History of Magnets
Most people's familiarity with magnets come from the various assortments of magnets that help keep their to-do lists attached to the fridge. Others may remember magnets from their childhood toy - Magnadoodles. It's easy to understand the fascination that humans have with magnets, it's capable not only of attracting metal objects, but also of creating electricity and allowing us to listen to music. Magnets were allegedly first discovered in Greece by a shepard named Magnes (hence the name magnets). Originally, these stones were called lodestones and were used in some cases to pull out nails from boats. Later on, people began finding other uses for magnets like navigation.
Earth itself can be considered one large magnet. As most of us know, there is a magnetic north and south. A compass has a magnet in it as well and will point to magnetic north. This is great for directions and the compass was used very early on. There is some, albeit very little, evidence that the Olmecs could have created the first compass from a geomagnetic lodestone. If so, then this would predate the first known compass (from China) by more than a millenium. At this point, this discovery is speculation.
The Chinese, in fact, have a long history of the use of magnetism, dating back to 4th century BC in a book titled "Book of the Devil Valley Master". However, the very first use of a magnetized needle for navigational purposes was around 1119 CE. A typical compass consisted of a magnetic needle floating in water (these are the simplest types of compasses). Later, this invention was adopted over the world and especially by the Europeans in 1190. There is quite a bit of contestation whether Europeans came up with the compass independently or not. Still it seems unlikely the Europeans came up with the idea themselves as:
1. The shapes of the common compass are similar in both China and Europe
2. The first introduction of magnets in Europe is very close to the one in China (a mere 73 years)
3. There is no evidence suggesting there was knowledge in Europe of magnetism or how to induce it in an iron rod.
Besides the use of magnets as compasses, one of the other great finds was electromagnets. These magnets produce a magnetic field when charged by electricity and cease when there is no current. All of these electromagnets require a conductor of some kind as well as wires. There are many uses of these electromagnets including doorbells, motors, magnetic locks, magnetic recording/data storage equipment and more. For those that love music, magnets also allow us to listen to our favorite songs in speakers. An electromagnet and permanent magnet interact with each other, which pushes the coil inside the speaker to move. This creates the sound waves that we hear. Headphones work in a similar way although there is only one stationary magnetic element that sets up the static magnetic field.
Not only can electricity make magnets, but magnets can also create electricity. By quickly pulling a magnet through metal wires (like copper) that have electrons that can be readily moved, electricity is made! This allows for the creation of large vehicles that are powered solely by magnets, such as bullet trains that solely use the Magnetic Levitation (or maglev). These are employed in various parts of the world including Japan, Korea and France. Not only that, but electromagnetism is now being used to create wireless electricity!
All in all, we have an attraction to magnets for useful purposes but have also discovered other ways to use them such as the magnetic bracelets that are supposed to strengthen or chi to using magnetite as decoration pieces. Many have used it as a way of expressing art such as Sachiko Kodama. Still others have used the magnetic property and our fascination with fridge ornaments to create