The History on Magnets
- The earliest recorded use of magnets was to make a floating compass, which had its first detailed European description in 1269, by Petrus Peregrinus de Marincourt. The earliest reports for the compass in China come from 200 years earlier, and it's listed as one of the four great inventions in Chinese culture. The explanation of why the compass worked (it aligns with the Earth's magnetic field) came about with the writings of William Gilbert in 1600, presaging the rise of Galileo, Kepler and Newton.
- The similarities between objects with electric charges and the repulsion and attraction effect of magnets was highlighted and many experiments detailed these effects, laying the foundational work on electricity in science and electromagnetism. Facilitating this research, Gowen Knight became the first person on record to sell artificial magnets for scientific research and the creation of navigational devices. A decade later, a book on making steel magnets was published by John Mitchell.
- Electromagnets were identified in the 1820s, when Hans Christian Oersted discovered that a current flowing through a wire would pull a compass needle placed beside it. This was expanded on by Andre Marie Ampere, who discovered the balanced electrical equations after observing that the direction of current in a wire changed which pole of a magnet was attracted. This mathematical basis for electricity and electromagnetism is the foundation of modern electrical generation and current diagrams. By the mid-1830s, electromagnets were available for researchers and were the key missing ingredient to the telegraph.
- The invention of the electromagnet sped Englishman Michael Faraday down a different path: If electrical currents could create magnetic forces, was the reverse also true? Could magnets create electrical current? His early experiments demonstrated that a magnet moving inside a coil of copper wire produced a current that could be measured. Faraday's description of the experiment lead to the alternator, and the use of magnets in electrical generation, a process still used today. It also provided the basis of the DC motor, used in nearly every electrical device that moves today.
- Before the 20th century, most magnets remained on the same general order of strength as lodestones. They were greatly improved in the 20th century, with the cobalt-steel magnet in 1927, then nickel aluminum iron magnets in the 1930s, ceramic magnets in the 1950s and rare earth magnets in the 1960s, and neodymium-iron-boron magnets in the 1990s.