People have been using magnets for a long time. The first written mention is in correspondence between Aristotle and Thales of Miletus in 600 BC . Magnets known as lodestones, a naturally occurring iron oxide magnet, were known to the ancient Greeks in the city of Magnesia, possible accounting for the name. Magnets were also being used at that time for some type of medical treatment in India. Human blood cells have hemoglobin in them which contains iron. The property that iron is attracted by a lodestone has been observed by the Chinese in 400 BC. The notion of making a fine needle of iron and using it to navigate by the Earth’s magnetic field became popular in China around the year 1000. In 1187 Alexander Neckham was the first European to write about the compass and its use in navigation.
William Gilbert in 1600 wrote the first scientific work on magnetism and is credited with the discovery of the Earth’s magnetic field, and that the magnetic field and the difference between the center of the Earth’s rotation from the magnetic center. Gilbert’s work was so meticulous that Galileo credited him with the creation of the scientific method. Gilbert also differentiated magnetic attraction from electrostatic attraction and did a great deal of the first scientific treatment of these forces. The next major work on magnetism and observation of electromagnetism did not take place until the 1820’s when Faraday created the first electric motor.
Magnetism, like electricity, has been one of the most important elements of modern technology, and yet for all out technological sophistication, both phenomena are not very well understood. Magnetism and electricity both have observable rules and we are able to manipulate them to perform useful tasks, but they are still quite mysterious, their “inner workings” tied to atomic forces that today’s most advanced physics have not been able to fully explain.
The technologies made possible by understanding magnetism are everywhere around us. Hard disk drive motors are among the most sophisticated electromagnetic machines in the world today. Digital memory with incredible density is another application of the same. Magnetic resonance imaging the is able to look inside the human body would not be possible with the ability to manipulate magnetism.
We circle the globe, and peer into the details of the human body, yet barely understand what magnetism is. We can postulate and use the magnetic monopole to quantify it, and we can see the effects on permeable materials as they become magnetized. The unique properties of metal alloys that are permeable were first studied in detail in the 1950’s and not much application has been found since. Grain orientation of magnetic alloys and the properties of the materials as the molecules come into alignment are still being studied.
At the end of the day, magnetism as a technology is critically important to the electric motor. There are still many mysteries that we need to uncover.