A magnet is an object that expresses a magnetic field. This magnetic field occurs naturally in some minerals or can be produced with modern technology. The planets (or large iron rich rocks) that make up our solar system, including our sun, are magnets.
The earth’s magnetic field keeps our moon on a gravitational leash, and the sun in our solar system exerts control over the iron rich but much smaller particles (planets and moons) within its magnetic reach. These celestial bodies are kept in orbit around the sun thanks to magnetic forces operating within its field, or sphere of influence.
About two and a half thousand years ago (600BC), ancient Greeks stumbled over a more down to earth magnetic field. Naturally occurring rocks, lodestones, attracted small pieces of iron. Iron is a chemical element forming a lot of the earth’s inner and outer core. Like a moth drawn to a flame, once an iron rich piece of material entered the lodestones magnetic territory it was inevitably captured and secured to the lodestones surface.
The lodestone, as if by divine command, seemed to be able to summon all nearby iron rich rocks to itself. The lodestone possessed what all material must have in order to be a magnet. A magnetic field. This field varies in size and strength. It depends on the individual properties of the magnet.
Around the latter stages of the Middle Age (500 AD-1500 AD) Chinese and the Vikings are credited as the first to apply this new technology in the form of a compass. A fragment of lodestone, was suspended from a length of twine or leather, or balanced on a pin or spindle and allowed to turn or spin of its own accord. The magnetised needle of lodestone invariably pointed to the earth’s North Pole.
This technology enabled seafarers to navigate their sailing ships on the high seas in foul weather or fair, night or day, and facilitated much more ambitious maritime expeditions. The lodestone was the first of the most common form of magnet, permanent magnets.
Permanent magnets are nowadays manufactured of different materials, usually iron, steel, nickel and cobalt of varying combinations, for different strengths, sizes and applications. They are deployed very widely indeed across almost all industries in different roles.
Permanent magnets are engaged as holding, fixing and fastening and release agents in place of screws, nails, bolts, springs and glues. Magnets’ fastening method is bond, and this type of bond is able to be easily terminated at a desired, or required quit force. This means materials do not need to be punctured or spoiled for the purpose of joining or holding.
Magnetic bond also facilitates intuitive or gradual power over components subject to magnetic attraction or repulsion. Applications for this nuanced energy or graduated power are everywhere around us in the built environment, especially electrical and electronics systems, manufacturing, mining and water filtration to name a few.
Electromagnetic devices, creating a magnetic field using an electrical current, have been changing the way the people do things since it’s invention in the 1880’s or so. Direct current motors, housed in many power tools and white goods like refrigerators and washing machines, are powered by an electrically abled magnetic field.
These motors convert a current of electricity into mechanical power (force and movement) and have placed in the hands of nearly everyone on earth the power to greatly improve the quality and quantity of human experience.
Being able to create and withdraw magnetic force with an electrical current like a breeze turns the blades on a windmill has generated wild imaginings. Manipulation of the tiniest of particles via the agency of magnetic fields produces light so bright we can now see and read the structure of all matter.
Advanced physics of this kind has led to profound advances in human understanding of the universe we inhabit. Research and development of this kind has also led to the treatment of humanities most dangerous diseases. From the observation of the lodestone in ancient Greece to the wonder of its modern incarnation, electromagnetism, the world has learned a lot about itself thanks to the power, the beauty, and the joys of magnetism.