Magnets are the basic driving force for all electric motors and electric generators. Every electric motor is dependent upon magnets with electrical coils surrounding the magnet. As the current moves, the magnet follows in sequence. Electro-magnets are used in telegraphs, telephones, computers, cell phones, door bells, tape recorders, etc. Electromagnets are used on cranes to pick up and drop heavy loads, as well as in industrial conveyor systems to pull metal parts out of various materials. Truck mounted magnets are also used to clean up construction sites and prevent nails in vehicle tires.
Magnet technology has also been used to develop the MAGLEV (magnetically levitated train). The train track is a single rail system with the train levitating above the track. This virtually eliminates all friction and wear on the train and the track. Fluctuating electrical currents drive the train, and because friction is not a factor, the trains can move at very high speeds. Theoretically, the speed could be infinite, if it were not for wind resistance on the train cars.
On June 6, 2008 President Bush signed a bill that will support the building of the first MAGLEV train between Las Vegas, Nevada and Disneyland in California. This project will enable passengers to travel the distance in just under 2 hours, traveling at speeds up to 300 MPH. Traveling in a car, this same trip would take just over 4 hours.
With need for more efficient energy and cleaner methods of transportation, magnet technology is becoming increasingly more important. Man’s understanding of magnetism and its many uses is often times considered to be one of our greatest achievements, along with creating fire and the invention of the wheel. As time goes on and technology continues to develop, our understanding of magnets will surely grow and continue to play a vital role in our everyday lives.
About the Author:
Ellen Bell works for Home Products n’ More, a company dedicated to providing high quality products for your home, garden, and auto. Home Products n’ More offers a line of magnetic separator conveyors, offroad magnetic sweepers, and rare earth magnets.