Magnet is something that attracts kids and adults alike. How many times have you spun a trick where you made an object erratically when all you were doing was moving a magnet under the table? And each time we have a magnet in our hands, we can’t stop wondering how it works. Let’s put all speculations to rest and find out how magnets work.
Some Basic Properties of a Magnet
Magnets attract metal objects like iron, cobalt, nickel etc. Such metals that are attracted by magnets are called magnetizable materials. When you suspend a magnet in the air, after some time they get aligned along the Earth’s north-south pole axis. The end of the magnet that points towards Earth’s North Pole is the magnet’s north pole and the opposite end is its south pole. If you try to connect the same, say south, poles of two magnets, they will repel each other. If you try to connect opposite poles of the two magnets, they will attract. Let’s now try to understand why and how all these things happens.
Magnetic Fields of Electrons
Like all living things, including humans, animals, plants, birds, etc., are made up of tiny cells that have life ticking within them, all non-living things are made of atoms. Atoms are further made up of electrons. You already know from a previous post that moving electrons generate current and wires carrying current create a magnetic field around them. So, we can safely conclude that it’s moving electrons that create magnetic field.
Electrons as Tiny Magnets
Every electron has an angular axis of rotation around which it spins. The electron also rotates round the nucleus of the atom. These two motions produce a magnetic field around the electron, as shown in Figure 1. These tiny magnets, aka electrons, have north and south poles as well.
Figure 1: Magnetic Field – From North to South
There is another property of these tiny magnets, aka electrons, that comes into play here. Electrons are usually found in pairs. The two electrons forming a pair spin in opposite directions. Due to this, the magnetic field generated by one electron gets cancelled by the other electron in the pair. The free electrons that have no pair associated with them are responsible for magnetic properties of the elements.Free electrons that have no pair associated with them are responsible for magnetic properties of the elements.
How Magnets Pull
So how do tiny electrons pull big pieces of ferrous materials? In magnets, all the free electrons are aligned in the same direction. This means that north poles of all tiny magnets are in one direction, which becomes the magnet’s north pole, as shown in Figure 2.
Figure 2: Free Electrons Before and After Alignment
When any magnetizable material, say a piece of iron, comes within the magnetic field of a magnet, north pole of the magnet attracts the south poles of the free electrons. That’s how the iron piece gets pulled and stuck to the magnet. Simple really, you would say. Next time you have a magnet in your hands, I am sure you will not wonder how it attracts iron, but rather try to find its two poles!!
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