Magnetism

Magnetism is a HUGE topic to cover. In it's essence, magnetism is "... a class of physical phenomena that are mediated by magnetic fields. (Wikipedia)" This doesn't explain much, but it is a good place to start. Magnetism is a physical phenomena. Think of it like gravity. There is a direction the force is acting and its magnitude is quantifiable. Things react to the magnetic force just like things react to the gravitational force. We know from experience that gravity is rather consistent in everyday life. Now I want you to imagine walking in the park. You're just strolling along on a tranquil Sunday afternoon, and all of a sudden you are thrown to the ground and it feels like your body weighs 5000 lbs. You've accidentally walked into an area where gravity is magnified. Does this happen in real life? Of course not! But this is the same exact effect that the extreme magnetism of rare earth elements has on the magnetic field around it. Think of an element that would have the same influence on the gravitational field that REEs have on the magnetic field. It certainly does not exist (that I know of), but if it did, imagine the implications it would have on technology.

Basic Types of Magnetism

Ferromagnetism: This is the type of magnetism that people think of when asked to describe magnetism (like the one on your fridge). Materials that exhibit ferromagnetism include iron, cobalt, nickel, and the REEs. What is special about ferromagnetic materials? They exhibit magnetism "outside" of an induced magnetic field. This is a really big deal!

Ferrimagnetism: Very similar to ferromagnetism, except the internal arrangement of spinning valence electrons are such that a ferrimagnetic material the same size and shape as a ferromagnetic material will always be weaker.

Antiferromagnetism: This type of magnetism is literally "no magnetism."

Paramagnetism: This type of magnetism, along with diamagnetism, is only exhibited when a paramagnetic material is exposed to an induced magnetic field, such as that created by flowing charges (electric current). Common paramagnetic materials include aluminum, gold, and copper.

NOTE: A material can exhibit all 4 of these types of magnetism. Wait, how is that possible? The type of magnetism a material exhibits depends on the temperature of the material. Just like how the arrangement of H20 molecules, and thus it's state of matter, depends on temperature. Same concept.

Why Should We Even Care About Magnetism?

Magnetism is a very complex subject. So why should we care? Magnetism and electricity are intertwined at the most basic level, and so one must always accompany the other. Now, I know you care about electricity. Okay, I KNOW you care about your Instagram post, which runs on your phone that is only alive because there is a power grid to feed it. The power grid is governed by the laws of not electricity, not magnetism, but electromagnetism. That is why you care about magnetism.