Overview of Magnets
A magnet is basically just a substance that has a magnetic field. Now, the magnetic field isn’t visible. You can’t see it in the air, but you can see the results of it. Take a refrigerator magnet for example. It attracts the refrigerator door to itself.
You can see the result of the magnetic field, because the magnet is sticking to the refrigerator door. You can also see the results of a magnetic field when two magnets interact with each other.
You may have noticed that if you put two magnets near each other, they are attracted to each other and come closer to each other. Then, if you turn one of the magnets around, they repel each other and push away from each other.
When talking about magnetic materials, we refer to the materials as ferromagnetic, because they have the ability have a magnetic field. Within the category of ferromagnetic materials, we have soft materials and hard materials.
A soft ferromagnetic material is some type of material that responds to a magnetic field and will have that magnetic field for a little bit but quickly loses it. Now, every substance on Earth in some way responds to a magnetic field, but soft ferromagnetic materials are the ones that respond a little bit more to that magnetic field.
Now, a hard ferromagnetic material is some kind of material that responds very well to a magnetic field. It takes on that magnetic field and contains it for a long time. Permanent magnets are made out of hard ferromagnetic materials, because they’re given a magnetic field and they keep it.
It’s really hard to take away that magnetic field from that substance, such as a refrigerator magnet. It’s been magnetized and it’s hard to unmagnetize it. There is also something involving magnets called an electromagnet.
An electromagnet is basically a coil wrapped around some sort of soft ferromagnetic material. When electricity is turned on, the coil becomes magnetized. When you turn the electricity off, it no longer has a magnetic field.
The soft ferromagnetic material that it’s wrapped around is generally steel. Again, just when you turn the electricity on, the coil and the steel inside of it exert a magnetic field. Then, when you turn the electricity off, they no longer have a magnetic field. Those are some of the important things to remember about magnets.