The feeling of enjoyment you get when you are a kid playing with magnets is unforgettable. But, it’s not just the children. The phenomenon behind magnets is something that has fascinated people across all cultures for centuries. As far back as 600 BC, Greek philosophers have studied and described the magnetic properties of ferrite stones. After some major scientific theories developed by physicists in the 19th century, our understanding of magnetism has expanded a lot. It is no longer seen as a mystic force, but as one of the key integral concepts that explain how the Universe works.
Magnetic force is a type of non-contact force. Similar to electrical and gravitational forces, the magnetic force does not require a direct contact between the bodies. When objects with magnetic characteristics are brought in proximity to each other, there is either attraction or repulsion, depending on their orientation. This magnetic force is a part of a fundamental force of nature called the electro-magnetic force. In a nutshell, magnetic force is a consequence of moving charges.
Everything is made of atomic particles. And every atomic particle has a charge – positive, negative or neutral. When the free-standing electrons spin around the nucleus of an atom, they generate a magnetic field. But what is magnetic field? A magnetic field can be defined as the area around a magnet which can exert a magnetic force. In objects like cloth or paper, equal number of electrons flow in opposite directions and cancel out the magnetism. This is why even though all objects have magnetic properties, they do not exhibit magnetic behaviour. In metals like Iron and Cobalt, most electrons spin in the same direction. This makes way for a strong magnetic field and thereby results in magnetic force. When another magnetic object enters this field, repulsion or attraction occurs based on the direction in which the charges flow. All magnets have north and south poles. While opposite poles are attracted to each other, the same poles repel.
For example, when you bring a piece of iron close to a toy magnet, the atoms in the metal respond to the magnetic field and are immediately attracted. In this case, the toy magnet creates the magnetic field and the piece of metal becomes magnetised. This interaction is reversed when you take two toy magnets and place them in a way where the same poles face each other. A moving magnet produces electricity and can result in electric force, under certain conditions. This is why magnetism and electricity are closely related. The Scottish physicist James Maxwell clerk was the first to theorize the relationship between the two and wrote the equation that explains the phenomenon. When you think of magnets, most of us think of the kind you stick on your refrigerators. But our whole Earth is actually one giant magnet! The magnetic needle in a compass spins, because it is aligning itself with the planet’s magnetic field.
When you think about it, magnetism is very important to human life. Without magnetism, there would be no electricity, motors or generators. Modern life would never be the same.